Your thermostat may be stuck open

Dear Mike: I have a 1999 Oldsmobile Alero GL, and there’s a problem with the heater. It seems to take forever to warm up the cabin of the car, even on high speed. Now, I know it can’t be the heater motor because it was replaced a year ago. I checked the antifreeze, and it was fine. I also use synthetic oil to help with the cold starts.

Is there something else I can check before going to my mechanic and having him tell me that it is all in my head?

A: Start by making sure the thermostat isn’t stuck open, and that the coolant is coming to proper temperature. If it is, check for proper opening and closing of all the air-blend doors in the plenum, and missing or misplaced seals around the doors.

Things still seem all right? Now check for a partially plugged heater core.

With the engine warmed up and the heat on “hot” and the blower on “high,” one heater hose (the return) should be noticeably cooler than the other (the supply). That seems counterintuitive, but if the heater core is transferring heat, the outlet will be cooler, as much of the heat in the coolant will now be in the interior of the car. Check that the heater hoses aren’t crimped somewhere along the way.

If all that fails, cover about two-thirds of the radiator with cardboard on cold days to help the engine warm up faster. But don’t forget about the cardboard after the engine warms up, or it’ll overheat.

Dear Mike: I have been skeptical about the phrase “lifetime lubricated bearing” for the alternator, A/C compressor, water pump and other accessories in our cars. The alternator in my old Explorer seized after exhibiting a brief grinding noise at 100,000 miles. I wish there had been a way to lubricate it, because then it would have lasted much longer.

Could you explain how “lifetime lubrication” works on those accessories?

A: Ah, the myth of the lifetime bearing. In the case of things like U-joints and ball joints or tie-rod ends, when the lubrication fails, their life is over. Fortunately, at least most of the parts are available with grease fittings on them. In all fairness, the industry-standard sealed bearings used on stuff like alternators usually don’t fail until the rest of the vehicle is very worn out.

If you had taken the time to remove that alternator when it started to make noise, it would have been a matter of only 10 minutes and a few bucks to replace the bearing, saving you the cost of a new alternator.

Dear Mike: I have a 2002 Camry with 103,000 miles that needs new spark plugs. To give myself the best shot at getting the old ones out without damage, should I removed them while the engine be hot, cold or somewhere in between? Should I use penetrating oil, or will this not do any good?

A: Do it while the engine’s hot, or at least warm. And penetrating oil will have no effect — the seal at the spark plug’s base will keep the penetrating oil from penetrating very far. I put a tiny dab of anti-seize compound on the threads of new plugs.

Dear Mike: I drive a 2002 Hyundai, and after running the car for a while, I get good heat from the heater, but when I stop the car for a red light or a stop sign, the heater blows cold air. When I pick up speed again, the heater blows hot air. Do you know what causes this problem?

A: At idle, the water pump doesn’t move very much coolant through the heater core. Most small cars don’t make much hot air at idle, even after they’re warmed up completely. The only remedy is to hold the idle up a little with your foot.

Q: Is it OK to connect a 12-volt DC source to the cigarette lighter socket on my car in order to maintain the memory of various electronic components (i.e., radio stations, compass setting, etc.) while I remove and replace the car battery?

A: Yes. Actually, even a 9-volt transistor radio battery is plenty if you turn off the overhead light.