When I did the tune up on my 05 4.3l I planned on replacing the PCV valve but couldn't find it
Maybe it truly is time for glasses but for the life of me I couldn't find it

 

Smack dab in the middle of the driver side rocker arm cover. Fits into a rubber grommet and sticks straight up with a 3/8" vacuum line on top of it. Gotta move some stuff out of the way to see it.

 

thats what I thought , but couldn't budge it in the grommet (square grommet?)

 

Yup, you know what they say about a square grommet in a round hole

 

Before you replace it, try cleaning it with brake cleaner. I have heard a lot of times that working.
If you do not have brake cleaner, it would most likely be cheaper to buy a new one than a can of brake cleaner LOL

and giggity Cap!

 

A lot of the aftermarket PCV valves are noisy, buzzing and such. Had that problem on one of mine. Drove me crazy trying to figure out what it was. Put in an AC Delco and the noise was gone.

 

Have to agree with the aftermarket sensors being noisy, took me awhile to figure out where it was coming from.

 

I have a friend with the 1996 Yukon (their Vortec V8 5.7L is a big brother to our 4.3L V6). His engine was buzzing at certain speeds and he couldn't find it. Finally with an auto stethoscope he located the buzzing. It was an aftermarket PCV valve with a split crimp! New AC Delco PCV and his engine is quiet again.