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'86 W123 200, OM617 non-turbo, bastard 5-speed; '95 W202 C250 Diesel, OM605 non-turbo, 5-spd man
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Discussion Starter #1
I have a 1982 240D, in which I replaced the engine with the five-pot 300D OM 617-engine. This engine has an oil radiator, while the 616 didn't (don't ask for an explanation - South Africa is the scrapyard of the world).

Now, after servicing my car, I used to fill the 240D engine with 6 litres of oil, which would bring the cold oil level to halfway between the lower and upper markings on the dipstick. For the 300D engine, I reckoned that 7 litres should do the trick, compensating for the bigger engine and new radiator. This brings the oil to overfull by 20 mm (0.8"). A day after its first drive, the oil indicates either empty, or below min, only to sometimes appear between min and max, or overfilled again two days later. :eek:Why is this?

Does the engine oil radiator have a thermostat, or no-return, which would only open when the oil is hot?
 

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1967 300
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There is a thermostat on the oil cooler that will prevent oil from going in if it is below a certain temp.

The oil cooler itself holds about 1 US quart. A turbo om 617 holds roughly 7.9 US quarts or i think 7.5 liters.

If you're checking the oil level right after shutdown, you're going to get an inaccurate reading since the engine pressurizes at least 2 or 3 quarts of oil throughout the engine. Wait roughly 20 or 30 minutes before checking the dip stick.
 

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'86 W123 200, OM617 non-turbo, bastard 5-speed; '95 W202 C250 Diesel, OM605 non-turbo, 5-spd man
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Discussion Starter #3
Thank you, areusche

Firstly, I never check fluid levels or tyre pressures after the engine has run, always before the first startup, so that's not the issue.

Secondly, does the thermostat allow all the oil to drain during a service? Where is it located in the oil radiator? Just put my paranoid mind to ease, if you please.
 

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1967 300
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Thank you, areusche

Firstly, I never check fluid levels or tyre pressures after the engine has run, always before the first startup, so that's not the issue.

Secondly, does the thermostat allow all the oil to drain during a service? Where is it located in the oil radiator? Just put my paranoid mind to ease, if you please.
No worries, I had a kid try and tell my friend once that his oil was low right after he drove it so I always ask.

The thermostat is located in the oil filter housing. I'm not sure if it allows the entire oil cooler to drain out, but when I replaced those rubber hoses, the entire unit drained out black oil so I'm guessing your answer is no.

If you want to put your mind at ease, get a new oil filter and exactly 7.5 liters of oil into the engine.

Or siphon a bit of oil back out of the dip stick with a long hose and pull it below the threshold.
 

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1984 300D
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The Thermostat for the Oil Cooler is inside the Oil Filter Housing.

When you pull of the Oil Filter Cap; at the bottom of that long tube is two the 6mmIDx10mmODx2mmWide O-rings (in the US these O-rings do not come in the with the Oil Filter). I believe the Oil simply leaks back into the Oil pan if they do not seal.
This also means that if you park your car say to go shopping the Oil will start to drain out of the Filter Housing when in fact most of it is supposed to stay in the Housing.
Also at the bottom of that Long Tube but inside is a spring loaded one way valve that is there to allow the Oil from the bypass section (the larger upper part of the Oil Filter) to pass through and the Valve is there to keep the Oil in the Filter Housing from drainging out quickily when you park somewhere.

So I believe that something amiss with the O-rings and that Valve could cause the Crankcase Oil level to vary.

In the Technical Data Passenger Cars Manual:
Oil Engine 617.952 initial fill (Engine Dry) 9.5 (I am assuming that is US Quarts)
When changing Oil and Filter- 7.5 Quarts.

So somewhere there is 2 Quarts old Oil left during an Oil change.

I know there is a pool of Oil inside of the Fuel Injection Pump/Governor because the Fuel Injection Pumps Oil Drian is abuout 3/8 of an inch higher than the cernter line of the Pump Camshaft.
The bulk of the rest must be in the Oil Cooler System.
 

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'86 W123 200, OM617 non-turbo, bastard 5-speed; '95 W202 C250 Diesel, OM605 non-turbo, 5-spd man
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Discussion Starter #6
Thank you all. I'll take a gander, come the next service.
 

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'86 W123 200, OM617 non-turbo, bastard 5-speed; '95 W202 C250 Diesel, OM605 non-turbo, 5-spd man
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Discussion Starter #7
The plot thickens...

:crybaby2:Now this is a little unnecessary...

Having established (again) that my engine oil level is correct, and that it neither leaks nor burns oil, my oil pressure guage is making havoc! Then the oil pressure drops to nothing for no reason, then it bounces up and down between 1 and 2. Oh, and of course, it shows max pressure before I've even started the engine!!:confused:

Is it the guage that's giving up the ghost, or is it the oil pressure sensor? Any idea how to check it/them? Is it something else entirely?

Thanks in advance. LOVE this forum.
 

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2003 Volvo V70 5 Speed
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There is no sensor for the oil pressure gauge, it's mechanical. There is an oil pressure line that leads up to it behind the cluster. If you suspect it's gone bad just grab a spare from a wreckers and see if anything changes.
 

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2003 Volvo V70 5 Speed
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P.S. DO NOT Drive it until you know that it's getting proper oil pressure.
 

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'86 W123 200, OM617 non-turbo, bastard 5-speed; '95 W202 C250 Diesel, OM605 non-turbo, 5-spd man
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4,275 Posts
Discussion Starter #11
Yeah, so the oil guage IS working. I had to add 1 liter of oil, which the dipstick failed to inform me of, so I guess it's back to post #1...:rolleyes:
 
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