I'm sorry my first post here has to be because I'm stumped and needing help, but I'm so glad I found these forums.

I have an '02 2wd 2Dr Blazer LS w/ auto tranny, and for the last couple of months I've had this loud buzzing/grinding almost like a bearing noise coming from the backside of the engine behind the throttle body intake and in front of the distributor. To pinpoint it, it sounds like it's coming from about where the fuel lines come into the upper intake.

I heard the noise right after I bought the vehicle 2 years ago, but it went away never to make a noise again until this winter, a good 50,000 miles later. The truck now has 105k miles on it.

It started out just on cold mornings, and it would go away after a few minutes when the engine warmed up. Later it started happening when pulling off from a stoplight, etc, and would seem to go away after getting up to speed. Now it's getting so bad sometimes it's doing it while idling. That's how I was able to locate where the noise is coming from. When I revved it up to about 2000-2500rpms and held the rpms steady the noise would cut in and out. I've searched all over the forums, and nothing I've found seems to sound like my problem.

Also another problem I found today is I've got oil coming from the pvc valve through the hose into the intake, and now the piece of plastic on the intake has a film of oil on the inside. With the plastic off the throttle body I opened the throttle up full throttle, looked down inside, and it looks black down in there. Is there supposed to be oil coming through this hose (normal) or has the pvc valve gone bad?

The truck is currently out of commission for the weekend while I'm having a new jug put on the radiator, but it won't be ready 'til Monday, so I'm hoping to get everything fixed while it's already down since I drive 70+ miles a day in it for work.

Any help or suggestions would be appreciated.

 

Remove the PCV valve and shake it. If it does not rattle, replace it. Heck, if you don't know the last time it was changed, just do it anyway. You might also clean the throttle body. See if the noise continues.

 

Check the distributor for the source of the noise. Carefully place a couple fingers on your distributor cap and see if a vibration there matches the noise you hear while the engine is running. I also had a sound at the back of the engine bay. I traced it to the distributor. When I pulled it out I could spin the gear by hand and hear a squeak and could tell it was near the top of the shaft. I loaded a syringe with oil and worked some into the small space between the top of the distributor and outer shaft cover. I assume that the bearing at the top of the shaft needed lubricated. I priced a rebuilt unit for about $90 so if I have more noise from this one I'll do the replacement.

 

I'm getting same noise from my '93 for a while now. The shaft of my distributor has about 1/8 in. play up and down, also back and forth. Now it won't idle right or stay running, and it's running backwards right as it dies, pushing fuel back up. Think maybe it's got out of time somehow? Should I go ahead and replace the distributor? Or might it be my timing chain slipped?

 

My `94 had the same noise at about 200k. I pulled the distributor and found it to be very rough, almost as if it had a bent shaft. I went to Auto-Zone and got a replacement with a life-time warranty for about $100. That was two years ago, I just heard that noise again, pulled the distributor, same thing. This time when I went to Auto-Zone, I got a replacement for $0! Runs like brand new once more!