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Author Topic: clean oil in a diesel??  (Read 3949 times)

geoff

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clean oil in a diesel??
« on: July 23 2018, 10:11 »
I have an interesting condition with my 18 year old md 22l engine. About 5 years ago I changed the cam  belt and carefully retimed the engine using the 3x 6.5mm dowels to lock the crank cam and pump. Belt was then tensioned to the correct tension with a gauge. The engine ran fine apart from a very slight decrease in idle speed[ 50 revs maybe]. At the next oil change ,and every one since the oil is as clean as a petrol engine oil change. The engine uses a bit of oil but then it did from new[its a Volvo after all]. Any ideas why this 18year old has suddenly cleaned up its act ?   We have just got home after 2 months away and the motor didn't miss a beat . Geoff
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geoff

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Re: clean oil in a diesel??
« Reply #1 on: July 29 2024, 17:36 »
An update, since my original post the engine has had another cam belt change .All was very carefully retimed with pins in crank ,cam and pump. The engine continues to run very well ,still uses oil and still keeps the oil as clean as a petrol engine. It is now 25 years old and about 3000hrs. any ideas ?? Geoff
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Yngmar

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Re: clean oil in a diesel??
« Reply #2 on: July 29 2024, 18:19 »
How much oil does it consume? And how many  hours do you go between oil changes?
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geoff

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Re: clean oil in a diesel??
« Reply #3 on: July 29 2024, 20:34 »
Probably use about 2ltr  between changes and about 200 /250hr a year . Just got home after 9weeks wandering around a damp cold Brittany. Geoff
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Yngmar

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Re: clean oil in a diesel??
« Reply #4 on: July 30 2024, 10:28 »
That's not extreme amounts, although ours went from similar quantities back to using virtually no oil when I fixed the PCV valve that was stuck and vacuuming it out of the crankcase. Did you check that? One indicator was a little oil on the bottom of the air intake mushroom.

Our oil definitely was looking used after similar oil change intervals, but if it's not, why worry - just means your piston rings are still in good shape and you have minimal blow-by, or perhaps you poured in some extremely fancy oil?

Do you occasionally run the engine at full throttle (as you IMHO should to clear buildup and the mixing elbow) or never?
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geoff

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Re: clean oil in a diesel??
« Reply #5 on: July 30 2024, 12:22 »
I don,t really worry about it,but I do find it very odd. I have had diesel cars for years [and 5 previous boats] all of them made the oil as black as a witches wotsit . The pcv has given periodic grief but has responded to a whack. I cant complain about the engine , after 24years it still performs /starts as it should. Geoff
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