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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 >
AGCO vehicles and mobile A/C repair
September 13, 2021
Sherwood Wheeler of AGCO will present product updates on AGCO built products Including TSB information, product improvements, refrigerant capacity updates for new models and approved revisions during MACS heavy-duty and off-road program.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 >
The Humble Mechanic wants to see you at MACS
September 2, 2021
Charles Sanville, better known as the Humble Mechanic is MACS Keynote Speaker. Come see Charles on Thursday, September 30 at 11:30am at The Rosen Centre Hotel in Orlando, FL.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 >
2021 MACS Trade Show Exhibitors
August 19, 2021
Come visit the exhibitors at MACS 2021 Training Event and Trade Show.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 >
Come to Orlando for MACS 2021 Training Event
July 21, 2021
Pete Meier of Motor Age explains the value of attending MACS 2021 Training Event and Trade Show!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 >
Time to make your Rosen Centre Hotel reservation for MACS Training Event
June 10, 2021
Time is running out to make your 2021 MACS Training Event and Trade Show hotel reservation at the Rosen CentreRead 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 >
FutureTech Auto Presents Virtual Automotive Software & Electronics Fundamentals Boot Camp with Sponsorship by Mobile Air Climate Systems Association (MACS)
May 19, 2021
After launching the virtual edition of the ASE award-winning Automotive Software & Electronics Fundamentals Boot Camp in May, FutureTech has partnered with MACS to present an accelerated course track in Fall 2021.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 >
Registration is now open for MACS 2021 Training Event and Trade Show
May 3, 2021
Come join MACS in Orlando, FL to attend the 2021 Training Event and Trade Show, registration is openRead 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 >
The Humble Mechanic, Charles Sanville to deliver MACS Keynote address
April 12, 2021
Charles Sanville, known as The Humble Mechanic, will deliver the Keynote address for MACS 2021 Training Event and Trade Show in Orlando, FL.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 >
MACS Live Chat (Richard Hawkins and Steve Schaeber discuss Service Port Location)
July 7, 2020
This live chat features Richard Hawkins, A/C Tech line specialist and MACS technical contributor. Like many of you are during this Coronavirus Pandemic, all of us here on the MACS...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 >
Meet MACS Member Joey Rosato of Texas Truck A/C
June 17, 2020
Joey Rosato is second-generation and Director of Marketing for family-run Texas Truck A/C in Dallas, TX. Joey tells us, “It all started in 1996, when Nick Rosato (Joey’s Dad) set...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 >
MACS talks to GDP’s Julian Hentze about mobile A/C parts, repair and more!
May 7, 2020
A conversation with MACS member Julian Hentze of GDPRead 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 >