hot spot on 4.3L Caprice engine

[Todd1963]

Hi folks

I recently bought a '95 Caprice Classic with 64k on it and really like the car, despite having put on a new alternator and A/C compressor this summer.

I'm having trouble with an engine hot spot where the emissions control
stuff comes off the battery-side manifold. The hose gets very hot when the car is idling or at slow speeds and a rubber/hot electrics smell comes though the air vents, especially with just the vent on and not the A/C.

I had the car checked by my local mechanic and he could not find anything specific wrong (the engine runs well and cool otherwise), but this problem came out of nowhere just last week, so something has changed.

Any advice/ideas you folks might have would be most appreciated



Todd 1963

[Blue Bowtie]

Welcome Aboard!

I'm not certain what "emission control stuff" yuo may be asking about, so I'll have to just guess.

If you are experiencing heating of the rubber hoses and pipe for the A.I.R. system, the check valve is likely failing. That can allow very hot exhaust gasses to flow back through the plumbing, heating the steel tubes and rubber hose, and eventually creating damaging condensation in the air injection pump.



G.M. published a TB regarding this problem in 1994 for all the LT1 and L99 engines.

You can remove the check valve and easily test it for leakage.

[Todd1963]

Blue Bowtie:

Thanks for the insight on the possible check valve problem.

It's ironic you mention that, because I had asked my mechanic if just replacing the rubber hose and that disc-shaped valve would be a start
in getting the thing fixed and he told me "that's just a check valve"
and it would be "fixing the effect, not the cause."

Thanks again. I owe you one.


Todd