Rough idle

[1990whitez]

My sister bought a 99 alero a few months back, the car has run well for her until now, when starting the car the idle is very rough and white smoke is coming from the exhaust, smells as if it were coolant or antifreeze, the idle settles but the smoke is still present anyone know anything about this, it is a 2.4 liter 4 cyl

[vamc]

That would be an EGR valve. That white smoke that you are seeing is due to the engine is burning lean, that means that the engine is not getting enough gas. If you see black smoke, that means the engine is getting to much fuel. You will need a new EGR valve. It should be by the throutal(sp)body.

[1990whitez]

will the egr from a 99 grand am or a cavalier 2.4 work in the alero?

[biv343]

Last I knew (unless something changed) is that the Quad 4 engines don't have EGR valves....

[JTrujillo86]

The egr system is built into the engine. There is not a valve that needs to be replaced.

Jeremy

[vamc]

No i disagree, it is not built in the engine. it sits on the throutal body. if it was built in the engine, then you can not replace it, and the engine would be no good! think about it. Trust me, its where i told you it would be!

[biv343]

And I will disagree with you. I have a 99 Alero with a 2.4L engine. There is no EGR valve built into the throttle body. There's a MAF sensor, throttle position, etc built into the throttle body, but unless someone popped my hood and stole my EGR valve, your information is incorrect.

Quad 4 engines have never had EGR valves - they were able to meet emissions requirements without them. Go to any auto parts website or open any auto parts catalog and look for an EGR valve for a quad 4. I'll bet you'll see "not applicable".

Since the original post mentioned "white smoke" that "smells like coolant", I would probably suspect a head gasket issue. Engines that run lean usually don't produce white smoke, at least if they are tuned up correctly. Generally the only things that can cause an engine to run excessively lean are faulty coolant temp sensors or MAF sensors.

[biv343]

After doing some checking, apparently there are EGR valves on the 2.4L motors - some parts suppliers list them, others do not. I will stand corrected. The 2.3L motors did not have EGR valves - I assumed that was the same in the 2.4L motors. Going rate seems to be in the neighborhood of $175-$200. Not something I'd try replacing unless I was damn sure it was the problem.

Regardless, I still don't think that an EGR would cause rough idle and white smoke.

[vamc]

the egr valve controols how i agree w/ what you said about the head gasket, but if its not the head gasket, its the egr.

[jamcllw]

Sound like a head gasket to me
and if memory serves me correctly the 2.3L quad 4s had headgasket issues.

[vamc]

its the 2.4 and the 3.4 have the issues. head gasked issues. its from the dex-cool.

[jamcllw]

I've never heaerd of the 3.4L having head gasket issues. Maybe the 3.4L DOHC engines but not the one's that come in Aleros

[vamc]

I strongly disagree, all the aleros have this prob with malabos and inpalas. even ask ANY GM DEALERSHIP!

[BNaylor]

Originally Posted by vamc

I strongly disagree, all the aleros have this prob with malabos and inpalas. even ask ANY GM DEALERSHIP!

Before the bumper to bumper ran out on my '02 Alero GL2 3.4L V6,
the local GM dealer changed all possible defective gaskets per GM Technical Service Bulletins (TSBs). They changed the intake manifold gaskets. No mention was ever made about defective head gaskets nor is there a TSB out on that issue.

It is not to say that you may never have a head gasket issue arise but it is not a common failure item on the Alero, GrandAm and other GM models with the 3400.

I've never had any issues with running Dex-Cool either. I own 3 GM "W" bodies and one "N" body ranging from 1997 to 2002 model years.

[vamc]

Every dealership and every ase, i have spoken to, have said this is a common prob.now, im not saying there was a recall or anything, but ask people that have 50,000 mi on there car and they/ most anyways; they will tell you that they had to replace the gaskets. Like anything else, dont fix it if its not broke.