Burning smell after replacing exhaust manifold

[wallyuwl]

I just replaced the exhaust manifold on my 2010 Chevy Equinox, 2.4L. The old one was cracked. Now I'm getting a burning smell coming from the back of the engine.

Parts I replaced besides the exhaust manifold:
- O2 sensor replaced
- cleaned throttle body
- replaced a metal ring gasket between the manifold and catalytic converter.

Would any of these things cause the smell?

I also bought, but forgot to replace, the exhaust manifold gasket between it and the engine. You can't see it which is why I forgot about it, and the part was in a box. I didn't realize it until I was about 5 minutes done with the job. Doh!

Any thoughts? Is this something that is likely to resolve itself (new O2 sensor burning in, etc.)? Should I just check to make sure all the bolts are tight on the manifold (that would only take about a half hour).

If I had to do the whole job again it would probably be about 2 hours now that I know what I'm doing and things won't be quite as tight as they were from the factory.

 

[hansj3]

Burning cosmoline from the o2s or manifold. If it keeps up check again in a few

 

[gathermewool]

You re-used the old manifold gasket?

What kind of burning smell? Oil, wire insulation, rubber, exhaust?

 

[wallyuwl]

Originally Posted By: gathermewool
You re-used the old manifold gasket?

What kind of burning smell? Oil, wire insulation, rubber, exhaust?


Yes, I reused it by mistake. You can't see it so it didn't register to replace it while I was doing the repair. I even bought a new one. It is a metal gasket so less of an issue than if it were a plastic one.

Burning smell is hard to describe. It is coming from the back of the engine, but you don't smell it much from the bottom of the engine. Would make sense to be just something burning off. Sounds like it might take care of itself. I guess if it continues after a week or so I'll have to redo the job and replace the gasket.

Oh, I also sprayed almost all the bolts connecting the manifold to the engine, and the manifold to the cat, with BP Blaster to get them off and I'm sure some of it got on the engine. Maybe that is burning off?

 

[Ga129]

Originally Posted By: wallyuwl
Originally Posted By: gathermewool
You re-used the old manifold gasket?

What kind of burning smell? Oil, wire insulation, rubber, exhaust?


Yes, I reused it by mistake. You can't see it so it didn't register to replace it while I was doing the repair. I even bought a new one. It is a metal gasket so less of an issue than if it were a plastic one.

Burning smell is hard to describe. It is coming from the back of the engine, but you don't smell it much from the bottom of the engine. Would make sense to be just something burning off. Sounds like it might take care of itself. I guess if it continues after a week or so I'll have to redo the job and replace the gasket.

Oh, I also sprayed almost all the bolts connecting the manifold to the engine, and the manifold to the cat, with BP Blaster to get them off and I'm sure some of it got on the engine. Maybe that is burning off?


Some parts like exhaust manifolds can be coated with something to prevent rust and extend shelf life. It's probably something of the like burning off. It could also be the PB blaster. Just keep an eye out for smoke and if the smell continues after a couple days recheck all the new wires and make sure nothing is burnt. I had some headers that were painted going on a car but the paint actually burned off when in use it was just there to prevent rust while sitting in a warehouse.

 

[CT8]

Take it apart and put the new gasket back in a poorly done job is not worth doing at all.

 

[JamesBond]

New exhaust parts always smell "hot" for a number of miles/drive cycles. Its probably the manifold, it will go away.

 

[gathermewool]

I've heard of a few people who re-use exhaust gaskets without issue, but I don't believe they're designed to be re-used. I've re-used muffler gaskets without any issues, but I'm not sure I'd trust re-using a manifold gasket.

I know you're probably tired of the project, so maybe wait a week or so and then install the new gasket.

I agree, that the spray is most likely that of the penetrant over-spray and header conformal coating.

 

[The_Eric]

Verify there is nothing touching the exhaust that shouldn't and then drive it. It will go away.

As for the gasket- if it was a multi-layer steel/ss piece, then it will likely be just fine.

 

[TFB1]

Originally Posted By: The_Eric
Verify there is nothing touching the exhaust that shouldn't and then drive it. It will go away.

As for the gasket- if it was a multi-layer steel/ss piece, then it will likely be just fine.

Agreed, no chance I'd pull it apart again unless it was leaking...

 

[wallyuwl]

Originally Posted By: TFB1
Originally Posted By: The_Eric
Verify there is nothing touching the exhaust that shouldn't and then drive it. It will go away.

As for the gasket- if it was a multi-layer steel/ss piece, then it will likely be just fine.

Agreed, no chance I'd pull it apart again unless it was leaking...


Drove it for about twenty minutes today, the smell is greatly reduced. Just coating of some sort burning off probably, as some have suggested.

Everything seems fine. Since it is a metal gasket, I don't plan on tearing it all apart again unless something goes wrong. If it was a plastic or rubber gasket I would replace it.

 

[The_Eric]

If it were a rubber or plastic gasket, it'd be toast in minutes.