For years, RockAuto has been featuring customers’ cars on our Collector Series Magnets, and including one inside the shipping box with most orders. They are real cars that are still on the road today, thanks to their owners’ loving care and parts purchased on RockAuto.com.

Expect to see magnets from this latest batch in your orders soon!

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In the 1970s, I was a college student in Boston with little money, but I needed a car. I found a cheap 1967 Camaro that a mechanic was selling. It ran rough, and he said it just needed a tune up. I bought it and started looking into it and decided to pull the top of the engine off in order to replace the lifters. I could see one of the lifters was newer than the others - apparently the seller had already suspected the rough running engine was due to the valvetrain...hmmm. I put the engine back together...it still ran badly.

I decided to take it apart again to inspect the camshaft. One lobe was completely rounded. After replacing the camshaft and putting the engine together yet again, it still ran badly. After scratching my head and pulling my hair (I had hair back then) I discovered that at some point, I had swapped two spark plug wires on the distributor cap. I fixed that and the Camaro fired right up and purred like a kitten! I put the convertible top down and drove off with a huge smile. The camshaft certainly needed to be changed but when did the spark plug wiring get screwed up? How much time and frustration was spent on such a simple error? I made a note to myself as I drove around to check the simple things first and be prepared to take what a seller says with a grain of salt.

Phil in Oregon

R-134a air conditioner (A/C) refrigerant had to replace R-12 refrigerant no later than the 1994 model year because chlorine in R-12 (a chlorofluorocarbon) damaged the ozone layer. Unfortunately, R-134a (a hydrofluorocarbon) is a greenhouse gas that traps atmospheric heat 1,430 times worse than carbon dioxide (CO2) does. This means R-134a has a "Global Warming Potential (GWP)" of 1430.

US regulations forced new cars to stop using R-134a A/C refrigerant no later than the 2021 model year. Many car manufacturers actually began gradually switching from R-134a to a refrigerant with a lower GWP over a decade ago. Governments have not mandated that manufacture of R-134a be stopped. Therefore, it should be possible to continue to repair and maintain older A/C systems that use R-134a.

The most commonly used low GWP refrigerant is R-1234yf (a hydrofluoroolefin). R-1234yf is a much less potent greenhouse gas with a GWP of 4. A decal in late-model vehicles' engine compartments (example decals shown below) indicates which refrigerant the A/C system uses. Some vehicle models with the same model year came from the factory with A/C systems using different refrigerants. R-134a and R-1234yf systems often use many of the same major parts but usually require different A/C refrigerant oils. The refrigerants are not interchangeable. A/C systems typically use different hose fittings to prevent the two refrigerants from being inadvertently mixed. All this makes it even more important when servicing an A/C system to check the under hood decal and make use of the part descriptions and part photos under "Heat & Air Conditioning" in the RockAuto.com catalog.

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Under Hood Decals

R-1234yf will probably not be the last refrigerant name we will have to learn. Its GWP of 4 still means it is four times as bad a greenhouse gas as CO2 is. R-1234yf is also expensive, typically costing about five times as much as R-134a.

The biggest problem may be that R-1234yf is not the best choice for the heat pumps electric cars need to heat/cool the interior and maintain the temperature of the batteries and electric drivetrain. (Heating up an electric car's interior by using the propulsion batteries to heat up resistors/filaments is inefficient and would drastically reduce the vehicle's driving range. Try warming up a car's cold interior using a hair dryer. The dryer will use a lot of watts of energy, but the interior will stay cool.)

The most successful system (so far) for electric cars is a heat pump that works to make best use of any heat transfer potential available from the batteries, drivetrain and interior heat and A/C system. For example, a heat pump system might have two A/C condensers, one exposed to exterior air to release waste heat on hot days and one inside the car to warm up the interior on cold days.

R-1234yf loses its ability to transfer heat by evaporating and condensing when temperatures fall lower than about 23 degrees F (-5 C) so heat pumps capable of really heating up a car's interior in colder climates (like much of the US and most of Canada) will need a different refrigerant.

The preferred refrigerant may eventually become a CO2-based brew called R-744. R-744 is CO2 so it has a GWP of 1. R-744 costs much less than R-1234yf and can continue to transfer heat in a heat pump system even in cold climates. German car manufacturers have already started using R-744 in some of their models sold in Europe. R-744 has its downsides. For example, R-744 requires much higher pressures which means system components are more expensive to make and harder to seal. I personally plan to keep maintaining and driving my old cars while the future of refrigerant (and a few other things) sorts itself out.

Tom Taylor,
RockAuto.com

To read more of Tom's articles, click this link and choose from story titles on the Newsletter Archives page.