Exhaust Leak!

[wilpetty]

Need help with exhaust leak...There is smoke in the engine bay area after motor gets running for a little while...Also a tick noise that sounds like an exhaust leak...How do I go about locating the leak? Fumes are coming through the vents so I dont like to drive the blazer for an extended amount of time...Should I take off exhaust manifolds and reinstall them? Need some advice...

 

[454Sub]

Short of a cracked manifold, it can only leak in a few spots. At the heads, which is the manifold gaskets, the manifold to the Y pipe. and where the Y pipe joins the single exhaust. Most likely its either the manifold to head gaskets, or the manifold to Y pipe gaskets. I would bet manifold to head gaskets personally. Cheap and easy fix, just takes a little bit of time and frustration.

 

[496truck]

Don't rule out cracked manifolds. Very common. I though mine was cracked, it came off in 2 pieces. If you need to replace them they are fairly cheap but your options are limited to made in china or made in china. I got mine from 1AAuto.com good price and came complete with hardware and gaskets even though the listing didn't say so.

 

[wilpetty]

So my best bet is to take off manifolds and redo it...I guess I will get new gaskets, but I believe they may have been put on backwards...If the manifolds are not cracked and are reusable, could I sand them a little and paint them?

 

[496truck]

They tend to crack under the heat shield where you can't see them so inspect carefully.

They can be painted but I suggest oven paint or cooking grill paint over the "high temp" header/manifold paint. I have heard it holds up better even on red hot turbo housings.

 

[wilpetty]

Very good info to know!!!
Grill Paint

I think this will do after a little sanding. And for the price it is definitely worth to do to make it look better under the hood (my manifolds look all rusted)...

 

[wilpetty]

Bored as heck so I took a pic of the rattle can for anyone interested in wanting to do something similar in the future and didn't notice the link above. For 3-4$ It will def make my manifolds look much better.
Monday is when I will remove manifolds and see how it all plays out...Main goal is to locate and fix exhaust leak!

 

[496truck]

Cleaning and prep will be KEY to making that paint last.

 

[Deuling]

I put that on my headers and by the time I wrestled the headers in half the paint had scratched off. I used a whole can on two shortys and hit them with a torch to bake the paint on.... I sandblasted and put em on bare. I'd rather have uniform rusty headers than partially rusted lol.


But I'm sure on a rough casting like manifolds have, it will stick better.

 

[ryoken]

if your gonna do new manifolds, ask for Dorman...

 

[Blue85]

Well you have to find the leak before buying parts. Chances are you can feel the pulsing hot air with your hand or you can use a piece of tubing as a stethoscope. On a cold start you can probably see where the fumes are coming from. The #1 place for leaks with stock exhaust is the rear of the manifolds. The frequency of the ticking can give you some idea if you're hearing a single cylinder pulse (manifold to head leak) or a 4-cylinder leak (donut gasket or something).

 

[wilpetty]

Great info to know...I hope I can locate the leak monday. Will keep you guys posted...

 

[wasted wages]

also if you have AIR Injection ( smog manifolds ) there will some small tubes that thread into the exhaust manifolds..... they rust out like crazy and leak also.....