Q. I’ve owned, since new, a 1989 Chevrolet K1500 pickup truck with 350-ci engine and automatic overdrive transmission. The truck has had excellent maintenance and now has more than 272,000 miles. I have always used synthetic motor oil, and when changing the transmission oil and filter, I add an aftermarket additive.
Lately, at a stoplight with the transmission selector in drive, the check-engine lamp illuminates and the oil-pressure gauge shows zero oil pressure. Once the engine r.p.m. goes up, the pressure goes up to about 30 p.s.i. A heavier oil mitigates the problem.
Is this simply an engine showing its wear, or does the oil pump need replacing? Also, what kind of life can I expect from the transmission?
D.K., Barrington
A. More often than not, low oil pressure is due to worn engine bearings, not the pump. Another possible cause is a restricted pickup screen on the oil-pump pickup, but since you change your oil often, it is unlikely that there is debris or sludge on that screen. Our hunch? The engine is wearing out.
As for the transmission, we cannot even guess how much longer it will go.
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Bob Weber is an ASE-certified Master Automobile Technician, having recertified every five years since 1978. Address your technical questions about cars and trucks to him in care of Motormouth, 17717 Silcott Springs Rd., Purcellville, Va., 20132. Send e-mail, including name and town, to MMTribune@netscape.net. Answers will be supplied only through the newspaper
