Oil Leak Between Engine and Gearbox

[craigwalton]

There has been a slow oil leak resulting in drips from around the sump drain plug. The last couple of oil checks have revealed a small amount of white gunk, suggesting moisture. I jacked up the car to take a closer look today and the source seems to be between the engine and gearbox, at the height of the sump join. Not sure if its engine or gearbox oil.

The rear left corner of the sump is the big rusty thing shown on the right of the photo (one of its bolts visible) and the bottom left of the gearbox shown on the left of the photo. Note the rubber thing flopping around in between.




It was wet at the lowest part of the gearbox, but I suspect this is not the source, but rather the oil was running down and collecting here:


Another thing I spotted was that RHS wheel driveshaft had this yellow pressed steel plate - is it meant to be exposed like that? The LHS has no visible yellow part. It's higher up than the sump and looked ever so slightly oily.


Finally, I tried to clean up a little. The rubber strip really seems out of place to me - it is still secured but where is it meant to be?


Has anyone got any advice on tracing the source of this leak and if it looks like a common leak? Thanks in advance!

[bengould]

Might just be me out in the sticks with rubbish internet but all your image links are not showing.

Ben

[craigwalton]

Thanks for the heads up Ben, seems the images on my google drive via driv.es were not showing for users other than me. Have changed the way they're linked to and I hope it works now!

[james butler]

i cant see them either.
first thing i would check is all the sensors in the head tight, is your rocker cover gasket leaking, have you checked your levels and noticed any of them going down?
best thing to do is give the entire area a good clean down with a jet wash then run the car up to temp and see where it leaks from.
plus smell it. compare that smell with the oil on the end of your dipstick, gear oil has a funky smell totally different from engine oil so you should be able to tell the difference

[james butler]

oh scratch that i can see them now

[mark1gls]

As james butler says, smell the oil and you can then tell if it's gearbox oil or engine oil.
Have a good look around the oil sensor above the oil filter and lift the rubber boot, check oil filter housing and WUR if you have one oil will find it's way to where you have pictured from above as I have the same problem but mine is leaking from my dissy shaft as I'm missing a seal.
A guess it will be engine oil and possibly from the sump gaskets, try nipping up the sump bolts just a little bit more to see if that helps.

Gearbox if fine and normal to have just one cover showing, I've not see a yellow one before as usually they are green?

[craigwalton]

Thanks for all the pointers! Unfortunately it will be a while until I can get my hands on pressure washer. Could not pick up any smell on the leakage (I had a bottle of gear oil and engine oil to compare to). Not noticed engine oil level dropping any faster than usual, coolant maybe just. I checked rocker cover gasket (rubber) and it looks good to me. So I cleaned up all around that area with the cover off including the cover, nuts and studs. After 5 min of engine running, still dry. After a couple of hours of doing nothing, it feels oily again. Perhaps leak path is from the inside wall of the rocker cover (gets wet when running) and then finds a way out given some time? All 3 photos are of suspected leaky corner.





Discovered another worryingly damp area on the rear right of the engine block, just below the head gasket. Coolant slightly low, occasional white gunk in oil, hmm. However, if the leak is from the rocker cover, the oil would find its way to this area, but it's worrying that the head is dry-looking. All cleaned up now so will re-evaluate tomorrow. The photo shows the engine mount on the right, block in the middle, with head and exhaust above.


I'll try checking the various sensors and areas suggested now that the thing is a little cleaner. Will report back with findings! Still runs lovely though.

[mark1gls]

The leak/oil at the back of the block is from the rocker cover gasket as mine has leaked there before and oil over the back of the block just like yours. The other place a leak can cause the some affect if the cam shaft seal, if you remove the cam belt cover and have a look at the seal, clean it up and look for any leaks.
Your rocker cover may be very slightly bent in that corner from being over tightened and that is why you can seal it very well.

Old picture from when I remove my exhaust manifold and you can see what happens

[craigwalton]

Thanks Mark, reassuring to know it's likely not the head gasket. Here's what the right hand side of the head looked like, under the cam belt cover before I cleaned anything. So it's definitely a possibility that it's leaking too.


Will take a closer look at the camshaft seal hopefully tonight. If the rocker cover were bent, what could I do about that other than buying a new one? Get something flat to judge level and try bending it back...? I haven't personally taken the cover off before the leak but I'll be sure to look up the torque values to avoid over tightening.

[mark1gls]

May be worth giving it clean up, a rag and some petrol/thinners/white sprit will clean the oil off then you should be able to see where the leak is.

If you do change the seal the hardest thing I found was undoing the bolt at the end of the camshaft, I removed the cam cover, placed a bit of wood along the head then put a trolly jack bar through a hole in the cam shaft cog to stop it moving then loosened the bolt. Marked and lined up the engine timing marks then removed the cam belt, remove cam shaft (make sure you losen the bolts in the correct order) BE VERY CAREFULL NOT TO LOSE THE WOODRUFF KEY from the cam shaft when you remove the cog.
I did read somewhere about oil seeping past the end cap so I had some blue hylomar so I did it any way.
Pictures from a head rebuild for the golf but I did the same on Mk1 Scirocco with the engine in so it is possible.

You can see where I put the Hylomar


New seal and cap fitted.


Picture of woodruff key


New camshaft seal
http://www.eurocarparts.com/ecp/c/Volks ... af3&000426

If your cam belt tensioner plastic?
If so you may be better with a metal one?
http://www.eurocarparts.com/ecp/c/Volks ... c98&000091

Like this.

[craigwalton]

Cheers for the tips and photos Mark! Will refer back to them if I need to change camshaft seal. Yep, tensioner is plastic. What advantage would metal one have over seemingly working plastic one?

I'm still keeping an eye on the leak to determine for sure where it's coming from. There's definitely 2 leaks: one from rocker cover gasket and/or camshaft seal; one from sump gasket or gearbox on left hand side. Both are reassuringly slow however. Will post back if and when I fix either leak.