RAY: The reason they cost $71 apiece to replace is that there are tire-pressure monitoring sensors in them. If the sensor in the valve stem detects low tire pressure, it sends a wireless signal to the computer, which activates a warning light on your dashboard. And now the shop has to remove those sensors and put them in the new valves, which is why they can’t just throw a set of $5 stems in there and call it a day.
TOM: But I wouldn’t cut ’em off just yet (and, just to be clear, I’m referring to the valve stems, not your husband!). I’d try a penetrating oil, like Liquid Wrench, or some other product that’s supposed to break down the rust bonds.
RAY: Try one wheel at a time. Get the wheel lined up so that the valve stem is pointing down. Then drip or spray the penetrating oil onto the valve stem, and let it run down under the cap. Be careful not to spray the oil all over your brake rotors, because that makes the car very hard to stop.
TOM: You can apply the penetrating oil several times during a 24-hour period. The longer it has to work its way in there, the better its chances.
RAY: Then take two pairs of vise grips. Hold the stem with one pair so the rubber part of the stem doesn’t twist, and grab the rusted-on cap with the other pair and turn it.
TOM: I think it may work. Your dealer doesn’t want to take the time to do this, but you might as well give it a try.
RAY: Right. If it doesn’t work, you’re no worse off than you are now. And — needless to say — if you do get ’em off, throw them into the garbage immediately. Good luck, Jane.
Fog in car not a good omen for air conditioner
Dear Tom and Ray: I own a 2007 Chrysler PT Cruiser, which I purchased new. Since I live in Hawaii, air conditioning is a necessity. My PT has never given us any problems and has had all scheduled maintenance. Last week, while driving in a fairly heavy rain, I turned on the air conditioner, and a white mist began pouring out of the vent in the cabin. I turned off the AC, waited a while and tried again. Once again, the mist came pouring out of the vents. Since that time, I have no air conditioning. The blower works, but it only blows warm air. Before I take the car in to have it looked at, I thought I would ask you what you think might have happened. I don’t want to go in to get it fixed “blind,” and I don’t want to get taken advantage of. Can you help me get my “cool ride” back? Thanks! — Bobby
TOM: Must have been a cold front moving in from the Marshall Islands.
RAY: I suspect your evaporator has met the Chrysler Corp., Bobby — its maker.
TOM: I’m guessing that what you experienced in the car was fog. As the evaporator was gasping its last breaths, it released a large blast of refrigerant. That supercooled the warm air near the vents and condensed it, resulting in fog. If you were listening very carefully, you might have heard Gordon Lightfoot singing The Wreck of the Edmund Fitzgerald.
RAY: Your shop can confirm that your refrigerant leaked out by putting a vacuum on your air-conditioning system to see if it’ll still hold a vacuum. My guess is that it won’t. Then they can put some dye in the system and pressurize it, and figure out where it’s leaking from. But I’d bet my brother’s paycheck that it’s your evaporator.
TOM: To replace it, they’ll have to take apart the dashboard. So you’re looking at many hundreds of dollars to get your AC working again.
RAY: But on the bright side, you’re living in Hawaii, Bobby.
Send your comments or questions for Tom and Ray to: Car Talk Plaza, P.O. Box 3500 Harvard Square, Cambridge, MA 02238. Listen to them Saturdays at 10 a.m. on 91.3 FM or 88.5 FM. Visit them on the Internet at www.cartalk.com.
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