Need info on two valves....

Coalbunny · February 24, 2013

I'm looking for detailed info on the PCV valve and EGR valve. 2001 GMC Sierra Z71 SLE 4x4 short-bed with 5.3 liter engine.

What do they do?

How do they work?

What are they made of?

Stuff like that and whatever else you can tell me.

Coalbunny · February 25, 2013

Ok. I live in an area where there are no emissions tests. Can my truck run without the EGR valve, and if so, is it better or worse?

Daryl Z71 · February 24, 2013

EGR stands for Exhaust Gas Recirculation valve, and it has to do with emmisions. Someone else is sure to know more about it in detail. I've only ever replaced one pcv valve, and that was in my Grand Prix. Can't remember what it does though.

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MikeNH · February 25, 2013

You can't just remove it not to mention there would be zero gain for removing either one- they don't cost you power or anything.

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8.1HD/ALLISON · February 24, 2013

As stated EGR is Exhaust Gas Recirculation valve. It reroutes a certain amount of exhaust gas back through the intake manifold to be reburned for emissions reduction. PCV is Positive Crankcase Ventilation valve. It is a one way check valve that allows crankcase vapors to be drawn into the intake manifold and burned, thus reducing pressure in the crankcase caused by blow-by. The EGR valve is electronicly controlled by ECM(engine control module). It is made from metal. Usually mounts to one exhaust manifold and then has a metal pipe routing engine exhaust back to the intake manifold. The pcv valve is just a check valve, no computers controlling it. Can be plastic or thin metal. It mounts in one of the valve covers usually with a hose running back to the intake manifold.

Daryl Z71 · February 25, 2013

You can remove it. You'll have to tune it out of the computer, and block off the openings for it once removed. Here's a link to another forum where they are discussing this http://www.performancetrucks.net/forums/gm-engine-exhaust-performance-21/egr-removal-145431/

Coalbunny · October 2, 2014

Since I posted this thread I found that one of my neighbors is an old school mechanic. He showed me how to resolve the EGR valve issue without replacing it. My mileage increased a lot, since then.

Sure has me kicking myself in the backside after the GM dealer told me once that I had to replace it. Why replace it when I can clean it myself? Bingo. Just saved myself $650.