Talked with a retired diesel mechanic at a parts counter last week and it changed my mind about synthetic oil in older engines

I’ve always used conventional oil in my 1997 F-150 because I figured synthetics would cause leaks in a high-mileage motor. This old guy, must have been 70, told me he switched his 80s Ford to synthetic at 180,000 miles and it ran another 100,000 without a single drip. He said the real problem is cheap gaskets, not the oil itself. I put in synthetic last weekend and so far no leaks. Has anyone else had luck with this on older trucks?

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1 Comment

charlie2694h ago

My 1994 Silverado with 220k on the clock would disagree with that old timer. I tried synthetic once, maybe eight years ago, and within a month I had a rear main seal drip that was bad enough to leave spots in my driveway. Switched back to conventional and it dried right up. I think it depends on the engine and what seals are already worn, not just gasket quality. Yours might be fine but I wouldn't bet the farm on it.