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2001 LeSabre: Exhaust leak


DrRadar
01-11-2016, 02:35 PM
My son's 2001 LeSabre (3800 N/A) was smoking under the hood and the odor was entering the cabin. I decided it was likely due to coolant and oil leaks from the valve covers and manifold gaskets as well as a crack in the upper radiator hose. So I replaced all the gaskets and hoses and cleaned it up some.

After a test drive, smoke still coming from under hood. It appeared to come from the exhaust crossover joints (mainly front) and possibly from the seam on the crossover "shroud". I suspected some rust damage to the crossover, so pulled it out. (And spent my Sunday digging out a broken bolt. :banghead:)

I don't see any visible rust on the crossover (but can't inspect the entire thing visually). Could it be a clogged catalytic converter causing back pressure and the leak? Or is it more likely something under the hood like a head gasket. (I hope not. :uhoh:) Any suggestions on isolating it?

polarzak
01-11-2016, 03:29 PM
You need to clarify "smoke". Is it smoke from oil/coolant leaking and dripping on a hot exhaust pipe, or "smoke" from exhaust gas? Does the "smoke" smell like something burning or what comes out your tail pipe?

DrRadar
01-11-2016, 03:58 PM
Smells like exhaust to me. But keeping an open mind on the source.

polarzak
01-12-2016, 07:18 AM
Well, you can do several things. Park the car and see if there are any drips after parking over night. If you park outside, stick a piece of cardboard underneath the engine. If none then you probably can eliminate an oil or coolant leak. Even if the leak occurs only under the pressure of a running engine, you will still have a drip. Drips are hard to find because the actual drip point may be nowhere near the actual leak. It you are able to degrease the underside, and then follow the leak back, you should be able to find the source. One youtube video guy coated the bottom of his engine with baby power, and found an oil leak that way. A dirty, messy job, but apparently effective.

If you have an exhaust leak, you may actually see it with the car running on a cold day if you look down through the engine or up from underneath. You should be able to see it much like one can see their breath on a cold day. I see you are in Texas, so this might not be an option if it is not cold enough.

Alternatively take it to a garage and have them put it on a hoist.

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