exhaust leak sound goes away after a few minutes

i just drove my 77s and was driving in traffic today and saw the temp rise to 210...not to alarming as this has happened before. so it stayed there in stop and go traffic for about an hour or so.

i have never pushed the car and have never floored it in the past couple of years of ownership. it has the 11 blade fan and tensioners and no thermal reactors. it has 139 000 miles and has the history all the way back to 82. in other words, the previous owners really took care of this thing.

i got home and parked it for about 4 hours and started it up... i heard a dreaded exhaust type noise!!! well i shut it off and started it up again to listen to where it was coming from. it seemed to be coming from the left side of the engine...i could hear the brap brap brap from the top and bottom...funny thing is that it went away after about 5 minutes....i just parked the thing and am afraid to drive it...NEED HELP>>and opiniions...thanks...you guys are always the best

A broken head stud comes to mind since it happened to me on my 74 2.7.

Joe

A broken, or pulled, head stud is possible. when exhaust leaks are young, they go away after warmup. Eventually they stop going away.

I think you can take the valve covers off and inspect the ends of the studs to see if they are still snug. Exhaust leaks are not going to hurt much of anything, they hust sound lousy. A pulled head stud demands attention before any further driving.

------------------
'83 SC

an update.

the sound has not returned...seems like the exhaust is louder when cold...but not as loud as the first time....it starts up and runs fine with a very quiet possible sound....if if goes away after being on for about 3 minutes, can i eliminate the head stud problem from my concern list?/? thanks

Unless you have done a compression test with the engine cold, I don't think you can eliminate the stud problem from your worries. If it is a broken or pulled stud, the leak you hear is combustion products leaking between the cylinder and head junction! Bruce Anderson's 'Porsche 911 Performance Handbook' (available at most major chain book stores) has some deamatic photos of damage done by flame cutting with broken studs ... if allowed to continue while driving a 'spitting' or 'cylinder-slapping' engine, both cylinder and head can be damaged beyond repair!

------------------
Warren Hall
1973 911S Targa

how much of a difference in psi between cylinders would indicate at least a slight problem?

Well, let's say 5 of 6 are within 5 psi of 150 psi ... if the suspect cylinder was 130 psi or less, that would indicate a problem.

------------------
Warren Hall
1973 911S Targa

hi,

results of the compression are in...

driver's side, font to rear:

155
135
127

passenger side, front to rear:

155
155
157

is this indicative of a snapped or pulled stud...how many miles will this last? it doesnt make any noise as it did before...

Looks like a pulled or stud in the process of pulling out on the No. 1 cylinder over on the side next to No. 2. I can't really tell you how much time you have left ... kind of depends on your local climatic conditions, and length of your trips. If possible, I would avoid any use at all when the temps are above 85 F. And, no trips over 30 minutes, either!

------------------
Warren Hall
1973 911S Targa

a mechanic checked and advised that torquing down was in order...this was done and no more noise.haha.