Smoke

[marcus mcgee]

> (snip)
> pulling a hill (PA
> or WV type), the GMC will have a small puff of black smoke from the
> exhaust pipe and then you can see either white or grey smoke under
> the motorhome coming somewhere from the area of the engine
> compartment (maybe 1/4 of the way back from the front.).
>(snip)
> Sometimes it will occur when the transmission downshifts -- but not
> always.
> Any hints as to the next place(s) for us to check?

The smoke may not be coming from the same place. The black smoke from
the tail pipe sounds like an over rich kickin of the carb secondaries.
Not serious and can be adjusted at the carb.

The grey smoke coming from under the coach may be actually coming from
ATF fluid overflow splashing on a hot surface and burning off. Very
serious porblem in that it could cause a fire. This may be from an
overfilled trany or the trans may be overheating. Either way it should
be taken care of. This is my best guess, others here may be better
informed.

By the way, was it you or your mechanic that decided to change the
exhaust system? If it was your mechanic, find a new one ASAP. An
exhaust system does not make smoke except when something drips on it or
the engine puts it into the exhaust.

Good luck finding the problem.

Marcus

 

[les & des]

> Do you have an auxiliary transmission cooler? This would be like a small
> radiator in front of your main radiator positioned down low. If not, you
> certainly should have one to keep the trans from overheating

Thanks! After all of the hints about the smoke being tied in with
the Transmission, we are going to change our cooler, and have the
Transmission serviced, even though it has not been but a couple of
years since it was serviced.

We were reading in GMC Marketplace about the need to reroute the
Transmission Cooler lines from going under the exhaust manifold as
they are now. Does anyone have any knowledge on this?

We keep a plugging!
'73 Painted Desert
Les & Des
Living Praise Ministries

mailto:lesndes
Visit us at: http://www.livingpraise.org

 

[les & des]

>
> By the way, was it you or your mechanic that decided to change the
> exhaust system? If it was your mechanic, find a new one ASAP. An
> exhaust system does not make smoke except when something drips on it or
> the engine puts it into the exhaust.
>

Marcus,

Thanks so much for you help. As you will read from one of our other
post, we are going to replace the Transmission cooler first, and have
it serviced. The exhaust system needed to be replaced. Several
holes, etc. It wasn't something that someone sold us. We just have
to keep doing a little at a time. Because we are from NC we do not
see smoke on a usually basic. We don't travel in the western part
of the state much. In the past year, we have made several trips to
PA, and that is where we have seen the smoke. Usually only once
on a trip but the last trip it happened two or three times. Compared
to the flat lands of NC, there are some good size hill in PA.

We really appreciate all of your help.

'73 Painted Desert
Les & Des
Living Praise Ministries

mailto:lesndes
Visit us at: http://www.livingpraise.org