Would anyone know the exhaust manifold bolt torque specs?
2007 H3 I5
Had an exhaust leak and found the center bolt head was broken off, after a day of wrenching drilling and retapping, I want to be sure they are torqued to the proper foot pounds.

Thanks

 

It is 15lbs for all three passes when you tighten them down in a criss cross pattern

 

Thanks for the quick reply,

Any reason for the heads to be breaking off this is the second time this has had to be repaired, The dealer did it whan I got it at 30,000 mi. and now at 56,000. I do not think it was one of the previous ones and they put all new bolts in last time, ( because they left the old ones in the wiper recess area)
It was the center one, The head shears off the bolt and there is about 3/8" of the bolt sticking out of the block. Total PITA to do.

 

Exhaust Manifold Bolt Torque:
First Pass 20 N.m 15 lb ft
Second Pass 20 N.m 15 lb ft
Final Pass 20 N.m 15 lb ft

Add thread lock GM P/N 89021297 (Canadian P/N 10953488) to the exhaust manifold bolt threads.



tight mani.jpg (88.88 KiB) Viewed 45 times

 

probably a heavy handed mechanic. they often think they know more than the mfgr.
tire shops are notorious for this, take your own torq wrench!!

 

So when you put the bolt in, the head sheared off as you were tightening down, if that is what I read correctly from what you wrote, it sounds like to me that the bolts are too long, or something is stuck in the hole or the bolt is too big by a hair and causing the issue too. I would definitely use thread locker on it also as someone else mentioned. 15lbs is really nothing for a torque wrench either, if you have or know someone who has an inch pound torque wrench I would use that instead because it is less error for being off spec for torque, just my opinion a foot lb. torque wrench will do just fine also.

 

The head was snapped off the bolt when I was investigating a exhaust leak sound,
That is what I found after removing the manifold heat shield.
When I bought it in May I took it back for the same exhaust leak sound and the dealer had it for two days to get two of the broken bolts out.
They put in all new bolts and now it happened again.
When dissassembling the manifold bolts they sure seemed that they were torqued up pretty good even for having thread locker on them.

 

wow that is very interesting, because I have done head gasket jobs before and never had the bolts break off, sounds like a flaw from gm
good luck

 

If they get over torqued the manifold heats up, expands and pops them off. Could be that they were already stressed from being too tight before.
Torque sequence...

 

Thanks for all the info,
I will torque it up tonight and will be keeping an eye on them.
Has anyone else had this problem?