Pesky exhaust manifold studs

[Kunz, Bob]

This job is done and Tony's advice was spot on. I used two cycles of propane torch and freeze-it spray (liquid R134a). I had one more stud break off on cyl #1 inside the casting, so all four studs on cyl #1 and 2 were weak/broken. I did use a 5/32 socket as a drill guide in the head to get my drill centered on the remainder of the stud. Not a lot of torque needed on the broken off ones, I think all the resistance to removal is on the interface of the shoulder of the stud to the head so once that's gone, bolt comes out easily.

Now that the engine is quiet again, all the other creaks are evident on this 26 year old car. :(

--bob


From: Tony Hoffman [mailto:auditony at gmail.com]
Sent: Monday, January 09, 2012 6:21 AM
To: Kunz, Bob
Cc: quattro at audifans.com
Subject: Re: Pesky exhaust manifold studs

I always replace them all. Heat them with a propane torch first, cycling that with your favorite penetrant or water (yes, it does work). Do a couple of heat cycles, then work them back and forth slowly and they should come out. I've rarely broken one off using this technique, probably have pulled hundreds.

Tony
On Sat, Jan 7, 2012 at 3:59 PM, Kunz, Bob <bob.kunz at hp.com<mailto:bob.kunz at hp.com>> wrote:
Hello all!

It was time to fix the exhaust manifold gasket leak on cylinders 1 and 2 and of course each had one of the studs broken off inside the block. I've gotten one out; will begin working on the other but now a new question.

Should I take out the existing "good" studs and replace them? The risk I see is they will break off as I remove them causing me more work vs. leaving as is and having them break off in the next few years. Any opinions on which way to go? Parts not an issue since I have all new studs, washers and copper nuts.

Particulars... This is an '86 5Ks Avant (KZ engine), yes it's a FWD. Has 175K miles.

Thanks!