Tahoe Exhaust Manifold Bolt R & R

2500hdee · July 28, 2010

'02 Tahoe LT, 5.3L, 4WD, G80, etc. w/180K

Have been having severely hot days lately. The forward-most exhaust manifold bolt head on the d side popped off leaving the shank even with the top of the flange and it's a pretty persistent leak so needs to be repaired. Did a bunch of research and see this is a common occurrence. Soaked each bolt with PB Blaster after trying to loosen a couple and hearing them start to squeal. That was Sunday and believe me, they took an inordinate amount of arm before they started to give. Went back out tonight and they turned very easily; thanks Mr. PB. Ordered a stud & nut kit from the local auto parts guy and will do the R&R Sat morning. I'm just documenting this because so many have had more break when they started this and this may offer a better alternative to the left handed drill bit, helicoil, EZ out, MIG gun hassles. I absolutely hate drilling out broken fasteners BTW.

The bolts were supposedly upgraded on 02 and up model years but many seem to have issues on the newer ones as well

My '01 2500HD w/215K on the clock has one with the top broken off as well but it has just a slight exhaust leak so no rush on it

jblakeney · July 28, 2010

Both of my GMT-800's have the bolt directly under the alternator pad broke off on the exhaust manifold.... Nothing like a broke bolt. 99 1500 5.3 and a 01 2500 6.0.... Neither are leaking....

I am gonna leave the 2 monkeys broke off until the engine has to come out of either.....

Jbo

2500hdee · July 31, 2010

Just finished the R&R. For some reason, the parts stores show a 10 mil stud as the replacement. Unfortunately, the bolts are M8/1.25 so I had to search and search until I found a match at NAPA 600-2604 for the stud and nut kit, perfectly matches up. I also got the gasket set there....... NAPA/Fel-Pro MS 92467

jblakeney,

That's exactly where mine broke off, thankfully, there was enough of the shank left to muscle it out with arc-joint pliers. My 6.0 also has one broken off bolt head but it didn't leave much left to work with (very slight exhaust leak when cold). Will probably mig a nut onto what's sticking out of the head and go from there. I'm sure you guys know this but anti-seize is your friend when working with exhaust bolts

jblakeney · July 31, 2010

Yes the bolts are 8x1.25 (I don't have my pocket scale so I don't know how long)..... GM 12560206 is the number I bought to replace mine on my 99...... I bought them in 2001 so the number probably has changed..... They are still in my console... HAHA

Jbo

scott 730 · August 1, 2010

Are you guys checking your manifolds for warpage when you have them off??? I have the rear 2 drivers side bolts broke off flush with the head. Put a straight edge on the manifold after removing it and saw alot of warpage on mine. The center port area needed quite a bit of material removed to true it up. Decided to go the cheap route and put the resurfaced manifold back on with new GM bolts and Fel Pro gaskets and it works just fine so far, even with 2 bolts missing.

desrtrat · August 2, 2010

thats why when i did my header install everything with threads got anti seize compounded including spark plugs when they were reinstalled.. i hate stuck bolts..

jblakeney · August 2, 2010

Spark plugs SHOULD ALWAYS have there threads coated with ANTI SEIZE. Period END OF STORY...... Any person that does not coat them should be shot on the spot..... Just as, spark plug wires, both boots should be field with dielectric grease, BOTH BOOTS....

Sorry Rant OFF

Jbo

jblakeney · August 3, 2010

Are you guys checking your manifolds for warpage when you have them off??? I have the rear 2 drivers side bolts broke off flush with the head. Put a straight edge on the manifold after removing it and saw alot of warpage on mine. The center port area needed quite a bit of material removed to true it up. Decided to go the cheap route and put the resurfaced manifold back on with new GM bolts and Fel Pro gaskets and it works just fine so far, even with 2 bolts missing.

Yes, I dooooo and either way it gets some passes on this machine... Which to the experienced or un-experienced person can be a deadly machine. I have launched a aluminum 4 cylinder head once.. Some moron turned the adjuster while I was in the middle of a pass..... Then I felt stupid.

Jbo