Exhaust leak?

k9handler · 07-24-2002, 03:53 PM

Ok, on my road trip my car developed an exhaust leak...and my question is once I take delivery of the car in Germany, what/where should I look for the leak? It sounds like it is coming from the drivers side section. Could it be one of the air valves for the emissions? Just want to get this repaird/replaced as soon as possible and any advanced planning I can do will make me feel better since I hate just not knowing. Maybe it's just the perfect time to go with a performance exhaust system.

Jim Sims · 07-24-2002, 03:59 PM

Check for broken or pulled headstuds

Jim

Noel · 07-24-2002, 04:01 PM

H.D.

Use a three foot piece of garden hose and hold one end to your ear, then listen for the leak while the car is idling. It is best to do this when the car is cold as it gets quite hot under the car.

Good luck,

Noel

k9handler · 07-24-2002, 04:08 PM

Pulled head studs

I sure hope not!!! That would really suck, engine was rebuilt just over a year ago and only has about 5000 miles on it. Would a pulled or broken head stud cause a loss of power and other symptoms as well? Thanks for the info Jim, and I will look at that area.

Noel...the hose tip seems like a great idea, will make sure to use that trick.

Early_S_Man · 07-24-2002, 04:20 PM

HD,

Are you saying it lost power at the same time that an audible exhaust leak became noticeable?

Jim Sims · 07-24-2002, 04:31 PM

During the rebuild were timecerts or some other type of thread insert installed in the case? Was the case checked and remachined as required? Were the heads flycut and the cylinders trimmed as required? If these measures weren't done as required, then the studs could pull or the head/cylinder assemblies could loosen. Cheers, Jim

dd74 · 07-24-2002, 04:41 PM

Backfiring? A persistant hiss? What?

k9handler · 07-24-2002, 07:17 PM

No Jim, no loss of power at all. The leak is very slight and can only be heard at idle and low rpms...like at take off. Once going down the road it can't be heard at all. The work on the engine was done just prior to me getting the car, timecerts were installed and new raceware studs as well...other than that I am not sure of the degree of the repairs. The engine is very clean and strong, nothing would have lead me to think this would happen. To describe the leak would be a steady hiss and pinging sound, but once going down the road it's just too quiet to hear cause of the engine noise I guess. I have heard the same sound once before, and this was on a 930 at a local autocross. I was told that the 930 had blown out one of the air valves in the emmissions system...this is why I mentioned it above.
Any further assistance will be greatly appreciated.

Jim Sims · 07-24-2002, 07:34 PM

Sounds more like a vacuum (air leak). Use the hose or get a mechanic's stethoscope (safer and more efficient IMO) and probe around listening for the leak. There's a lot of things that can leak air on a CIS system. Jim

Noel · 07-25-2002, 03:09 AM

HD,

Are you getting the tell-tale sound of exhaust popping on deceleration? Usually this will indicate an exhaust leak if you are running slightly rich. I too orginally thought I had an exhaust leak, but now I'm leaning toward a possible CIS adjustment. My cars exibits the exhaust popping noises over 4000 rpms while decelerating. I'm scheduled to take the car in on Tues. So I'll let you know what happens.

Noel

k9handler · 07-25-2002, 06:33 AM

Jim and Noel...thank you.
I am not able to look at the issue until my car is in Germany (late Aug)...but the two of you have pointed out some good issues that I will look at. The more I think about it, a CIS leak would make sense. Noel - no popping on decel out of the norm, there has always been a real light popping and it is consistant/same as before.