Dear Tom and Ray:
I have a 2002 Honda Civic. My air conditioner starts off blowing cool air, but after several miles of driving, it blows only hot air. The Honda dealer told me the compressor is shot and must be replaced (total cost just under $1,500). I took it to an independent mechanic, who said the compressor is not shot and recommended instead that I go to a dealer and get a set of four new sensors (that are next to the fuses) to replace the current ones (total cost: a few bucks each). He said the sensors appeared to "get hot," and that might be causing the compressor to shut off. Any ideas? Thanks. — Steve
Tom: Well, assuming they checked your refrigerant level and it's not low, my idea is the same as the Honda dealer's, Steve: I suspect your compressor is shot. This is a classic symptom. And your car certainly is old enough to need a compressor.
Ray: My guess is that the "sensors" your mechanic referred to actually are the air-conditioner and cooling-fan relays. Those always get hot when the compressor is running, so they might be fine.
Tom: But if you want to, you can try his advice. Pick up the four relays (they're probably $15 apiece), and have mechanic No. 2 install them and see if that fixes it.
Ray: If it does, you'll be thrilled. But I suspect it won't, and then your total bill will be $1,560. Good luck, Steve.
(Car Talk is a nationally syndicated column by automotive experts (and brothers) Tom and Ray Magliozzi. Write to them at the Car Talk website.)