It seems like I have an exhaust leak from where the manifold meets the head on cylinder #1. I replaced all of the mounting hardware and gaskets a few months ago when I did a head gasket replacement, but since then I have noticed it was getting smellier and finally discovered smoke coming from this area, and some discoloration on the manifold flange. I checked the torque on the mounting nuts and it seems to be fine. What can I do about this? I'm supposed to drive 5 hours to 944Fest in a couple days, but I'm pretty sure I would succumb to CO poisoning long before I get there in this state. Is there some sort of sealant that can handle exhaust temperatures I could put on? Should I try over-torquing a little bit?

 

they should be pretty tight.
maybe you've got oil dripping on the pipes you cant quite see?

 

The smoke is coming from the underside of the #1 pipe. The only thing under it is the heat shield that protects the oil cooler housing, but the smoke is definitely above the heat shield, so that rules out the oil cooler. Nothing else is close enough to the exhaust to get vaporized, so I think that the exhaust is shooting out from the bottom side of the manifold flange. The smoke also increases with engine revs, suggesting it's not just something vaporizing.

The spec is 15 ft-lb according to Clarks. I might try going 20% over...

 

Could the gasket be busted prematurely?

 

Certainly possible, but unlikely since I installed the headers to the head on a bench, not groping around in the engine bay. But I don't have a replacement gasket and it is non-trivial to get the headers off with the engine still together. I need a quick fix to make it to 944Fest this weekend. With gasket sealer I could just loosen the headers to make a gap to apply the sealant, if there is a sealant out there that can handle the temps in that location.

 

To make sure it's a gasket failure or cracked manifold, and not oil leaking down from a cam shaft leak (common), pull the fan fuses and start the motor. Hold a piece of tissue around the suspect area and if it's really an exhaust leak, you'll see the tissue flutter. If it doesn't then you've got an oil leak onto the manifold.

 

After a much closer look, it appears that I have oil seeping from the bottom-front cam tower bolt. I don't know why the smoke appeared to increase with revs, but it is definitely a leak issue. It seems odd that oil would find a way out from there, though, since there is a lot of gasket between that bolt and the oil gallery of the valves. Maybe it is leaking from the back of the cam gear housing and pooling at the bolt before continuing to fall down to the manifold?

 

There's a cork gasket that is a common, cheap to fix failure item. The front cam tower leaks are common issues as well due to the age of the rubber seals in these old cars. Unfortunately, this repair is a lot more involved. There's a real good link for the cam tower seals repairs: http://blog.dietersmotorsports.com/?page_id=113.

 

Yeah, I just replaced everything a few months ago when I did my head gasket. Used every single gasket in the Reinz gasket set. I pulled out that bolt and there was oil in the hole, so I think it may actually be the cam tower gasket itself. The motor was still pretty hot when I pulled it out, but it came out really easily, and when I checked the torque on another bolt, it was pretty low. I would have thought a hot motor would actually have higher torque values on the bolts, so I'm thinking that either things loosened up after I did the initial install or I used the wrong torque value. Later tonight or in the morning when the motor is cool I will torque all the cam tower bolts to 14 ft-lb and see where I am. If I'm still leaking, I'll put some gasket sealer in that bolt hole to get me through the weekend.

 

Talking with another local 944 owner who did two cam cover gaskets in about the same time frame you describe, he discovered you have to re-torque the bolts after a few heat cycles as they work their way loose. After doing this on the second gasket it's been leak free for quite awhile now.

Maybe you'll get lucky and re-torquing the bolts will help. ??

 

Yep. That seemed to be it. No more leaks now. All of the bolts were several ft-lb low on torque. Heading to 944Fest this morning.

 

Have fun @ TheFest. It's a great time and meeting some of the yahoos on here makes it even better!