I did a seafoam treatment on my truck yesterday. I used the brake booster line and I guess I was too slow cause it starting smoking about halfway through pouring it in. After I shut it off for 10 minutes and started it is didn't smoke all that much. I'm gonna grab another can and do it again in a few days.

While it was bellowing smoke from the tailpipe I noticed some smoke right under where I was dumping into the vac line. i thought I spilled some and it was burning off the exhaust manifold but its actually the manifold leaking.

Is that something that needs immediate attention? I'm guessing its just a gasket between the manifold and the downpipe?

 

if you dont address it, you run the risk of burning your exhaust valve(s)

 

Why, because of it throwing off the A/F ratio and running too lean?

 

I thought it had something to do with backpressure...?

 

lol....i mean this in a nice way. not answering at all is always better than bad info

 

Ill keep that in mind..
But still, Thats what I thought my dad told me...
so yeah, my bad if im completely off on that..


EDIT !!! :
http://wiki.answers.com/Q/Will_an_ex..._to_the_engine

also:Any leaks BEFORE the cat and front Oxygen ( A/F Ratio ) sensor can cause a CEL as well as poor performance since the Oxygen sensor is the primary input for fuel trim ( lean or rich mixture ). Poor performance, acceleration, hesitation, fuel economy can all be affected by a leak before the front sensor.

 

So is there a gasket between the manifold and downpipe?

 

there are gaskets at every exhaust flange.
if the leak is not at the manifold / head, there is very little chance of burning valves.

an exhaust leak, even though you see exhaust coming out of the leak, will also draw air into the exhaust system after that exhaust pulse passes the leak, causing the O2 to register a lean mix and the ECU to inject extra fuel.

 

there are little doughnut gaskets between the manifold and the down pipe. there probably burned out on 90% of Toyota out there and people don't realize it. no risk of warping an exhaust valve that can only happen running an open manifold or no manifold where when you turn the motor off cold air rushes up and hits the hot valves.

 

I've gone through 5 pairs of those darns things in the last year....