'01 Blazer ZR2 noise after lower intake seal replacement.

I recently replaced the lower intake and valve cover seals on my '01. I followed the how-to guide posted by "drdd" to the letter. The kit also came with upper intake seals, and I replaced those as well. Everything went as planned, and I allowed just over 17 hours for the RTV silicone to cure before starting. Now I am noticing a buzzing noise while sitting in the driver seat. The noise can only be heard from inside the truck, and only occurs between idle and 1000rpm. The sound appears to be coming from under the dash. The speed of the sound increases with rpms. I am not sure what it is, and it is very hard to describe. I turned off the radio to be sure it wasn't electrical interfearance from the coil or alternator. It almost sounds like a low pressure sucking noise, or an electrical popping noise. The engine runs very smooth, and oil pressure, electrical, and water temp are all within norms. I am positive that that sound was not there before replacing the seals. Any ideas or suggestions are welcome.

At last! I found the noise. I bought a diagnostic stethescope and found the noise to be coming from my driver side PCV valve. I replaced it, and the noise continued. I took the new PCV valve out and shook it and replaced it. The noise stopped. My question now is: I noticed that the PCV valve was connected to the intake and there is a substantial vacuum to the valve. Is this normal to have vacuum hooked to it? Or did I cross connect a hose while reassembling the parts after the seal replacement? Hmmm.

Yes it should have engine vacuum on it.
And always use a Ac delco PCV valve.

Hey, thanks for your reply. That noise has benn Bugging the hell outta me for a couple of weeks (not to mention a noise like that can be worrysome if it wasn't there before a big job). I just can't believe that I could hear that thing in the passenger compartment (louder than someone might think). I replaced it with whatever the computer at Autozone recommended. don't think it was an AC Delco, but it seems to be doing the job. One more question though. The old one still looks good and rattles like it should and sounds just like the new one when I shake them. Could I have fudged anything on the valve cover that would make a rattle like that. I replaced the gaskets and the bolt plugs, then torqued them to 120 in/lbs. The noise is gone for now, but if it returns, I'm afraid there may be something wrong. Ideas?

If it returns get a ac delco pcv valve first.

5 days later and the noise has yet to return. thanks for the advice. will definately keep it in mind.