oil leak question
 

ok simple question but the obvious answer doesn't make sense. Its an 89 turbo. The leak appears to be coming from behind the timing belt cover which would point to a seal. It has a new seal in it and it still leaks oil but only seems to leak when you load it with boost to launch the car. i know sounds like a dumb question but its just not making sense to me with this car also!


thanks
Mat
FTWMOTORSPORTS

Done the head gasket recently? If so, did you forget the RTV at the block/timing plate union?

not to sure this is how we received the car and the customer purchased the car as it sits. so neither of us are to sure as to what has been to this engine. but that would make sense, so if it appears to be leaking from behind that cover then this could be a possible solution?

Well, there are only a few possibilities. A shot seal, a misinstalled seal, a leaking valve cover gasket (usually due to old seals or not applying RTV where the #1 cam caps mate with the head) or a leak between the head and the block (the area I mentioned previously).

Diagnosing is obvious enough, pull the cam gears and the upper, rear timing belt cover, check for oil. If it's up as high as the cam shafts or the valve covers I'd just go ahead and replace the seals AND the valve cover gaskets.. they're cheap and if they're stock (which sadly you can't really test for) they should be replaced.

If there is some oil along the bottom of the plate, but not higher it's likely to be the union of head/lower, rear timing plate and block. This can be a little harder to diagnose. I'd clean the hell out of it, put the cam gears and timing belt back on (but leave the upper front timing belt cover off), run for a few minutes at normal operating temps and then check for any new oil... use UV additive if you like. If you find no new oil take it for a short drive.

what is prolly the most common or are these all about as common. i have replaced the front seal on the crank cause thats where it appeared to be coming from, but i still have the leak. i will pull the cam covers off and clean like crazy and go from there. oh just remembered that the valve cover was loose when i first got the car here i tightened all the bolts to spec. should that still be of concern?

Most common are the camshaft seals ftwmotorsport, I should know the answer to this cre , I've done it enough times; What exactly is this sealing?
http://i17.photobucket.com/albums/b5...EALPACKING.jpg

Unfortunately none are really uncommon. In order I'd check: valve covers and cam seals (seriously, just replace them and don't forget the FTV at the #1 cam caps), then the oil pump drive seal, then the lower rear timing plate.

Cam seals and cover leaks will be fairly evident as they're the only two which will leak a decent amount of oil behind the upper rear timing belt cover (the black plate).

If the head hasn't been removed it's VERY uncommon for oil to leak from between the head and the lower rear timing plate... unless you're VERY unlucky (raises hand) I put too little on or it didn't cure or something, it blew out a few months after doing the HG on my personal car. If the head was pulled and the RTV was not used though it WILL leak.

Did you replace the valve cover seals? Did you over torque them (only 22 INCH lbs, NOT ft lbs!!!)?

As I said before, I'd pull the upper plate, clean out behind it thoroughly, replace the cam seals and valve cover seals, reassembly, clean the rest and run it... use some dye and as long as you're paying attention you should see where the leak is quite readily if you didn't just fix it.

I would have to say that I've seen more leaking valve covers than cam seals myself.


IIRC, there are two concerns in the area where the packing is used: the seam between timing plate and block and the lower clamping force between head and timing plate due to the low area for the mating surfaces.... Always seemed odd to me that it would leak as bad as it does there though.

well we figured out the cam seals were bad so i put new ones in. any other ideas as to what to check next. it has new cam seals and front crank seal! hoping someone can shed some light in the next few minutes!

thanks
FTW Motorsports