87 944T - head gasket question

[Raulg]

My Turbo is an 87 model with over 100K miles.

The exhaust manifold had a leak. The mechanic found the connections to cylinders 2 & 3 to be cracked. The header has been welded now but the car still sounds as if the exhaust were broken. There a small amount of smoke coming from under the cyl #1 exhaust connection.

I installed new exhaust gaskets, crush rings and made sure it is all tight. The engine idles fine but it sounds like a broken exhaust, it also sounds as if there were no oil at the valves.

Question: Could a bad head gasket do this? There is no oil mixed in the coolant or otherwise.
Please help.
Thank you
Raulg

[Techno Duck]

Does not sound like a headgasket problem.

Leaking exhaust usually sounds like a tapping sound. The headers on these cars are notorious for cracking around the flanges at the head and at the merge collector for each header. Did you guys smoke or pressure test the headers or only a visual check? The cracks at the merge collector wont be visible unless the heatshields are removed or smoked / pressure tested.

Also check the crossover around the wastegate connection and the CO test port.

Noisy valvetrain will sound like a clacking sound, likely one of the lifters is collapsed.

[Raulg]

Techno Duck;
The exhaust headers were smoke tested at first and the connectors to cylinders 2 & 3 were welded. The flanges were also found to be warped and had become slightly concave. I had the flanges "shaved" at a local shop to make sure they are flat now. They used some blue ink to determine how bad the flanges were.
I have installed new crush rings on the collector and even on the turbo side of the cross-over pipe.
There is also some exhaust coming from under the connection to cylinder 1.
When you say that a lifter may have collapsed, do you mean a broken valve spring? Would the only way to determine that be to take the head off of the car?

I will check the CO test port as you suggest.
Thank you for your help.
R.G.

[Techno Duck]

Sometimes the hydraulic lifters lose there prime and collapse. This can either be the port is clogged from being gunked up with varnish / dirty oil or just age. A broken valve spring is a possibility also. The lifters / valve springs can be inspected by pulling the cam tower.

[Raulg]

Techno Duck,
Thank you for your note.
In order to remove the cam tower, do I need to remove the distributor? and the timing belt housing?
Thank you
R.G.

[Techno Duck]

To get the cam tower off, the fuel rail, distributor and timing belt need to be taken off (belt can just be slipped off the cam gear). May consider just replacing the timing belt as its not much more work at that point.

Its a bit of a messy job (usually dumps oil all over the headers). Also taking out the allen head bolts can be a pain in the ass sometimes. You will need a long 6mm (if i remember right) allen head socket to reach the bolts inside the cam tower. The cam tower bolts are only torqued to about 15ft-lbs but they always require a huge amount of torque to break loose. I highly recommend undoing each one a little at a time until they are all lose, or you run the risk of stripping the last few you remove.. this is because the cam tower is under pressure from the valve springs / lifters. So best to loosen each a little at a time to remove pressure evenly. Also use a regular allen socket.. dont use a ball head which will likely strip the bolt or break with the torque required.

BTW, if you suspect a lifter has collapsed; sometimes it will pump up and go away on its own (may try driving the car a little to see if this works). Also might try one of the 'cleaning' techniques of adding seafoam, marvel mystery oil or adding a quart of ATF before your oil change. Sometimes this is enough to free up a lift. Might be worth a shot to save you some work. I only recommend adding ATF to the oil and letting it idle for a few minutes..dont drive it that way. Then change oil right after.

[Raulg]

Techno Duck,
The timing belt along with the balance shaft belt and hose are new. I replaced them recently while replacing the Turbo and balance shaft seals.
The car idles ok. I just can't figure out why the valves are so noisy.
Thank you for your reply. I will try out your advice this weekend.
I appreciate your time to reply.
R.G.

[kdjones2000]

The fuel injectors on these cars are notoriously noisy.

Are you talking about a mild "click click click" type sound, or a really significant "clack"?

The click sound is nothing to be worried about. Clacking would be collapsed lifters or possibly a valve spring.

Keith

[ryan951s]

Another possible cause for 'clacking' lifters could be the oil pressure relief valve in the back of the cylinder head. If it gets sticky and doesn't open/close as it should, one of two things could happen:

1) if it's stuck shut or won't open fully, it will restrict or completely cut off the oil flow to the lifters and they'll collapse and be noisy. Ask me how I know! ;-)

2) if it get stuck partially open, it will allow the oil to drain back out of the cam tower and the lifters could lose their prime as Techno Duck describes.

If you have the cam tower off, it's a very easy check. Remove the small bolt holding the relief valve in the head, and you will need to thread a bolt into the top of the valve to remove it (an m5 x 1.25 I think). Anyway, once you have the valve out, use a pick or a small screwdriver to see if the inside of the valve will open/close freely ... mine froze up after a winter of sitting with the head off the car.

Having said all of that, a collapsed lifter will be a significant 'clack' as Keith mentioned so should be pretty identifiable.

Good luck!

Ryan

[Raulg]

Ryan,
Thank you for your note.
The valves are pretty noisy. I haven't taken the cam tower out yet. I need to figure out how to do that. It looks like I have to take the distributor and the timing belt out, and the fuel rail, etc.

Would you know where I can get a diagram that shows the location of the oil pressure relief valve?
Another question: I replaced the timing belt within the last year, I have not driven the car since it isn't running well. It idles but when I let the clutch go it seems that it loses a lot of power as tries to stall. If the timing belt was not installed correctly, would the car still run? if so, could that be the reason for the loss of power when under load?

Thank you for your help.
R.G.

[Raulg]

I worked on the exhaust manifold connections, and they apparently sealed now, so no more exhaust noise.
The valves are still noisy. I noticed that after running the car idle for 5 minutes or so, some smoke comes out from somewhere below the exhaust manifold connections and also on the intake side, somewhere low.

I let the engine idle while the car was up on jackstands and tried to find where the smoke is coming out. I could not tell.

I did see the turbo pipe connections/flanges and they all looked sealed.
Is it possible the head gasket is letting exhaust fumes out?
How could I check if the head gasket is bad?
Thank you in advance for any advice.
R.G.

[nize]

forum search returns this;
Oil Leak - From Where?

[poulinsporsche]

get a haynes manual, it goes through the process of doing EVERYTHING youll possibly imagine, and they have pictures. i downloaded the 944 turbo haynes manual and use it frequently