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The most important Tool
May 10, 2022
There is one essential tool we do not discuss enough that is the most important tool of all. TRAINING! No tool in your toolbox is going to work until you know the why, what, and when of how to use it.Read Article >
A new refrigerant for Trucks?
May 4, 2022
EPA has listed HFO-1234yf under the Significant New Alternatives Policy Program for Motor Vehicle Air Conditioning in Non-road Vehicles and Servicing Fittings for Small Refrigerant CansRead Article >
Compressors 101
May 2, 2022
You are invited to attend a compressors 101 class I will be conducting next week at the MACS training facility in Lansdale, PA. The title of the class is Behavioral Characteristics of Various Compressor Types. It is happening live on Wednesday May 11 from 5:30 to 9:00pmRead Article >
Tools and Diagnostic Equipment for Mobile A/C Service
April 29, 2022
Remember it is up to the individual service company or technician to ensure they are following the requirements established in the location where they are working.Read Article >
Vacuum pump maintenance
April 26, 2022
As mentioned in last week's blog post, vacuum pumps require regular maintenance and frequent oil changes and We wanted to provide information on the intervals, so we polled several vacuum suppliers.Read Article >
Your A/C season supply list
April 20, 2022
Unfortunately, something that is often absent from these A/C shopping lists is vacuum pump oil, and multiple containers of it should be included.Read Article >
The desiccant myth
April 12, 2022
There is a myth that exists involving A/C service work and driers that seems to come up from time to time. I have encountered it when handling tech calls and have seen it come up in A/C forums. Read more to find out what it is.Read Article >
The value of a MACS membership
April 8, 2022
Someone asked me recently, “What’s the value of a MACS membership?” The question was an honest one. Why should anyone pay their hard-earned dollars to be a Mobile Air Climate Systems Association member?Read Article >
AirSept Announces the Passing of Founder and Automotive Entrepreneur Myron Stein
April 7, 2022
AirSept, a recognized leader in the automotive aftermarket for developing cost-effective, award-winning solutions for automotive repair, regretfully announces the passing of the company’s co-founder, Myron Stein.Read Article >
MACS 2023 Annual Training Event and Trade Show
April 7, 2022
MACS 2023 Annual Training Event is back on schedule for 2023! We will meet at the Gaylord Opryland Resort in Nashville, TN. February 2-4, 2023.Read Article >
No drier replacement, no compressor warranty!
April 6, 2022
Compressor manufacturers and parts distributors are adamant about driers being replaced when one of their compressors are installed. No drier replacement, no compressor warranty!Read Article >
What is a receiver drier?
March 29, 2022
With A/C season just around the corner, this seems like a good time to provide some updated information on these units. NOTE: Receiver driers are sometimes called filter driers and accumulators are sometimes called accumulator driers.Read Article >
Replacement refrigerant confusion
March 22, 2022
There was a group of several refrigerants which were blends with a high percentage of R-134a and a smaller percentage of R-142 that seemed to be the most popular.Read Article >
Section 609 certification reminders
March 21, 2022
Currently, all technicians must show their certification card to purchase R-134a refrigerant in quantities of 2-pounds or more.Read Article >
MACS Compressor Class
March 17, 2022
Have you ever had questions about why certain types of mobile A/C compressors perform the way they do? Did you wonder who you could ask? Well MACS trainer, Richard Hawkins will be teaching his class Behavioral Characteristics of Various Compressor Types live at the MACS training facility on Wednesday, May 11 from 5:30-9pm.Read Article >
Talking refrigerant safety
March 15, 2022
Let's say I brought my car in to your shop with an A/C problem and described what was going on with it. You might ask me if myself or someone else had worked on it. Right?Read Article >
What does a MACS Section 609 card look like?
March 10, 2022
MACS occasionally receives reports from the field of a technician being refused purchase of refrigerant for not having a proper Section 609 card. Usually this is due to the technician not producing the right card or the counterperson not understanding what a MACS Section 609 card looks like. What does a MACS Section 609 card look like?Read Article >
Refrigerant supply, pricing and safety
March 8, 2022
What I'm hearing about refrigerant supply and pricing this year reminds me of a similar period in the mid-2000s. It was springtime, just before the start of A/C season. Supplies of R-134a were tight and the price had come close to tripling from the prior year.Read Article >
Heat pump basics
March 2, 2022
An internal combustion engine (ICE) is relatively inefficient, using only about a third of the fuel's heat energy (BTUs). The rest of the heat energy is “wasted” in friction, cooling and exhaust heat losses. Yet, the ICE’s wastefulness benefits the vehicle's interior heating.Read Article >
Refrigerant reminders
March 1, 2022
It could be a challenging year keeping adequate supplies of R-134a on hand and it will be more expensive.Read Article >
Checking for refrigerant contamination
February 24, 2022
A large percentage of MACS members have refrigerant identifiers and use of them on vehicles that come into their shop for A/C service prior to beginning any service work is standard procedure. However, there are a lot of non-MACS member shops who do not have identifiers and unfortunately are not aware of the potential issues which can be caused by refrigerant contamination.Read Article >
Correcting user error
February 15, 2022
As mentioned in last week's article, the first thing I did with the machine was check the pressure of the refrigerant in the tank. It was extremely high (well over 400 PSI) indicating there was a refrigerant contamination problem.Read Article >
The benefits of MAP-controlled thermostats
February 9, 2022
A customer driving a 2014 BMW 328i arrived at the college's 2nd-year electrical lab reporting his illuminated check engine light. The customer had no complaints other than the light. The vehicle had just over 82K miles showing on the odometer. A student (Phil) assigned to the BMW performed a review with a scan tool, and a single code (P0597 – Thermostat Heater Control Circuit Open) was present.Read Article >
Sometimes it is user error
February 8, 2022
I encountered a situation in the early days of recovery/recycling machines when they had just been introduced. I had set up a machine about four months earlier when the customer purchased it. I went to great lengths to cover proper operation of the unit and the shop owner even attended a certification clinic I conducted.Read Article >
Air contamination in an A/C system can ruin your day
February 2, 2022
I had a memorable encounter with air contamination in the mid 1990s. I was conducting a lot of retrofit clinics at the time and had recently acquired a demo refrigerant identifier which I took to those clinics. At one clinic, there was a technician who was extremely interested in the refrigerant identifier.Read Article >
Read all about it!
February 1, 2022
Read all about it! MACS February 2022 digital issue of ACTION magazine is ready to view.Read Article >
MACS changes leadership
January 31, 2022
MACS is changing leadership. Elvis L. Hoffpauir, is stepping down at the end of January 2022 from his duties as MACS president and chief operating officer to enjoy retirement. Following a 42-year distinguished career at the Mobile Air Climate Systems Association (MACS), Elvis will transition to past president and association advisor.Read Article >
Heater Insight
January 25, 2022
Recently, a customer brought in a 2006 Honda Insight with a heater that was blowing cold but had no other vehicle concerns. A local garage had informed the customer the head gasket had failed; however, the owner felt a second opinion was necessary.Read Article >
Air contamination in mobile A/C systems
January 18, 2022
We covered a base line test conducted with 0% air contamination and provided pressure and temperature information. This week we will provide pressure and temperature information experienced with 7.7% air contamination and 18.9% air contamination.Read Article >
The effects of air contamination in an A/C system
January 11, 2022
If you perform an Internet search for effects of air contaminated refrigerant on automotive A/C system pressures, you’ll find many results. This information leaves no doubt that air contamination of refrigerant in an automotive A/C system can affect system pressures and temperaturesRead Article >
Variable output scroll compressors
January 5, 2022
This compressor has been around for quite some time and the vehicles it is used on are getting some age on them. However, they still show up in shops with regularity and there still seem to be a lot of technicians that are not aware of the problem, diagnostic procedure and cure.Read Article >
2022 is a great year for MACS training
January 4, 2022
Attend the best mobile air conditioning training classes available!Read Article >
When you don’t know about clutch wires
December 27, 2021
The conversation involved a clutchless compressor unit. A CSR who had sold one to a shop contacted me and said his customer (who was both the shop owner and technician working on the car) had just called him. There was a concern that the compressor didn't have a clutch wire.Read Article >
An overview of electronic variable displacement compressors
December 21, 2021
we have focused on electronically controlled variable displacement compressor operation and behavior. It is important to have a good understanding of how these compressors operate and behave. This is because the percentage of vehicles coming into shops using these units is growing and will continue to grow.Read Article >
Helping your customer understand their A/C repair
December 16, 2021
To help service shop owners, MACS has created a 30-page consumer guide for your customers that explains how their car’s engine cooling system and air conditioning system works. “Getting to know your car’s air conditioning and engine cooling system,” details how these vital climate systems work and why they may require an extensive repair.Read Article >
Testing an electronically controlled variable displacement compressor
December 14, 2021
The A/C system was run with the vehicle's computer controlling the compressor. When the heat loads were changed, there were noticeable changes in the duty cycle signal being supplied to the compressor.Read Article >
The pulse width modulated duty cycle signal
December 7, 2021
Several years ago, when vehicles using these compressors were just starting to show up at shops for service with some regularity, we were searching to find some detailed information about their behavior to use in clinics. There was not a lot of it available, so we borrowed several vehicles and did some videos. The following are some clinic slides produced from one of those videos.Read Article >
Bipartisan infrastructure package authorized $7.5 Billion for EV charging.
December 2, 2021
This week, the U.S. Department of Transportation (DOT) took the first steps in establishing programs for a national network of electric vehicle charging stations, as mandated in the bipartisan infrastructure bill passed earlier this year.Read Article >
Virtual automotive software & electronics fundamentals boot camp
December 1, 2021
The boot camp will teach learners how to quickly create circuits and code software to build their own diagnostic tools or training aids. They will also learn how to control advanced vehicle systems for the purpose of diagnosing real (or simulated) problems. Automotive service professionals will develop skills to create simulators, demonstrators, and will also learn how simple electronic and software circuits can be used with the Scan Tool to develop circuits that can make complex diagnostics easier.Read Article >
Diagnosing electronically controlled compressors
November 30, 2021
When preparing to conduct diagnostics on a system using an electronically controlled variable displacement compressor, the diagnostic process needs to focus on four areas.Read Article >
Exploring electronically controlled variable displacement compressors
November 23, 2021
Electronically controlled variable displacement compressors (ECVDs) have been in use now for over 15 years. However, there are a lot of technicians in the field who have very little knowledge about them and their operation.Read Article >
EPA releases Automotive Trends Report
November 19, 2021
Vehicle enthusiasts may want to check out the U.S. EPA's newly released Automotive Trends Report.Read Article >
Electronically controlled variable displacement compressors
November 16, 2021
what if" this system used an electronically controlled variable displacement compressor instead of the pressure controlled variable displacement compressor? What would the results be?Read Article >
Disassembly and inspection of a seized compressor
November 15, 2021
MACS Tim Iezzi takes apart a problem compressor in this step-by-step video.Read Article >
You can get Tesla repair information
November 10, 2021
Find out how to use Tesla software for aftermarket repairRead Article >
Troubleshooting the “what ifs” in a mobile A/C repair
November 9, 2021
High side: Likely somewhere around 130 psi (at an idle) & 140 psi at 1500 rpm. Why? With only a 35% charge in the system, the compressor isn't going to be producing a lot of pressure.Read Article >
Meet MACS member, Tom Lech
November 8, 2021
Stationed in San Francisco, California, Thomas Lech has maintained a bustling business for almost three decades. Lech Auto Air Conditioning has been busy for 365 days a year from opening at 7 a.m. to closing at 7 p.m. for the last 27 years, with summertime only increasing the demand for the shop’s services.Read Article >
What do you know about the fixed displacement piston compressor?
November 2, 2021
What do you know about the fixed displacement piston compressor?Read Article >
Bring the heat!
November 1, 2021
At this time of year, I often end up with an earworm in my head from a Canadian rock band … Summer’s going fast, the nights are growing colder. Then it’s the line everyone knows from something more mainstream … Winter is coming. It’s early September, and the leaves on some trees are already starting to change. Winter is coming.Read Article >
Tesla aftermarket repair information
October 29, 2021
NASTF has released new information on industry changing news! After 4 years of working together with Tesla, NASTF is pleased to announce that Tesla scan tool and service information is now available to the aftermarket. For the American and Canadian markets (Canadian version is in the final testing stages) things are changing rapidly that's why the National Automotive Service Task Force (NASTF) has brought their best experts to explain how to find, set-up, and implement this new information so you can add this new service opportunity to your shop.Read Article >
J1587/J1708 and J1939 data line diagnostics
October 27, 2021
Modern heavy-duty equipment is basically comprised of computers with operating units attached. In short, it is a multiplexing system that replaces traditional power distribution devices with ECUs that communicate electronically over the vehicle datalink.Read Article >
Compressor diagnosis
October 26, 2021
It is important to know the correct answer, but it is more important to know why it is the correct answer. Please picture #4 for more information on that.Read Article >
The concept of superheat
October 19, 2021
We illustrated the concept of superheat in last week's article by boiling water and superheating steam in a moonshine still. This week we will apply this concept to refrigerant in an air conditioning system. The still has been replaced with an evaporator.Read Article >
Over 500 automotive scholarships available
October 14, 2021
The University of the Aftermarket Foundation (UAF) is now accepting scholarship applications for the 2022-2023 school year on its Automotive Aftermarket Scholarship Central website. Scholarships from UAF and more than 40 donor organizations are consolidated and easily accessible at AutomotiveScholarships.com.Read Article >
More on the behavioral characteristics of various compressors
October 12, 2021
Last week's article ended with a slide from my class at the MACS Training Event & Trade Show. If you haven't already read that article, you may want to do so. That slide had the following question in it: Finally, with a 30 to 32 PSI low side, why is the suction line temperature 65° FRead Article >
A beautiful day for golf
October 8, 2021
Here’s a Friday Flashback to Wednesday, September 29th, a beautiful day for golf. The MACS 41st annual golf tournament was played at Shingle Creek golf course in Orlando, FL.Read Article >
Airsept, Burgaflex and Sanz Kenway honored for MACS Trade Show best new products
October 7, 2021
Three MACS member companies received honors for their new products introduced at MACS 2021 Trade Show, October 1st at the Rosen Centre Hotel and Convention Center in Orlando, FL.Read Article >
Don’t try this at home
October 6, 2021
Don't try this at home! We do not recommend adding a machete to your mobile A/C tool kit. However, in Belize they do things differently. Sometimes necessity is the mother of invention.Read Article >
Behavioral characteristics of various compressor types pt. 2
October 5, 2021
So now it is time to provide the correct answer along with information on why it is correct and also information on why the others are incorrect.Read Article >
Thank you 2021 MACS Training Event Attendees
October 4, 2021
Thank you to all the attendees who travelled to Orlando, FL for MACS 2021 Training Event and Trade Show.Read Article >
Transit bus cooling system overhaul
September 28, 2021
Upon inspecting the 300,000-mile bus, we found several concerns likely contributing to the engine’s overheating situationRead Article >
Understanding and troubleshooting data lines on heavy-duty trucks
September 23, 2021
Understanding and Troubleshooting data lines on heavy-duty trucks will be presented byLarry Turay of LETCO Enterprises. In Larry’s Saturday morning class, attendees will learn how components and subsystem inputs and outputs can influence HVAC operations.Read Article >
AEM Update: Snap application for off-highway R-1234yf
September 22, 2021
MACS will have a variety of heavy-duty and off-road presenters beginning at 8 am on Thursday, September 30. One will be AEM Update: Snap application for Off-highway R-1234yfRead Article >
Behavioral characteristics of various compressor types
September 21, 2021
When faced with a challenging A/C system problem, knowing what type of compressor you are dealing with can help streamline the diagnosis process.Read Article >
The cool kids ride air conditioned school buses
September 17, 2021
More and more school districts are requiring their school transport buses to be air conditioned. On blazing hot days, high in humidity, it is a matter of comfort for riders. In the era of COVID-19, filtration of the air is an important matter of safety.Read Article >
Cooling fan circuit analytics
September 16, 2021
What is Peter Orlando’s class Cooling Fan Circuit Analytics about? It all began decades ago as a mechanical fan attached to the water pump with and without a fan clutch. And now it has evolved into an efficient complex electrical motor control of cooling the modern internal combustion engine.Read Article >
Understanding and diagnosing air conditioning
September 15, 2021
Most of today’s vehicles come equipped with electronically controlled A/C systems. Auto A/C systems have become more difficult to diagnose using the repair strategies learned from years of servicing R-12 and R-134a systems.Read Article >
A burned clutch is a symptom of another problem
September 14, 2021
Not much thought is given to compressor clutches until they fail, but they are extremely durable. I have personally owned three vehicles that had between 200, 000 and 240,000 miles on them. They all still had the original compressors and clutches, and they were still functioning perfectly.Read Article >
Facts to know about the compressor clutch coil
September 7, 2021
Checking the clutch air gap before installing a compressor is an important step in compressor installation. This is because of the possibility of a clutch air gap getting knocked out of adjustment due to rough handling or it being gapped incorrectly at the factory. These issues of course can cause problems with clutch operation. If detected and corrected before compressor installation, a lot of time can be saved.Read Article >
Back to school bus A/C
September 1, 2021
Since it’s September (and another school year is upon us), we’re going to look at what’s so different about school bus A/C as compared to the more common automotive-type systems.Read Article >
Mind the compressor clutch gap
August 31, 2021
One of the first things I was taught in my A/C training was to always check the clutch air gap prior to installing a compressor.Read Article >
Who are MACS future leaders?
August 27, 2021
Nominations are now open for the 2022 MACS board of directors’ election. Are you ready to get involved and help shape MACS for the future?Read Article >
MACS Tesla project
August 26, 2021
MACS is working on a project, to collect A/C charge information for Tesla vehicles, and we need your help!Read Article >
Two clues to a condenser’s identity
August 24, 2021
There are two steps to determining what type of condenser is in a vehicle.Read Article >
What type of condenser is in that vehicle?
August 17, 2021
What type of condenser is in that vehicle? It's a frequent question in the mobile A/C industry.Read Article >
Mysterious servicing issue in R-1234yf systems
August 11, 2021
Recently a 2017 R-1234yf Honda system, with 72,099 miles, encountering a loss of cooling (slow leak) over time would not pass the equipment charge procedure and the production amount could not be charged.Read Article >
Field study: Incorrectly installed condensers
August 10, 2021
I have handled numerous tech calls involving older GM trucks with incorrectly installed condensers. In preparation for this series of MACS blogs, I discovered a salvage truck with one of these condenser repairs. This gave me the opportunity to duplicate the incorrect installation and look for pitfalls and solutions.Read Article >
Finding right side up
August 3, 2021
Most condensers have different fittings on the inlet and outlet. The locations of the inlet and outlet on most condensers will not allow lines to be connected incorrectly, even if the fittings do happen to be the same size. Lastly, the designs of the mounts on most condensers prevent a unit from being installed upside down. However, none of these characteristics apply to the condenser the technician had installed.Read Article >
MACS Modern HVAC textbooks in stock for back to school
July 28, 2021
MACS Modern HVAC textbooks are in stock for back-to-school purchase.Read Article >
Did you install the condenser upside down and backwards?
July 27, 2021
The vehicle was a 1998 Chevrolet C 1500 truck with a 5.7 engine. The issue was excessive high side pressure. Almost as soon as the compressor clutch engaged, the high side pressure was over 400 PSI, and the high-pressure cut-off was turning the compressor on and off.Read Article >
Top three tips on orifice tube behavior
July 20, 2021
In the last four MACS blog articles we covered a lot of detailed information about orifice tube system behavior. We examined a system with a full refrigerant charge verses a 25% undercharge. Now it is time to condense it all down into three important takeaways.Read Article >
Truck A/C is a hot commodity
July 14, 2021
Look out on your local highway, and what do you see? Truckers getting the job done. They want their cabs to be cool in summer and warm in winter. They want the climate system to work right. There is no time for downtime. That is where we come in.Read Article >
Low refrigerant charge and the search for real data part 4
July 13, 2021
When we examined the pressure readings and vent temperature readings last week, there was nothing showing up that indicated any charge issues (even operating with the 25% undercharge).Read Article >
MACS Service Reports: a valuable member benefit
July 9, 2021
The MACS Service Report is a valuable MACS member benefit. Published nine times annually for dues-paying MACS members, MACS Service Report is an in-depth technical newsletter.Read Article >
We can’t wait to see you in person!
July 8, 2021
We are just a little over two months away from the rescheduled 2021 MACS Training Event and Trade Show! We can’t wait to see you in person September 30 through October 2 at the Rosen Centre Hotel in Orlando, FL. The golf tournament will be played on September 29 at the Rosen Shingle Creek Golf Course.Read Article >
Low refrigerant charge and the search for real data part 3
July 6, 2021
To place as much heat load on the system as possible, we turned the heat in the shop up on high and got it as hot as possible before beginning the test. When the temperature peaked at 89°, we began the test. We tried to keep it constant, but all the heat being generated by the engine in the test vehicle caused it to inch upward by 2.5° before the second test was concluded.Read Article >
A/C for E-trucks
July 1, 2021
Are you ready for E-trucks? Find out in the July/August 2021 issue of MACS ACTION magazine.Read Article >
Low refrigerant charge and the search for real data: part 2
June 29, 2021
The purpose of the test was to run an orifice tube system with a full refrigerant charge and then with a 25% undercharge and compare pressure readings and temperatures at strategic points in the system.Read Article >
What’s the word on R-134a price & supply?
June 24, 2021
The email questions are already coming in, and they go kind of how you’d expect: What’s going on with the price of R-134a? Is there going to be a shortage of R-134a supply?Read Article >
Low refrigerant charge and the search for real data
June 22, 2021
I had read about how low refrigerant charges could increase compressor operating temperatures and decrease the amount of oil flowing to compressors, but I had never been able to find results from any tests. After discussing this with MACS, we decided to do some testing to get some real data.Read Article >
Refrigerant capacity and mobile A/C service: part 2
June 15, 2021
One of the most frequently asked questions on tech help-line calls concerns refrigerant capacity: How much refrigerant is in that mobile A/C system, and have you checked to be sure the refrigerant is pure?Read Article >
Mobile A/C training when you want it!
June 14, 2021
If you’ve been too busy or the COVID-19 situation has made it difficult for you to attend mobile A/C training MACS has the solution.Read Article >
Refrigerant capacity and mobile A/C service
June 8, 2021
One of the most frequently asked questions on tech help-line calls is: How much refrigerant is in that mobile A/C system, and have you checked to be sure the refrigerant is pure?Read Article >
Robinair sponsors free Section 609 test prep webinar and test for 500 technicians this summer
June 7, 2021
Robinair sponsors free Section 609 test prep webinar and test for 500 technicians this summerRead Article >
Electrification and climate control technologies: Are we prepared?
June 3, 2021
A recent survey from CarGurus suggests consumer interest in purchasing an electric vehicle (EV) has doubled in the past three years.Read Article >
Focus on the condenser!
May 31, 2021
In last week's article, we focused on applying temperature testing to an evaporator in an orifice tube system. In it we illustrated how and why a low liquid level in the evaporator can cause a large temperature differential between the inlet and outlet. We also indicated how and why raising the liquid level will cause the temperature differential to decrease. Now it is time to focus on the condenser.Read Article >
Show me your MACS 609 card
May 26, 2021
When you purchase refrigerant in quantities of two pounds or more you must show your Section 609 card.If you are Section 609 certified through MACS between 1991 and May 2021...Read Article >
Temperature testing detective work: The search for a diagnosis
May 25, 2021
Last week we closed our blog post with a discussion about an orifice tube system which had an evaporator outlet temperature that was about 20° warmer than the inlet. We mentioned that this could be an indication of a restricted orifice tube or a refrigerant undercharge. In applying this to diagnostics, it is important not only to understand what this represents, but also why.Read Article >
What is your temperature testing data telling you?
May 18, 2021
If air conditioning systems were transparent where we could see inside them, then diagnostics would be faster and easier. We could look at the systems and see things right away that affect system operation, like restrictions and liquid levels in evaporators and condensers.Read Article >
Do you have the essential tools for success?
May 17, 2021
Using the correct tools to service and repair vehicles is so important that the Society of Automotive Engineers (SAE) creates standards for some service tools to meet. Requirements for their use by service professionals is included, as well. Some examples include refrigerant recovery and recycling machines, refrigerant identifiers and leak detectors.Read Article >
AIM: EPA’s HFC Authority Is On!
May 14, 2021
On December 27, 2020, President Trump signed into law the Consolidated Appropriations Act, which at $2.3 trillion is one of the largest spending bills in US history. It combines $600 billion in COVID relief with $1.4 trillion in twelve different appropriations bills. One of them is the AIM Act.Read Article >
Temperature Matters
May 11, 2021
In addition to having good contact with connectors and getting accurate readings, there are some other important things to remember when doing temperature testing.Read Article >
Pass the temperature probe
May 4, 2021
The first step is to run the A/C system for a few minutes to let it stabilize. Then both probes should be connected side by side at both points that will be temperature tested in the system. For example, if you were testing the temperature drop across the condenser, this would need to be done on both the discharge line and the liquid line.Read Article >
Are you using the right tools for mobile A/C repair?
April 30, 2021
Your shop’s R-134a recovery/recycling/recharge (R/R/R) machine is in well-maintained condition. You have an R-1234yf gauge manifold set and an R-1234yf machine is on order; should arrive shortly.Read Article >
Contact counts in temperature testing
April 27, 2021
Proper contact is vital when connecting to A/C lines using the contact type temperature thermometers. To determine if I am getting good contact, I always like to place both connectors side by side on the same line and observe the temperature readings.Read Article >
MACS Mobile A/C Update Webinar Now Available On Demand
April 22, 2021
Every year the Mobile Air Climate Systems Association creates a special mobile A/C update clinic to help working technicians keep up with the rapidly changing mobile A/C service and repair...Read Article >
Tips for taking your mobile A/C system’s temperature
April 20, 2021
The contact type units do indeed have a high degree of accuracy, but precautions must be taken when using them (especially connecting to lines) to ensure the accuracy. Otherwise, it is possible to get readings that are easily 5° to 10° off and that can lead to an incorrect diagnosis.Read Article >
The pressure is on
April 19, 2021
By appearance, radiator caps seem to be a simple device. Yet, many technicians do not understand the cap’s real functionRead Article >
Temperature testing accuracy
April 13, 2021
Temperature readings can be easily used to determine if an orifice tube system might be undercharged, and they can also be used to charge an orifice tube system. But if the readings are not accurate, all they are going to do is cause you problems.Read Article >
Then things got complicated!
April 9, 2021
It was a 2013 Camaro. The complaint was poor cooling and the temp really would not change when you switched it from heat to cool. In diagnosing the job, the technician found the blend door was stuck to where it was blending heat. Until it was pulled out, the tech was not sure if it was a bad actuator or door.Read Article >
Avoiding an oily situation
April 6, 2021
If you own a mobile A/C repair shop this is when you start to gear up for it, by replenishing your parts inventories and an important segment of those inventories is compressor oil.Read Article >
Preseason Training: A Service Manager’s Guide to Preparation
April 1, 2021
Proper training can limit the time period that any given mechanic spends in the novice stages of their career, and it may help them advance to expert performance levels in an expedited time period.Read Article >
How to deal with a compressor oil viscosity change
March 30, 2021
dealing with a catastrophic compressor failure where system flushing and component replacement removes all the oil from the system, then it is a matter of just installing the correct quantity of the oil that is specified for the replacement compressor.Read Article >
Texas Truck A/C thrives for 25 years
March 29, 2021
As Texas Truck A/C owners, employees, and customers celebrate the company’s 25th anniversary of being in operation, this business demonstrates what it means to not only survive for 25 years but to thrive.Read Article >
ParkSmart Bunk A/C System Freightliner P3 Cascadia
March 24, 2021
The ParkSmart auxiliary HVAC system has been offered to replace the standard auxiliary HVAC unit.Read Article >
Why does the replacement compressor use different oil (than the original unit)
March 23, 2021
That is viscosity and specifically why a replacement compressor might use a different viscosity oil than its OEM counterpart.Read Article >
Does the compressor contain oil?
March 17, 2021
A question that comes up frequently on A/C tech lines is: Does the compressor contain oil and if so, how much?Read Article >
Marks Air celebrates 50 years of mobile air success
March 16, 2021
MACS member Marks Air Inc. celebrates 50 years of being in business.Read Article >
Tank full of air!
March 15, 2021
The problem is usually caused by excessive air in a system, and since too few shops use a refrigerant identifier, they don’t know when these problems come up, nor how often they are solving problems by doing this.Read Article >
Time to plug into EV training
March 10, 2021
Read any automotive publication or website, and you will see numerous stories from all the big automotive manufacturers and quite a few shiny new start-ups about vehicle electrification.Read Article >
How much oil “goes” in the compressor?
March 9, 2021
There is also an additional step which is required in the oil draining process with this unit. That step is that the suction damper needs to be depressed to allow proper ventilation when draining one of these compressors.Read Article >
Helpful tips to register for MACS online training clinics
March 5, 2021
Helpful tips on how to register for a class on the MACS websiteRead Article >
“Balancing” oil balancing
February 23, 2021
What should we do if performing an oil balance and only 1/4 oz of oil drains from the original compressorRead Article >
Caveman to Mr. Cool
February 18, 2021
Over 300,000 years ago, modern man began walking the earth relying heavily on his five senses-- especially sight – to hunt, find joy, and avoid danger. In 1914, Garrett Morgan, who decided it was important to protect man’s eyes during hazardous situations, developed what we know today as ‘safety’ glasses.Read Article >
Fix it correctly the first time
February 15, 2021
A cooling system classroom lesson By Christopher J. Holley, MACS Contributing Editor A 2017 Accord with an overheating 2.4L engine arrived at our college lab. The customer had a limited...Read Article >
A Change in Temperature
February 10, 2021
Using a contact thermometer, they quickly discovered 50° on the suction line at the expansion valve, and down at the compressor it read 96°. Along any length of hose or tube, there should be very little change in temperature.Read Article >
Compressor Oil: When is it enough?
February 9, 2021
But how do we know that a system has the correct amount in it to start with?Read Article >
MACS Board of Directors Elects 2021 Officers
February 8, 2021
The board of directors of the Mobile Air Climate Systems Association (MACS) met virtually Friday, February 5, 2021, and elected officers for the year. Andy Fiffick of Rad Air Complete...Read Article >
Stop by macsmobileairclimate.org for a visit
February 5, 2021
Visit MACS at macsmobileairclimate.orgRead Article >
Doing the repair right
February 4, 2021
By Richard Hawkins, MACS Contributor The focus in the two previous weeks articles on the Chevy Tahoe was on what went wrong and what should have been done to correct...Read Article >
The beginning of a New year, new MACS!
February 1, 2021
The Mobile Air Conditioning Society has rebranded to become the Mobile Air Climate Systems Association (MACS). During a year-long project, the MACS board and staff worked with the Blue Door...Read Article >
Tales from the helpline: When they don’t know, what they don’t know!
January 26, 2021
By Richard Hawkins, MACS Technical Contributor Last week, my topic of discussion for the MACS blog was a tech call about an A/C system which was plagued by a huge...Read Article >
How much compressor oil is too much?
January 19, 2021
By Richard Hawkins, MACS Technical Contributor A lot of interesting calls are encountered when working on an A/C tech help line and a large percentage of them involve lubrication issues...Read Article >
Let me tell you a story…
January 12, 2021
I conducted my first A/C clinic in 1991 which of course was 30 years ago. That was right along the time when things were getting geared up for the transition from R-12 to R-134a and was a very interesting period.Read Article >
OSHA and HazCom citations
December 14, 2020
By Charles Ayers, CCAR By the time you read this, the Occupation Safety and Health Administration (OSHA) will have released its “Top 10 Most Frequently Cited” list for fiscal year...Read Article >
Disinfecting of vehicles during COVID-19
November 10, 2020
By Ward Atkinson, MACS Technical Advisor, & Bill Hill, GM Retired Recent comments from government agencies on the COVID-19 virus issue indicate that even when a vaccine is available, our...Read Article >
Hazmats: Why should I care?
September 21, 2020
Trivia question: what do R-134a, Lithium Ion batteries, air bag modules, and used fuel system components all have in common? Aside from the fact that these are all in-use in today’s vehicles, they are all also classified as Hazardous Materials (i.e. hazmats) by the U.S. Department of Transportation (DOT). The same holds true for these products in Canada, where the governing body (Transport Canada) has similar designations for what they call ‘Dangerous Goods’ (i.e. hazmats).Read Article >
Back to basics
September 9, 2020
There is no doubt that when it starts getting hot outside, your shop gets slammed with customers asking for help with their A/C systems. Same thing happens here at MACS, except we get slammed with A/C tech support calls.Read Article >
Understanding data lines (Part I)
September 8, 2020
By Larry Turay Data lines and multiplexing have been with us in the heavy-duty world since 1990. The increased use of ABS, electronic ICUs, and automated transmissions to name a...Read Article >
Are you a diagnostic detective?
September 3, 2020
By Pam Oakes, SME automotive professional If you consider yourself a diagnostic detective see if you can solve this cooling system mystery before the end of the article! Cooling Corner:...Read Article >
Spend some time with MACS president and coo Elvis Hoffpauir
July 24, 2020
Hello, and Welcome to MACS Worldwide’s YouTube Channel. We’re glad you’re here! Elvis Hoffpauir Pioneer Experience MACS History! Elvis Hoffpauir, MACS president and chief operating officer, was presented with a...Read Article >
Name That Hybrid Water Pump
June 29, 2020
By Dave Hobbs, MACS Technical Correspondent While virtually every HEV (hybrid electric vehicle) has an ICE (internal combustion engine) along with one or more high voltage electric motors, not every...Read Article >
MACS Live Chat (John Duerr & Steve Schaeber discuss A/C Leak Detection Tracer dye & COVID-19 in NYC)
May 28, 2020
Hi everyone, and welcome to another MACS Live Chat, hosted by Steve Schaeber, manager of service training and technical editor for MACS publications like ACtion Magazine and the MSR (MACS...Read Article >
Stop complaining about the technician shortage…
April 8, 2020
…and DO SOMETHING ABOUT IT! By Elvis Hoffpauir C.O.O. MACS Worldwide That was the principal message from Peter Meier, Director of Training at Motor Age. Peter, along with MACS Technical...Read Article >
Helpful tactics to minimize the spread of Covid-19 in your service and repair shop
April 7, 2020
By Bill Snow, Radair Complete Car Care, Cleveland, OH With today’s concern about being exposed to COVID-19 shop owners need to take additional steps to protect their team members and...Read Article >
