My dad has noticed lately that his 92 300D has been using oil recently. Like a quart a week. The car does not smoke visibly. I was skeptical of his turbo as there was some slight left to right shaft play when I did the waste-gate actuator swap. However I have not had a chance to look at it yet (he lives in a different city) but he called the other day and said he didn't have brake booster assist and the car would not shut off with the key.

Can the vacuum pump diaphragm going bad consume oil on an OM602?

(I realize on a diesel there is no manifold vacuum)

__________________
68 280SL - 70 280SL - 70 300SEL 3.5 - 72 350SL - 72 280SEL 4.5 - 72 220 - 72 220D - 73 450SL - 84 230GE - 87 200TD - 90 190E 2.0 - 03 G500

Nissan GTR - Nissan Skyline GTS25T - Toyota GTFour - Rover Mini - Toyota Land Cruiser HJ60 - Cadillac Eldorado - BMW E30 - BMW 135i

Consume? -no.

no vacuum system exhaust goes directly to cylinders. The exhaust from the pump does add to crankcase air volume though - otherwise perceived as 'blowby' when you take the 730 cap off.


Not sure if it could pump it to a different location though if the right valve failed.

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I don't believe there is a diaphragm in the 602 pump, I believe its a piston style. Either way, they don't use oil. Its a coincidence that the pump went out at the same time. If its the original pump he should stop driving it. There is a good chance the pump has\could grenade and take out the timing chain.

__________________
2004 F150 4.6L -My Daily
2007 Volvo XC70 -Wife's Daily
1998 Ford F150 -Rear ended
1989 J-spec 420SEL -passed onto its new keeper
1982 BMW 733i -fixed and traded for the 420SEL
2003 Volvo V70 5 Speed -scrapped
1997 E290 Turbo Diesel Wagon -traded for above
1992 BMW 525i -traded in
1990 Silver 300TE -hated the M103
1985 Grey 380SE Diesel Conversion, 2.47 rear end, ABS -Sold, really should have kept this one
1979 Silver 300D "The Silver Slug" -Sold

First of all, I wouldnt assume a bad pump, a vacuum leak is more likely. If the pump was gone, you'd probably hear the shrapnel rattling around the timing case.

Not only should there be no detectible blowby, there will be a slight vacuum in the crankcase under most operating conditions.

Especially with the turbo, its important to be sure that the engine is well sealed. If you have a leaky pan gasket, valve cover gasket, vent grommet, front or rear mail seal, oil cap, or dipstick o ring, the turbo will draw air and oil right out of the engine. (Again, you will have vacuum, not blowby in a well running motor)

I don't think I've ever seen a Mercedes diesel with a vacuum in the crank case. There will always be blowby.

__________________
2004 F150 4.6L -My Daily
2007 Volvo XC70 -Wife's Daily
1998 Ford F150 -Rear ended
1989 J-spec 420SEL -passed onto its new keeper
1982 BMW 733i -fixed and traded for the 420SEL
2003 Volvo V70 5 Speed -scrapped
1997 E290 Turbo Diesel Wagon -traded for above
1992 BMW 525i -traded in
1990 Silver 300TE -hated the M103
1985 Grey 380SE Diesel Conversion, 2.47 rear end, ABS -Sold, really should have kept this one
1979 Silver 300D "The Silver Slug" -Sold

Definitely a vacuum in any turbo engine. Maybe different in NA engines due to the config of the breather, but I've got to think it's the same off-idle. Vacuum aside, If you have an opening anywhere in the engine envelope, it's a direct path between the intake and atmosphere via the breather tube.

Note: On my '84 TD, when the vacuum pump's cam-bearing failed, I heard no unusual noises - even after I reached my destination and discovered I had no power-brake and the engine wouldn't shut off. If I had driven it much further, the bearing-lever would have disintegrated. Then I probably would've heard something as my timing-chain self-destructed!

Happy Motoring, Mark

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DrDKW

There are those inline fuel looking filters in the vacuum system. I thought it was possible at least on a W123 for engine oil to wind up in the vacuum system.

As I stated in the original post I realize the engine itself isn't consuming the oil i.e. burning it. I didn't know if the pump could suck oil into the vacuum system.

I've sort of gotten my answer. Thanks for your help.

__________________
68 280SL - 70 280SL - 70 300SEL 3.5 - 72 350SL - 72 280SEL 4.5 - 72 220 - 72 220D - 73 450SL - 84 230GE - 87 200TD - 90 190E 2.0 - 03 G500

Nissan GTR - Nissan Skyline GTS25T - Toyota GTFour - Rover Mini - Toyota Land Cruiser HJ60 - Cadillac Eldorado - BMW E30 - BMW 135i

This what I was asking.


This was my answer.

__________________
68 280SL - 70 280SL - 70 300SEL 3.5 - 72 350SL - 72 280SEL 4.5 - 72 220 - 72 220D - 73 450SL - 84 230GE - 87 200TD - 90 190E 2.0 - 03 G500

Nissan GTR - Nissan Skyline GTS25T - Toyota GTFour - Rover Mini - Toyota Land Cruiser HJ60 - Cadillac Eldorado - BMW E30 - BMW 135i

As a side note, the little filters you see in the w123 system (and others) are to prevent oil from being sucked through the system if the diaphragm in the shut off actuator fails.

__________________
2004 F150 4.6L -My Daily
2007 Volvo XC70 -Wife's Daily
1998 Ford F150 -Rear ended
1989 J-spec 420SEL -passed onto its new keeper
1982 BMW 733i -fixed and traded for the 420SEL
2003 Volvo V70 5 Speed -scrapped
1997 E290 Turbo Diesel Wagon -traded for above
1992 BMW 525i -traded in
1990 Silver 300TE -hated the M103
1985 Grey 380SE Diesel Conversion, 2.47 rear end, ABS -Sold, really should have kept this one
1979 Silver 300D "The Silver Slug" -Sold