Cam Cover Bolt Oil Leak

[WIL35]

I had (and still have) an oil leak from one of the cam cover bolts, which I thought I would sort out. It works its way down to the exhaust to give that hot oil smell each time the car stops.

Took the cam cover off, meticulously cleaned all the surfaces and bolt holes, wiped the surfaces with cellulose thinners, carefully applied RTV sealant paying particular attention around all the cover bolt holes. Carefully refitted the cover without catching it on anything, torqued the bolts up evenly, left it at least 24 hours. Refitted the throttle bodies, connected the laptop, set it all up with nice low adaptives.

The sodding thing is still leaking from the same place!! It's the outer second bolt from the bulkhead. How come so much oil can work its way up the bolt, surely the cam cover doesn't get full of oil and isn't under pressure inside the cam cover? I even tried to put a little sealant around the top of the bolt. It still gets passed that.

Before I do it ALL again, am I missing something?

[Jhonno]

Sure the cam cover isn't cracked?

[rev-erend]

What you need to do is to stop that long cylindrical thin in the middle of each bank from spinning.

That is what is literally throwing the oil about.



But seriously, I'm sure most people just put more RTV around the bolt.

[Mr Cerbera]

rev-erend said:

What you need to do is to stop that long cylindrical thin in the middle of each bank from spinning.

That is what is literally throwing the oil about.



But seriously, I'm sure most people just put more RTV around the bolt.

Wowza Alan ! That is some clean valley you have there

[rev-erend]

Not mine .. I just grabbed a picture from the net..

Here is mine.. good old Rover V8.

[ukkid35]

WIL35 said:

The sodding thing is still leaking from the same place!! It's the outer second bolt from the bulkhead. How come so much oil can work its way up the bolt, surely the cam cover doesn't get full of oil and isn't under pressure inside the cam cover? I even tried to put a little sealant around the top of the bolt. It still gets passed that.

Before I do it ALL again, am I missing something?

Yes, it is under pressure, although the crank case breather should minimise that

The oil drainage path is at either end of the cam, and it is not at all restrictive, so even at high revs the oil won't accumulate in the heads (unlike my 928 engine - a weird potential failure mode)

I am really puzzled by your leak, it doesn't make much sense to me

1. Perhaps check whether the threads are damaged
2. Whether the bolt is the same length as the others (not including those holding throttle brackets)
3. With the cam cover off, perhaps check whether the bolts are bottoming out at the same depth

[TwinKam]

Try fitting a fibre washer under the head of that bolt

[notaping]

Are you putting gasket sealer all the way round the bolt holes, or just on the outside edge. If just the outside edge - oil could seep through to the bolt and travel up. Also, check the cam cover face with a straight edge and look for gaps or dings.

[WIL35]

Thanks for the responses! I thought I was being so careful with it, especially being my first time!

The bolts were replaced a couple of years ago when the valve clearances were done and it seems to torque down ok, although I am wondering about the bolt length now (thanks ukkid35), I might swap it for one of the others and see if the leak moves.

I was careful to put sealant around all the bolt holes, paying particular attention to this one. I even made sure I got any old sealant out of the threads on the cylinder head.

I tried a fibre washer before I decided to take the cover off. It took ages to file down to fit inside the recess, but even that didn't stop it. I'm wondering if there is a crack (as mentioned by Jhonno) inside the cover where the bolt tube goes. Without removing it again, which is fine apart from the hassle of setting it all up again, I don't think I can check much else.

For now, I will take the bolt out, give it and the recess in the cover a good clean with cellulose thinners, apply some fresh RTV sealant, then try it again.

I'm sure many of you have been through things like this before, lots of time and effort fixing something, take it for a run, open the bonnet......still not fixed

[Mr Cerbera]

It's not called "The Madhouse" or nuthin'