If my car consumes half qt every week.....

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Aug 13, 2002
...do I ever need to do an oil change? It is a 1979 Merc 280S with 2.8L carburettor engine, 6.5qt capacity. >300,000km. Using Shell dino 20w50. That means in 13 weeks I would have topped up 6.5qts of fresh oil.
I'd be doing an engine change!

Seriously though, when it consumes that much you could probably just change the filters on a regular basis and keep topping up with oil as needed. Eventually you'd need to get rid of the contaminents in the oil (such as fuel) so you should do a change at least once a year. At this point the engine probably wouldn't last much longer no matter what you do anyways.
By chance is the carb out of whack and leaking during shut down and or running very rich and fouling the oil ?
The turbines at work turn over about 20% of the "sump" volume per annum, which appears to be ample make-up to keep the oil state in the fit for service zone for THAT application. RBOTs look good, and the hydraulics are very clean when we strip them.

But we do have a super duper filtration system (sub 2 micron), and a centrifuge that pulls the water out of the system.

So I'd guess that if you got the particles out, that you'd never need a change.
Ooops, forgot to say that the one without the leakage/useage requires a change every 8 years on analysis.
23 years old & still refuses to konk-out...


Look....Scooby Doo spotted in Singapore!

p.s. Use to own a 1975 280S, but I fed it cheap $5 per 4qt noname oil. Kept topping up half qt every week, but engine died after 1 year w/o oil change & filter change. Not exactly died but gave off lots of blue smoke.
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