GMC5.3

Will my car smoke due to shot or misplaced exhaust manifolds? Looks like smoke in my engine bay is coming from both manifolds on both sides

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Injuneer

Did you work on the engine recently, and spill oil on the manifolds? Or is this just something that suddenly happened one day, out of the blue? Is it possible the valve cover gaskets are leaking?

What do you mean by "misplaced"? Installed incorrectly?

And these are totally stock LT1 exhaust manifolds?

Powersource

Also, if the gaskets are graphite/paper, they'll smoke if they're leaking because well, paper burns/smolders.

What does the smoke smell like??

GMC5.3

Ive been working on the engine for what seems like the past year, total newb that changed both headgaskets, i guess it could be possible the valve covers are leaking but i specifically saw when the car warmed up a bit after idling for 5 mins smoke coming from the heat shield on the driver side manifold, passenger side exhaust seems to be the culprit too. And yes totally stock

I remember having a hell of a time with the stock exhaust manifold gaskets(steel metal paperish gasket) so i figure maybe i messed something up. I dont remember spilling oil anywhere, and the smoke just smells like burning smoke, will video help?

GMC5.3

So i pulled my driver side manifold gasket, could the black around the exhaust ports be my smoking problem? Thank you

Injuneer

No, the black is just the normal carbon from the exhaust, collecting on a piece of the gasket that is blocking the exhaust port. But that's not going to cause any smoke.

It's remotely possible the manifolds are cracked, but it would be odd for both sides to be cracked. I've never seen one actually crack, but they are just cast iron. And an exhaust leak will usually produce a distinct "tick" sound.

GMC5.3

Ok so i may of found the culprit, now i understand from shboxs website that my car has 2 cats, in the diagram is #32 and #1 the cats. If so my car only has #32 and i believe the smoking is coming from the collector #32 and #33. Looks like there is a paper gasket there that is really old. Could that be my problem and maybe its just going to both sides.

I took the car around the block and noticed still some white smoke as i accelerated, could this be old coolant still in my exhaust from before i changed my headgaskets. Car was barely at 160 degreees. Thanks for all your help

Injuneer

A leaking gasket at the triangular flange would not cause smoke on both sides of the engine. Additionally, exhaust it generally invisible, unless the air is very cold.

If you do not have the passenger side cat (#1), what do you have in it's place?

Since you don't indicate your location, its hard to guess what the ambient temperature might be, but if the air is cold, it's very normal to see white vapor (not smoke) coming from the exhaust, until the exhaust fully warms up. When you burn gasoline, you make a lot of water. That leaves the engine as a vapor, and when it hits the cold exhaust it condenses and becomes visible.

I think you need to have someone with a reasonable amount of mechanical experience take a look at the problem.

GMC5.3

just to give you guys a little video of what im dealing with, i changed the flange gaskets today on both sides and while running the smoke looks to be coming from the passenger side cat at the top. I cant see if there are any cracks in it but this is whats holding me back.

The video starts off on the driver side cat and goes to the passenger side,
video-2012-01-28-14-30-30.mp4 video by jperraul - Photobucket