Automania/Repair & Maintenance

AUTO QUESTIONS AND ANSWERS FOR WEEK 31

by Bob Hagin

Q. We own a 1995 Mitsubishi Mirage five-speed with a 2.0 liter engine. It only has 20,000 miles on it. This vehicle, which we bought new, has a persistent and to us, dangerous situation. When we are driving it up a grade, the interior of the car fills with a strong sulfuric smell. The grade does not have to be very steep and we don't have to be going very fast. The smell lasts until the slope levels off. This doesn't happen every time but often enough to make it a health hazard. We have taken it back to the dealer that we bought it from several times but the mechanics there can't seem to figure out what is causing the problem. R.S. Redlands, CA

A. I haven't had a letter about that rotten egg smell coming from a new car for a couple of years now. I thought that between the oil companies and the car makers, the problem had been relegated to the annals of ancient automotive history. The problem can be caused by one of two things or maybe both - the fuel/air mixture may be too "rich" (too much gas and not enough air) or the gasoline you're using has too much sulfur in it. When too much fuel goes through the combustion process, the catalytic converter (a muffler-like device in the exhaust system) overheats and starts to change the minute quantities of sulfur that's in the fuel to hydrogen sulfide, which has that awful smell. Since the fuel delivery system in your Mitsubishi is computer- controlled, the problem is a glitch in the electronics somewhere that's allowing the injection system to pump in too much fuel. A factory field representative should be able to straighten it out. The other problem may be that the gasoline you're buying has a sulfur content that's so close to the legal limits that your Mitsubishi can't handle it. Changing brands usually eliminates the smell in that case.

Q. We bought a 1993 Chrysler New Yorker from an elderly woman whose husband died. It had very low mileage and it's really a beautiful car but it has one annoying problem that bothers me. When my husband drives the car around a corner, a slight rattling sound comes from the rear of the car. No one else seems to hear it and it never happens when someone is sitting in the back. My husband thinks I'm imagining things but I'm sure it's there. B.W. Baldwin, NY

A. The noise you're hearing is coming from the rear suspension coil springs and not from your head. According to a recent factory bulletin, the springs are moving around a bit when your Chrysler goes around a corner without a load in the back and they make the sound that you're hearing. The factory cure is to remove the rear springs and slip a long plastic "sleeve" over each end of both of them. I haven't been able to get a definite answer as to whether or not the factory will pay to have the job done so you'll have to ask a dealer. Over the years, I've come to the conclusion that women have much more acute hearing regarding things mechanical than men.

Q. I'm a college student and want to buy a sports car but, of course, I'm limited on money. I have found a 1983 Mazda RX-7 coupe that is in very nice condition except that the engine overheats and sometimes stops running altogether. I can buy it for a very reasonable price and I know a bit about auto mechanics but I've never worked on a rotary engine. Am I going to have a lot of trouble if I buy this car? H.M. Portland, OR

A. You won't have any trouble as long as you put a new or professionally rebuilt engine in it right away. The Mazda rotary engine is very touchy regarding heat. If the cooling system springs a leak and the engine overheats for more than a heartbeat, the "body" of the engine warps and is almost impossible to cure without major surgery. Buy the car if the price is really right but line up an engine first.