EXHAUST PROBLEM / 3.1L V6 / CHEV LUMINA

[mossad]

I have a 1995 Chevy Lumina with the 3.1L V6.
Recently upon startup I hear something from the engine, and about the only way to describe the sound is a "putting" sound at idle. It's not the muffler, it is clearly from the engine compartment, and I "think" I can smell exhaust from this area, faintly. I'm not sure what this could be. Would it have anything to do with the manifold? Or any other ideas out there? Based on what I'm describing...is this a very costly repair? Also, am I hurting anything buy driving the vehicle in this condition? One final thing, after the car has been driven for a while, it does seem to be a bit less noticeable.

 

[Elroy the Unique]

Sounds like you have a cracked exhaust manifold

 

[mossad]

If my manifold is cracked...am I hurting anything by driving the car until I get it to the shop for repair?

 

[55Test]

Nah, unless you're sensitive to fumes.

 

[Elroy the Unique]

You should get it fixed. It can be dangerous to let carbon monoxide into your car, and it pollutes. Go to a junkyard and get a replacement.

 

[Oil stain]

Also, if it is a cracked manifold or a bad gasket, you will use more fuel because the o2 sensor will see more o2 in the exhaust which causes the car to run richer.

 

[mossad]

Thanks for the posts guys...Actually, I'm not one to neglect maintanence issues, and I'm calling my mechanic tomorrow to set up a time to get it fixed. The car has 130k on it now and it runs like new...looks brand new as well as it has always been garaged. I plan on driving it until the doors fall off anway, so it's best I get it fixed. I hope it's just a gasket. I can't wait to find out what the labor hours will be...

 

[alreadygone]

A manifold crack will often quieten after warmup because cast iron metal expands and crack "closes up". Bad gasket usually just keeps getting louder and louder.

 

[beanoil]

Had a similar issue recently with a Focus. The EGR tube was cracked. Good luck...

 

[mossad]

Ok, I have an appointment at the shop for 9/21.
My mechanic said that this particular engine does not have gaskets. The manifold is bolted right onto the valve cover. He also said it could just be the exaust arm that comes off the left side of the motor. Worst case, if it is the manifold, they take them off and have them machined so they can be reinstalled.

Whatever the problem is, it must be minor, because the noise stops just as soon as the heat gague begins to rise. The slightes warming of the egnine seems to mask the problem.

 

[turbochem]

quote:

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I have a 1995 Chevy Lumina with the 3.1L V6.

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Well, consider this coincidence:

I have a 1995 Chevy Lumina LS, 3.1L. It has 265000+ miles. It has a cracked rear manifold.....that (sort-of) seals after it is warmed-up.

Just a tip, the "seal up your cracked manifold" goop doesn't really work.....the fix can't be that cheep and easy.....

 

[mossad]

quote:

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Originally posted by turbochem:

quote:

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I have a 1995 Chevy Lumina with the 3.1L V6.

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Well, consider this coincidence:

I have a 1995 Chevy Lumina LS, 3.1L. It has 265000+ miles. It has a cracked rear manifold.....that (sort-of) seals after it is warmed-up.

Just a tip, the "seal up your cracked manifold" goop doesn't really work.....the fix can't be that cheep and easy.....

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Yeah, well I'll soon found out just how much it costs to repair.... It may just be the exhaust arm which extends off the side of the engine.. (fingers crossed)

 

[Quickbeam]

As Oil Stain pointed out any ambient O2 getting in upstream of the sensor will shift the loop lean and result in lower fuel economy. Best to get it resolved soon.

 

[DriveHard]

I had a 1994 Pontiac Grand Prix with the same problem...ended up being a loose spark plug.

 

[mossad]

What? HOw can a loose spark plug cause the issues I'm having?

 

[DriveHard]

It was just loose enough to allow a little bit of exhaust out on the power stroke (highest cylinder pressure). It was finger tight...I snugged it down and it went away.

 

[Market525]

Mossad, I hate to bring up a bad subject, but have you dealt with the intake gasket issue that so many of these 3.1/3.4/3.8L GM engines have? Or are you familiar with it? Sounds as if you really enjoy the car & plan to keep it. Just be warned that you need to attend to this issue ASAP.

 

[mossad]

quote:

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Originally posted by Market525:
Mossad, I hate to bring up a bad subject, but have you dealt with the intake gasket issue that so many of these 3.1/3.4/3.8L GM engines have? Or are you familiar with it? Sounds as if you really enjoy the car & plan to keep it. Just be warned that you need to attend to this issue ASAP.

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Yes, I have in fact. I purchased the car with 50k, and that was when I replaced the gaskets for the intake as they were beginning to leak. My mechanic said that when he replaced them, that GM came out with a better gasket to help solve the problem. So far, it is dry. I'm well aware of that issue with this particular egnine.

 

[mossad]

quote:

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Originally posted by Market525:
Mossad, I hate to bring up a bad subject, but have you dealt with the intake gasket issue that so many of these 3.1/3.4/3.8L GM engines have? Or are you familiar with it? Sounds as if you really enjoy the car & plan to keep it. Just be warned that you need to attend to this issue ASAP.

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Yes, I have in fact. I purchased the car with 50k, and that was when I replaced the gaskets for the intake as they were beginning to leak. My mechanic said that when he replaced them, that GM came out with a better gasket to help solve the problem. So far, it is dry. I'm well aware of that issue with this particular egnine.

 

[Market525]

Repaired at 50K, now at 130K? Don't know if you have ever had an oil analysis done, but might not be a bad idea to spend the $30-$40 at next oil change just to be sure there are no traces of coolant in the oil. I've just read too many horror stories on these GM intake gasket problems to gamble slowly destroying an engine with a very slow coolant leak.