White Smoke Coming From Exhaust Pipe

Subject: Re: Billowing White Smoke Coming From Exhaust Pipe

1969 Chevy Camaro, V8, 307, Rochester 2-bbl carburetor, automatic, 114K miles – Lots of white smoke coming out the tail pipe when the engine is idling and also while driving. I have also seen a small puddle of oil sludge lying on the garage floor under the tail pipe. But what concerns me the most is the billowing white smoke at idle and driving. I also could not keep the car running.

The 307-engine would rev up and then rev down and no matter what adjustments I made to the carburetor screws controlling the air/fuel mixture the engine would still die. So I removed both heads and found that one of the heads seemed to be warped and one of the cylinders had a little bit of water on top of one of the pistons.

Is this where the white smoke was coming from? Some how this car must have overheated and I was not aware of it when it happened. The light on the dash may not have been working or the gage wire to the block was not plugged in maybe. I replaced the original valve stem seals with new umbrella shaped valve stem seals.

What kind of checking do I need to do for the piston rings? What about checking the clearances before I have all the head work done? I want to try to keep the original engine since this is a classic car. This engine was rebuilt at one time but I can’t be really sure what the mechanic did?

I’m convinced though that he did the bare minimum of work to rebuild it. What is the work I need to do to get the car in good reliable running order? Thanks, Mary

Hi Mary,

The white smoke out the tailpipe was coming from coolant/water dripping inside one of the cylinders which probably got there via a tear in the head gasket or the warped head you found. You probably don’t have anything wrong with the pistons themselves since the engine was at least running and you did not mention anything about an engine miss or other indication of a lack of compression issue.

Since you have already removed the heads, you can’t really do much testing on the compression of the bottom half of the engine either, so I would go a head and proceed with doing a complete valve job and have the heads resurfaced and checked for cracks at a machine shop.

You should also install a new thermostat and would be a great idea to have the radiator rodded out or replaced to make sure there is not restriction in the bottom of the radiator.

You don’t want to overheat the engine and have to do this again, so take precaution now to prevent it from happening in the future. The problem you have now is the symptom of another problem, so you need to correct the initial overheating issue or this will happen again.

Austin Davis

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