Q: My husband and I have an ongoing dispute. Don't worry: No matter what, your answer won't precipitate a divorce! My question, which is for all the marbles: Does a car cool off more quickly if one opens the windows while waiting for the A/C to kick in, even in the heat of the summer? I say that any breeze or air flow is better than no air flow. (However, I guess there is a little air flow from the vents before the A/C kicks in, but it doesn't seem to cool the car down as quickly as fresh air.) Or, as my husband avers, is it better for me to melt onto the leather seats for the five minutes before the A/C kicks in because opening the windows and letting in the hot outside air will just make the A/C less efficient? Again, the happiness of our marriage is not resting upon your answer but, well, I'm obviously right, right?
C.W., Norfolk, Virginia
A: Chill. You are not obviously right, however you are partially right. Running the air conditioning draws outside air into the cabin creating positive air pressure, so opening the windows a crack allows the hot air to be replaced by cooler air. But, better yet, setting the HVAC system to recirculate, or max A/C, continuously re-cools the air that has already been cooled. While you guys are hot, it may be time to kiss and make up.
Q: My wife has a 2014 Jeep Wrangler (manual transmission) approaching 70,000 miles. She takes good care of it but just recently had some issues. She was driving on the highway and the Jeep convulsed into jerky movements. The Jeep wouldn’t accelerate past 30 mph, even though she shifted into higher gear. We got it to our mechanic. He scanned the computer for codes and saw that timing readings on both banks were reading correctly. He cleared the codes, test drove it multiple times with no problems at all, and none of the codes have returned. We cannot diagnose the root cause, but the Jeep seems to be running fine. We’re stumped!
B.M., Naperville, Illinois
A: Stumped? Hey, he fixed it, didn’t he? Most people are stumped if the technician fails. They send me letters.
Q: I recently bought a 2002 Honda from a service station. They said it was in working condition and would stand behind the transmission and engine for three months. The problem seems to be that the air conditioner works when the car is moving but when we are idling, it blows hot air. I brought it back for them to service and showed them your column about the rubber tube being clogged. They said they checked it, but the car is still doing the same thing. Am I facing a bigger problem? I would like to be aware of it and take care of it.
C.O., Skokie, Illinois
A: A clogged drain hose gradually reduces the A/C efficiency, but once the evaporator coil icing condition melts, the A/C is restored. I think the problem may be a bit more complicated. The A/C condenser, which sits in front of the radiator, may be restricted from bugs and leaves or the electric fan may be malfunctioning. In either case, air from driving down the road could be sufficient to cool both the condenser and radiator adequately. Not so when you stop. But I can’t rule out a bigger problem.
