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 >
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 >
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 >
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 >
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 >
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 >
