Automania/Repair & Maintenance

Auto Questions And Answers For Week 43 Year 2001

by Bob Hagin

Q. My husband and I own a 1995 Ford Windstar with a 3.8-liter engine. We've gotten almost 90,000 trouble-free miles on it and plan to get another minivan in the next year or two. We are completely satisfied with this car and would like to get something comparable. However, we would like to save gas and ensure good road traction and therefore would like to find a minivan that is also a hybrid and has all-wheel drive. Do you know of any auto makers who might be going in this direction in the next couple of years?

A. Try one of the hybrid sedans that are being produced and you'll see why they get such good fuel mileage. They're very light in weight and produce comparatively little rolling resistance. To use this same technology on a minivan-sized vehicle, the gasoline engine would have to be considerably bigger and the electric motor would have to be bigger yet. And since all-wheel drive produces more rolling resistance that two-wheel drive, the units would have to be even bigger and more bulky. The current crop of hybrids are money-losers and weak sellers for the companies that make them. My feeling is that they're made to provide a positive public image for the companies involved. To tool up for a full-sized hybrid minivan that would have a limited market would probably cost the heads of the company executives that approved it. So to answer your question more succinctly, I haven't heard of any hybrid minivans in the offing through the grapevine or in the trade journals.

Q. The engine in my 2000 Chevrolet Silverado knocks for several seconds when it's started cold. I bought the vehicle new and it now has 27,000 miles. I've had the dealer keep the vehicle overnight and duplicate the knock. The dealer says the problem is common to the 5.3-liter engine and Chevrolet Tech Assist says a repair is pending with parts availability in December 2001, but no tech bulletins are currently available. Apparently the noise is caused by piston slap, which Chevrolet says is not detrimental to the engine due to the use of skirtless pistons. Have you heard of this problem and do you have any recommendations as to how to resolve the problem?

A. I've never heard the ailment myself but the internet turned up lots of similar complaints. If your oil pressure light goes off instantly when you start the engine, the problem probably won't be oil pressure bleed-off in the oil filter, but it couldn't hurt to change the filter with one of a different type. Piston slap is a problem in lots of late model engines and I've seen it caused by piston rings that have become stuck in their ring lands from carbon gum-up. If the original Chevy pistons slapped from day one, there's a flaw in their design and the only cure is to replace them which would be a very expensive recall for General Motors.

Q. I have an '86 Toyota 4Runner with a four-cylinder fuel injected engine and 273,000 miles on it, about 70-percent being freeway miles. I follow the maintenance schedule carefully and have not had to make any repairs on the engine. For several years in the summer when it's around 80-degrees, it has been pinging when I drive at 55 and above or when I'm accelerating. Tune-ups have had no effect. The mechanic suggests using a higher octane fuel to see if it makes a difference. The manual calls for 87-octane, which is what I use.

A. There's not too many things that cause pinging at speed. Have the ignition timing checked at high engine speed to see if it's advancing too much. Another problem could be overheated combustion chambers, which could be a cooling problem or even carbon build-up. The latter can be cured chemically without an engine teardown.