2008 Yukon Denali Exhaust Manifold Heat Shield Breaking Off...

[KATfishing]

2008 Yukon Denali 6.2 L AWD - The bolt heads on the rear two exhaust manifold bolts are broken off (one on each side). My local shop is going to install rear corner brackets (again, one on each side) to seal the leak. Other bolt heads are ok for now but I just noticed a rattling noise and suspected the heat shield on passenger side manifold... sure enough, bolts are still in manifold, but heat shield has broken away from manifold where the bolts hold the heat shield onto the manifold (quarter sized holes in heat shield). Quick back story: This vehicle replaced a 2005 Chevy Trailblazer LS where the bolts broke off in the head when replacing the manifold and the shop's attempts to extract them didn't work without having the head removed and a machine shop extracting the bolts... way more than I wanted to spend (thousands), so I traded the vehicle in with disclosed issue and purchased the Denali which I've had for a year. Anything related to manifold bolts scares me, so here are my questions... Are the bolts that hold the heat shield to the manifold easy to get out, even if those bolt heads break off when trying to remove them? Manifold itself seems to be in good shape. I'm trying to avoid risk of needing to go down the same path as the Trailblazer, which is why I'm requesting the brackets to be installed versus updating the bolts that hold the manifold to the head all the way around. How big of a job is it to remove the heat shield bolts from the exhaust manifold to replace the heat shield? Any and all perspectives welcome. Fingers crossed for some reassurance. My shop will do the work, but I wanted to get some opinions here before I call them on Monday.

 

[STORMIN08]

The heat shield studs are usually the end of the manifold bolt...all one piece.

I would warm the engine, upon cool down...try to loosen all bolts.

If they dont, 90 degree die grinder with a wheel and cut the head off.

Then just dona header and new bolts.

 

[KATfishing]

The heat shield studs are usually the end of the manifold bolt...all one piece.

I would warm the engine, upon cool down...try to loosen all bolts.

If they dont, 90 degree die grinder with a wheel and cut the head off.

Then just dona header and new bolts.

OK - just to clarify... Do the bolts that hold on the heat shield go all the way through the manifold into the cylinder head? If so, are they essentially the same as the other bolts that hold the manifold to the head? I'm just fearing the stud being broken off in the cylinder head and worried that the bolts needed to hold on the heat shield will break off and be stuck in the cylinder head. OR, do the bolts on the heat shield NOT go all the way through and are just mounted to the manifold itself. Sorry, I only work on brakes so I'm just trying to learn enough to have some basis when I call the shop. I'm concerned that now since I need a new heat shield that this could quickly snowball into the same situation as my Trailblazer, where bolts were breaking off in the head, shop couldn't get them extracted without removing the cylinder head... resulting in a very large bill. Thanks!

 

[STORMIN08]

Honestly, i would have to look and i am away from my vehilce till next weekend.

I was thinking the heat shield was a small stud that is an extension to the manifold bolt.

The heat shield stud will break long before the manifold bolt.

 

[sk1dm4rk]

On my Esky, the bolts holding the heatshield to the manifold were not the same ones that attach the manifold to the head (read: not studs).

When my shields rotted off, I left them off and had no issues (they were both off for almost a full year). Recently, I replaced that cancerous situation with stainless headers.

Regards,

Mark

 

[KATfishing]

On my Esky, the bolts holding the heatshield to the manifold were not the same ones that attach the manifold to the head (read: not studs).

When my shields rotted off, I left them off and had no issues (they were both off for almost a full year). Recently, I replaced that cancerous situation with stainless headers.

Regards,

Mark

Hi Mark - Thanks for your post. That's what I assumed after looking at the bolts connecting the manifold to the head and I can see these are different. I'm thinking they don't even going into the manifold... just bolt to it. I was thinking about removing the heat shield and just leaving it off. The part is about $50 through GM parts direct. I asked my shop for a quote to get part through them and install it. We'll see how important I think it is when I see their quote. That will probably be the clincher!