Blow-by or other problem?

technics1974 Part of things Posts: 890	Blow-by or other problem?technics1974 @technics1974
	Jun 8, 2011 13:22:57 GMT Select Post Deselect Post Link to Post Back to Top
	RE: 1985, W123 230E with 103k miles on the clock. I was finding oil deposits around the base of the oil filler cap. I replaced the rubber seal that fits under the cap, the problem persisted. I fitted both seals (one over the other), the cam cover is now dry. However, this morning I noticed that the cam cover gasket has passed oil towards the rear offside corner of the cylinder head. The engine is obviously suffering from excessive crankcase pressure. The vent pipes that extend into the air filter housing are clear and there is evidence (oily deposits) within the air filter housing to suggest that the system is venting. The engine is in good condition. Oil pressure when cold is full 3 bar and just over 2 bar when idling and hot. The engine pulls well and doesn't smoke. There is no excessive valve gear noise. What could be causing the high crankcase pressure? I understand that usually it is caused by worn piston rings but I would expect related engine problems if this was the case. How can I provide additional crankcase ventilation? Any ideas?
	1985 Mercedes W123 230E - 5 speed manual & 2011 BMW F11 520d Touring - 8 speed automatic.

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djefk Part of things Posts: 844	Blow-by or other problem?djefk @djefk
	Jun 10, 2011 12:15:53 GMT Select Post Deselect Post Link to Post Back to Top
	I've had this prob before on a couple of different cars: the basic prob is that after 100k miles your bores now have some wear on them. if you don't want to strip and rebuild the engine then I would fit some sort of catch tank into the cam cover breather to stop your air filter getting contaminated and put up with a slight leak from the cam cover. This is of course assuming there isn't an actual crank case breather that is blocked- you should check out your Haynes manual to see if there's one you don't know about first
	BMW 2800 CS - the full story here: retrorides.proboards.com/index.cgi?board=readersrides&action=display&thread=72391

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BenzBoy Probably posted too much Posts: 17,940 Club RR Member Number: 7	Blow-by or other problem?BenzBoy @benzboy Club Retro Rides Member 7
	Jun 10, 2011 13:46:09 GMT Select Post Deselect Post Link to Post Back to Top
	I'm going to stick my neck out and say that it won't be bore wear on a 100k mile M102 engine, assuming that it's been looked after. It could be, but I would say it's very unlikely. Like djefk said, check the breather system for blockages. I would make sure the PCV valve is working properly. It might even be worth getting a new one.
	Last Edit: Jun 10, 2011 13:48:02 GMT by BenzBoy 1975 Mercedes-Benz 200 1989 Nissan Patrol OM606 conversion 2015 Volkswagen Caddy Maxi

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