Exhaust manifold bolts

[Big_kid]

I have a couple broken exhaust manifold bolts. One on each side. The bolt head is 13mm on all of them. I see at the salvage yard about 95% are 10mm bolt heads. Do you think mine have been changed at some point or is it what ever GM used at the time. Thanks…

[shakenfake]

Could have been changed. I suggest you purchase ARP bolts when you go to replace them.

[2018GMC]

Here is a how to video. He mentions that the replacement bolts are different size than stock.

 

[shakenfake]

I need to buy an acetylene torch...

[richard wysong]

at least its not a Ford

[Supreme Pizza]

I had to pull the head on my 5.3 recently, and I found that the very 1st and very last exhaust manifold bolts were both broken by a previous owner. To my surprise, all the other bolts came out with no problems at all. I drilled out the center of the broken bolts, and they came right out using a square easy out. I followed the OEM directions on re-installation, and everything has been good to go. As far as the size goes, I would just use what ever you have on hand, or buy some on Amazon. If you are torquing them correctly, I don't see why the bolt head size would matter at all. The instructions call for threadlocker/locktite and a specific torque spec, possibly with a 1st and 2nd pass if memory serves.