Rocker cover gaskets

Brad

I've got a persistent engine oil leak on one of my 940s. I'm 99% sure it's coming from the rocker cover gasket. I have replaced this gasket 3 times in the last 18 months or so. The mating surfaces are absolutely clean. A new gasket will stop the leak for a while but then it will start again. I've used an Elring gasket each time. I've seen a few others have problems with leaks from Elring gaskets. Is there another brand that is better that I could try? This is for a B230 engine.

Major Ledfoot

How's your flame trap / crankcase pressure?
Is it leaking from the same place(s)?
No cracks on the cam cover?

Brad

I'll check the flame trap and related paraphernalia tomorrow but it was all cleaned a few months ago including the oil separator on the block. Can the oil separator be clear but still be no good?
It always seems to be leaking at or near the front and only on the exhaust side. The whole exhaust side of the engine block and head have a film of oil over them. The inlet side of the engine is completely dry. I know the engine is slanted so it could be running "down hill".
I had thought maybe the cam seal at the front was leaking and the oil being blown back but wouldn't I then be seeing oil on the bottom of the timing belt cover too?

Major Ledfoot

Brad If the the oil separator and flame trap are clear, and there's no leaks on that side, it suggests the leak's on the other side.
The oil cap 'o' ring / gasket is worth a look.
I agree - if the camshaft seal is leaking, oil would be all flung over the place.
The head-mounted distributor also has an oil seal of its own.
The hot side of the engine has many potential oil leak sources. These include the oil filter seal, the oil pressure switch, the joints in the auto transmission cooler lines, and the turbo oil pressure and return fittings at the block if applicable. You also have to rule out leaks from the power steering hoses and the rack since it's RHD.
You may have to pressure wash the hot side, then take it for a run and see where it's leaking.

Kingnuggie

my 740 had the same symptom, was a leaky front cam seal due to flame trap mesh holes being blocked, snuck a new cam seal in using occy straps to hold timing belt up, cleaned flame trap mesh and never leaked again

pigdog

I've found the elring gaskets are the best of all of them I only buy them now .
Something to consider that I've encountered a few times now ...... warped valve cover .
I've seen so many now , they pull down alright and the gasket mostly does the job but they don't seal perfectly and tend to seep out and leak

I always just use a thin layer of grey rtv both sides of the gasket

Brad

Thanks for all of the responses.
I did some more research via Dr Google and had a play around under the bonnet today. There were a couple more spots of oil on top of the oil filter again.
I found reference to a Volvo TSB that apparently states the rocker cover nuts should be torqued to 12.5Nm. I checked mine and they were all around 5-6Nm. They were also unevenly tight as I didn't use a torque wrench when I installed the gasket - just nipped them up to "about right". However, I also read a few stories of people snapping the studs so I gradually went up to 10Nm and that felt tight so I left it there. I ran the engine for a couple of minutes but didn't see any oil leaking from the gasket.
While I was fixated on the possible gasket leak the other night I failed to notice the oil around the oil filler cap. The worst coating was on the inlet manifold side so I didn't see it while poking around on the exhaust side of the engine the other night. It was a pretty significant leak so it's very likely the oil was running down the rocker cover then down the exhaust side of the engine. I put a new seal on it but the cap felt loose when I put it back on. The cap on my other 940 is noticeably tighter so this one might not be sealing properly. I'll see how it goes for a day or two.
I also did the time-honoured glove test. Video here [
The glove wasn't being sucked down but it wasn't being blown up either. The car is due for a service so I'll pull apart and clean the whole breather system. I did notice the little vacuum hose between the inlet manifold and flame trap is pretty soft so I'll get some replacement hose for that.
Thanks again guys. I'll report back in a couple of days. In the meantime I can turn my attention to the new coolant leak between the water pump and cylinder head...... 🙁

Anthony

As you’ve now tightened up the dome nuts sufficiently and evenly, I’d say the problem is solved.

Brad

After a few days of driving the car there is definitely a decent leak from the oil cap. Servicing the breather system and installing a new seal on the oil cap made no difference so I guess I need a new cap.

jamesinc

Yeah I had that problem once, tried everything, turned out to be the cap. I even tried flattening the seal surface out but it didn't help. A new cap fixed it.

Brad

Finally got back to dealing with this leak. Truthfully I'd been in denial about it and didn't want to deal with it. However the leak started getting worse about 2 weeks ago and the car was leaving a decent oil puddle on the floor so I had no choice. Last night I took off the rocker cover.
Spot the problem:

Close up:

The front exhaust side corner above the no. 1 exhaust outlet is the worst spot although the entire front edge of the gasket has separated. No surprise this is where the leak was coming from.
This is the second time I have had this happen and both times they have been Elring gaskets. I didn't bother telling FCP Euro about it last time but I think I'll let them know and see if they have anything to say about it.
Incidentally I looked back through the records and realised this is the fifth time in just under 3 years I've had to replace this gasket. My other 940 hasn't leaked a single drop for years.
I installed a new gasket and this time I put a small dab of RTV at the front and rear cam bearings as seems to be conventional wisdom on the internet. Let's see how long this one lasts.

nugget_940

I'll go off the back of Daves comment and say the cover is likely warped.
But also +1, I do usually run a thin layer of sealant as well around the gasket before installation.

Brad

Would a warped cover screw up a gasket in this way? I was thinking maybe I had done something wrong during installation.

Major Ledfoot

Nah, looks like a defective gasket. It looks like the two halves have split.

jamesinc

@DecimalDuck split gasket strikes again!

This failure has come up on Oz Volvo a number of times now. Anecdotally I have had better results with Victor Reinz gaskets and worse results with Elring, although other Elring gaskets seem to be fine.

I have taken to smearing a film of Permatex no. 3 all over both sides of the gasket.

Brad

FCP got back to me regarding these gaskets. They claim they are not aware of any known or inherent issues with them. The offered to exchange it if I sent the old one back. Wasn't worth me paying the postage to send it back so I declined. Next time I'll try a different brand although I still have 2 Elring gaskets in my stash.
So far this new one isn't leaking but It's only been about 3 weeks....