Quote:
Originally Posted by paul2748
What's the truth to the old saying that you should not use a detergent oil on an engine that you don't know the condition of i.e. sludge, deposits, etc.
Some people say it can loosen up the deposits and clog passages.
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Although I've tried it several times, I've yet to see any sludge loosened by modern oils. That stuff is so dense and settled/attached that only scraping and serious disassembly and cleaning will remove it. I ran a high mileage flathead 3000 miles burning a qt of 15w40 high detergent diesel oil every 200 miles (during summer) and the sludge wasn't affected at all. About 1/2"+ deep in the pan and large amounts in the valve chamber. Stuck like glue.
Terry
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"It don't take but country smarts to solve the problem" (Smokey Yunick)
'41 Merc Town Sedan / 260" 8CM engine
'66 Fairlane four door / "warmed up"
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