Strange oil leaks

[Chainsawdaz]

Hello everyone, I am looking for some advice on what could be the possible cause for multiple oil leaks on my 240 b200e engine, engine has 130k miles on it.

Had the car for 3 months now, was fine when I got it, about a month later I gave it a service, new oils everywhere, fuel and oil filter, new cambelt, new oil separator and cleaned the flame trap and tubes, about a week after that is when the oil leaks started.

First it was at the rear of the engine on the bell housing so I thought ok I'll change the rear crank seal, at the same time I changed the seal cover gasket and the sump gasket (was hard to do in situ) leak didn't go away and then at the same time the front started leaking so again I was like no problem I'll change the 3 front seals, same time also changing the gasket on the seal holder for the crank and distributor shaft at the front, also changed the cam cover gasket. Leaks at front and back still persist.

Today I just took the gearbox back out thinking I have done something wrong with the seals despite pushing them in a few more mm and cleaning the old gasket off etc, new rear seal is nice and dry so leak is still coming from somewhere else. Top half of engine is nice and dry too so doubt it's a headgasket, no other blown head gasket symptoms, also did the oil filler cap trick to check for blowby and it seemed fine with a good suction nothing blowing out or smoke or anything so I'm positive it isn't a crankcase pressure issue.

Really lost for what's causing this sometimes want to just throw a sledge hammer at it , MOT in 2 weeks and I know they can fail based on oil leaks, car isn't really used much longest trip it had was 60 miles to the volvo600 event, any help and advice would be appreciated

[Clifford Pope]

I'd suspect the camshaft cover, as it's one of the things you disturbed.
I've always found it very difficult, ie next to impossible, to get a good seal here.
The gasket has to do very sharp nips on the uprise over the bearing caps. It needs to be very firmly bolted down, but at the same time I'm always scared of cracking the cover.

Modern gasket cements - blue hylomar etc - don't really "wet" oily metal. The oil always seems to find a way of seeping through. Once through, it runs along the seam as an invisible trickle, and then runs down at the front or else down the back of the blockand down the bell housing.

I've found the only thing that works is the old-fashioned red hermetite if you can get it. The oily gritty stuff with some filling power that sets sort of semi-hard, not the synthetic silicone kind.

As an MOT expedient, go round the engine with a rag just before and clean it up.

[Chainsawdaz]

Thanks for the suggestion, I will try and source some of that stuff and will redo that gasket, I can see what you mean I remember when changing it that it didn't seem right over those semi circles lol

[Stephen Edwin]

My memory.

I thought red Hermetite was for water sealing gaskets, green for oil sealing?

[Bob Meadows]

I believe Hermetite Red has been discontinued some time back: ~ Hylotyte Red is apparently the new formula (oils & fuels)
Bob

[Chainsawdaz]

It seems to be that way, can't find many results for hermetite red however plenty of results for hylotyte red

[dingov70]

Just a touch of clarification regarding oil leaks & MOT , It is an advisory UNLESS the patch of oil exceeds 3" ( or 75mm ) over a 5 minute period . Thats a pretty substantial leak !
I would degease 7 wash off all oily deposits & run engine at home with cambelt cover missing , see what shakes loose . allow 30 minutes plus to achieve results

A neat trick from the aero world , glue silk ( or cheaper cotton sewing thread ) using superglue to metal surface of head & then fit cam cover & new gasket . Glued thread bites into gasket enhancing seal . In aero engines the thread is the actual gasket

[AlexO]

Originally Posted by dingov70

Just a touch of clarification regarding oil leaks & MOT , It is an advisory UNLESS the patch of oil exceeds 3" ( or 75mm ) over a 5 minute period . Thats a pretty substantial leak !

That's interesting Dingo. I had a fail this year on an oil leak that was larger than 25mm in 5 minutes. I queried it and got the old shrug and "new rules" chat. Are you quoting the new rules or is this info taken from last year's rules before the change?

[Paul240480]

I used this stuff on recommendation on here when I did the sump seals on my old 850. No leaks after refitting. Good stuff. Smells a bit mind.
Good luck.

[Clifford Pope]

Originally Posted by dingov70

Just a touch of clarification regarding oil leaks & MOT , It is an advisory UNLESS the patch of oil exceeds 3" ( or 75mm ) over a 5 minute period . Thats a pretty substantial leak !

It depends entirely what the surface is it's leaking on to.

A dry concrete floor will absorb lots of oil before it ever spreads more than 3".
One drop on a mirror-smooth polished surface will spread a foot in no time.
One drop will spread a molecule thick over a pond in seconds.

Unless the MOT examiner has a special test tray it's a meaningless experiment.


A few weeks ago I got an advisory for an axle pinion oil leak that didn't drip at all - it was absorbed by the muck on the axle casing.