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Ask Gm Tech (Cam) Your Own Question
Gm Tech (Cam)
Gm Tech (Cam), GMC Mechanic
Category: GMC
Satisfied Customers: 29520
Experience:  GM Grand Master Technician 2007. 14 year experience.
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GM envoy: I have a 2004 Gmc envoy that has a exhaust smell

Customer Question

I have a 2004 Gmc envoy that has a exhaust smell coming in thru the heat and ac ductwork . with the blower off we do not smell anything but as soon as you turn the blower on you get the smell any ideas?
Submitted: 5 years ago.
Category: GMC
Expert:  Gm Tech (Cam) replied 5 years ago.

GM Tech (Cam) :

Hello, I'm Cam. Please include all the details about your issue so I can accurately advise you. I cannot see your vehicle so please be detailed.

GM Tech (Cam) :

Does it smell if you use the blower with the key off?

GM Tech (Cam) :

sorry engine off and key on?

Customer :

no there i dont notice any smell then if you turn the blower off and open the windows let it air out close the windows it seems fine but as soon as you turn the haet or a/c on you can smellit

GM Tech (Cam) :

So physically running the engine is what is makes it smell.

Customer :

seems to be it appears to get stronger as you come to a stop

GM Tech (Cam) :

Ok so have you checked for the exhaust manifold leaking?

Customer :

yes we put it on a lift and could not find any leakage at the manifold or at the pipe flange

GM Tech (Cam) :

Did you remove the shield over the exhaust manifold to look? the cranks can be under there.

Customer :

no I have not removed the shield is this a common problem on this motor

GM Tech (Cam) :

yes, on this it is,

GM Tech (Cam) :

But also the oil cap being loose had been the cause of some .

Customer :

how is the smell getting into the system is there a intake around the cowl area

GM Tech (Cam) :

The inlet is above the cowl under the right wiper.

Customer :

I am going to meet my wife for lunch shortly I will check the oil cap and get back to you after

GM Tech (Cam) :

Bookmark this page so you can easily navigate back to it, and so you know, you can reply at any time for follow up information regarding this issue, even after you accept my answer and I will reply. Please don't forget to click accept at some time as that is my only means of compensation for assisting you.

Customer :

went and checked the oil cap it looks ok was tight oring looks good