Johnm1

Part of my next project beginning tomorrow will include replacing chain box cover gaskets. Looks like both leaking at bottom, and both tensioner feed lines are leaking. Also, both lines to thermostat are seeping so, going to replace those along with s-hose, while I have the oil drained.

How difficult will replacing the chain box covers be? I'm a little concerned about it.

Any problem with leaving engine drained for a week or so? Going to see if shop can repair lines next week, so might take a few days before oil is refilled.

Going to be doing a valve adjustment to, but probably won't get to it until next Sunday, so that's the reason for leaving oil drained for a week.

Ed Hughes

It is no problem keeping the engine drained. The covers aren't hard, it is just the access. A lot easier with engine out, or partially lowered even.

Peter Zimmermann

Unfortunately, the covers rarely leak. Your leak is probably originating on the back (forward) side of the chain box/housing, where the camshafts protrude into the chain box from the cam housing. There is an o-ring at that point which will leak, and requires cam/chain sprocket removal, o-ring replacement, and re-timing the cams. It's also a great time to replace the timing chain guides and update the tensioners (if the car is not already fitted with Carrera oil-fed type). Certainly not for the faint of heart. BTW; to remove the chain box covers you need to remove the muffler, then the rear engine tin.

theiceman

^ yup i have this exact leak on both sides

Pete can this be done with the engine in the car ?

Peter Zimmermann

Yes, sir! But, to replace the inboard, right side chain guides/ramps, you must remove the center engine mount "pylon". This means that you have to support the engine with a floor jack, undo and remove the outboard engine mount/spear bolts (one per end), then remove the pylon (four nuts at engine case) and spear as a unit. This allows access to the chain ramp bolts - you have to take them all the way out for cleaning and seal replacement.

Johnm1

Thanks guys. I'll try to post some pics tonight. Got muffler, engine tin, and ac bracket removed Sunday. The tensioner feed lines are leaking so bad it's hard to tell. The leaks at the cover areas really look like at the gasket for the covers and through the studs.

Peter Zimmermann

With the rear of the car raised and safely supported, slide under the car with a flashlight, and look up at the forward side of the left side chain box. You will probably have a path of oil running down across the chainbox from its upper, outboard corner. The leak is deceiving because wind passing under the car, while driving, will blow the oil onto the bottom of the cover. If you already have Carrera Tensioners, and the auxiliary lines (NOT the cam oil lines) are leaking where they attach to the covers, the tiny tensioner o-rings could be leaking - but I've never seen that. I have seen aux. lines, that don't have a support clamp, crack and leak.

Johnm1

Thanks Pete. Yeah, the car has the Carrera tensioners, but does not have the support brackets. The cam lines are leaking so much that oil is pooling in the recesses of the tops of the chain boxes. Appears to be oil path running down front inboard side of left box from top. It would not surprise me if cam seals are leaking. Not sure if I want to tackle that right now. No oil on ground from it.

Peter Zimmermann

Then I would advise to replace the cam oil lines, the auxiliary lines, add the appropriate clamps/brackets to the aux. lines, and drive it for a while. With luck, the cams were re-sealed when the Carrera Tensioners were installed (your car is an SC, right?), and the oil on the covers is all from the cam oil lines.

Just for grins, have you checked the base of the ignition distributor, perhaps some of your oil is leaking from that point.

Johnm1

So, you don' t think I should replace the chain cover gaskets while I'm there? Looks like distributor is OK. Oil definitely from cam lines, can see it drip and is flowing from top outboard of top of box. But distributor will be removed anyway.

Peter Zimmermann

Re; reseal the covers. It's hard to know because if (1) old stock paper gaskets were used without sealer (might not work long term), or (2) later technology gaskets were used with sealer (late gaskets are better when installed dry), or (3) if the mechanic didn't get the cover and chain box perfectly clean and degreased with lacquer thinner or MEK (non-oil-based cleaners must be used), or (4) old hardware, nylok nuts and aluminum sealing washers, were used (never a good idea, but it's cheap!); well, it's possible that the covers are actually leaking. If the Tensioner update was done with a kit, all new hardware and late gaskets should have been included.

Johnm1

thanks for the help Pete. Got some pics. I think it looks like cam seal, but there is so much oil from up above its hard to tell. Think I might just do cam and aux lines and cover gaskets and clean and see what it looks like.

Johnm1

here is a couple of pics from top of chain box at left side. There is more oil on top than the picture shows. Oil is pooling in the recessses at top. The out-board connection of the cam line is just as bad is the in-board. The tops of the tin near the connection is soaked. It makes me wonder if all of this isn't the cam lines...but, I would like to fix this the first time...if the gaskets are leaking.

Ed Hughes

That looks like a good candidate for a drop, and a little cleaning and upkeep.

Johnm1

Don't tempt me Ed...my fear is if I drop it, I may never get it back in. But, it is going to need to be dropped. The rear main seal is leaking and the oil cooler is leaking.