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I'm freezing, but my car is burning up!

1. Cold heat, hot gauge

Dear Professor: My car's temperature gauge has been reading hot and my heater isn't working very well. I changed the thermostat but that didn't help. Any suggestions? - Angel R.

Dear Angel: Check your coolant level. Insufficient fluid means poor heat transfer from the engine to the radiator. It also means less hot water is getting to the heater core. Even if the coolant level appears to be okay, you may have an air pocket or two which needs to be bled from the system.

This is an easy task if you're lucky enough to have an engine with a bleeder valve. With the engine on, carefully loosen the bleeder valve until the escaping air bubbles are replaced with a solid stream of coolant. Refill your radiator and overflow tank.

If you don't have a bleeder valve, careful remove your radiator cap and run the engine until it reaches normal operating temperature. If your open radiator neck is the highest point in the cooling system, most air bubbles will find their way out. If it isn't the high point, you may need to jack up the front of the car a little. Otherwise, air will remain trapped in the system. Don't forget to fix the root cause of low coolant or air in the system. You may have a slow leak that needs repaired.

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R-12 or R-134A

2. New A/C Refrigerant?

Dear Professor: The air conditioning compressor in my 1990 Mercury recently failed. My technician tells me this is going to be a major repair. Should I go with the new coolant system or stay with the old? – Leonard

Dear Leonard: Decisions, decisions. The old axiom of “fix it up or do without” is rarely applied today. The choice between repairing an older unit and upgrading to a newer model is a modern dilemma. Whether the topic is housing, cars, or romantic interests, nowadays decisions are based on reliability, affordability and receding hairlines. Deciding on whether to repair or update your car’s air conditioning (a/c) unit isn’t any different.

Although you refer to coolant, we are really discussing a/c refrigerant, not the coolant found inside a radiator. Your quandary is based on the belief that chlorofluorocarbon (CFC) type refrigerants, such as R-12, are harmful to the environment. That view of CFC’s led to a ban on the production of R-12, popularly known as Freon . It’s replacement, R-134a, is supposed to be environmentally friendly and has been used now for a number of years. The real question is whether you should repair an older system in the face of dwindling R-12 supplies.

R-12 systems can be retrofitted to work with R-134a, but may not cool as efficiently using the new refrigerant. Therefore, reliability demands you keep and repair your current system. This is the short-term solution. But, affordability demands you convert the system now and not postpone the inevitable. The price of R-12 will continue to increase as stockpiles diminish daily. The cost of future a/c work on this car will eventually force you to convert the system.

Of course, a mid-life crisis suggests you disregard the above and buy a new car. Loyalty and expense mean nothing to a receding hairline. That’s okay. Corvettes have air conditioning too.

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