2015 Sierra 6.2L Exhaust Manifold Bolts

heierlu · June 2, 2021

I just noticed that multiple exhaust manifold bolts on both sides are broken. Does anyone know the factory part number for these bolts or perhaps the specs on them? Looking to get some ARP bolts to hopefully prevent this in the future.

Also - for anyone that has had this happen, did you replace your manifolds as well? I've got 110k on mine and they look kinda rusty. Not sure if it's best to just replace them while I'm in there. OEMs look to be under $100 each side.

CamGTP · June 2, 2021

It's been a common thing since the LS engine started in the trucks back in 1999. I see it all the time still.

Just about any parts store sells new bolt kits and I haven't had any problems using them. It would takes years to see if the issue would happen again with new bolts. I never replaced the manifolds, just cleaned them up, inspected the MLS exhaust gasket and put them back on.

Check GM parts direct online to see if there is an OEM number you can find. Otherwise you could buy the ARP stuff if want those.

Nitrousbird · June 3, 2021

There is a company on eBay that sell stainless exhaust bolts (alloyboltz). I bought a set of header studs for my LS7 and the quality is actually really good while being FAR cheaper than the ARP bolts. I would recommend going that route. Once my truck is out of warranty - and assuming I keep it - I will be doing this upgrade on it.

heierlu · June 3, 2021

I checked GMParts Direct as I've ordered a bunch of stuff from them in the past, but can't find the bolts anywhere on there. I reached out to ARP and they said they need specs of the bolts since they don't have anything listed for this exact application. Hence why I made this post Was hoping someone had the GM part number handy or the length and thread pitch of the bolts.

I'm hesitant to buy anything off of eBay these days. You just don't know where the stuff is coming from and the quality of it.

Edited June 3, 2021 by heierlu

CamGTP · June 3, 2021

This is what you need, the bolts have all be the same thread since the LS engines. Some just had different socket heads throughout the years.

https://hinsonmotorsports.com/products/hinson-arp-ls-exhaust-manifold-header-bolts-set-of-12

heierlu · June 4, 2021

4 hours ago, CamGTP said:

This is what you need, the bolts have all be the same thread since the LS engines. Some just had different socket heads throughout the years.

https://hinsonmotorsports.com/products/hinson-arp-ls-exhaust-manifold-header-bolts-set-of-12

Exactly what I was looking for. Thank you very much!