soon as i saw the video i knew it was the pcv valve, my gtp did the same thing when i put my junkyard motor in it

 

I was gonna say after seeing that last video, PCV valve for sure. LOL. Good find! Glad it wasn't the bearings! O'reilly's should have those for a couple bucks.

 

GM PCV Valve Part Number: 25179136

I'm working on diagnosing the PCV system right now. Taking off the oil cap or popping the PCV valve out of the block while the engine is running relieves a strong vacuum inside the block. I understand that the PCV valve is supposed to vent excess positive pressure from the block back into the intake, but if it's pulling a vacuum at this location, I'm not convinced that the PCV valve itself is bad. Any idea why such a strong vacuum is being generated?

 

Whoa, that's a new one on me. Let me know what you find out.

 

If you remove the oil cap, put your hand over it, then rev the engine, does the vacuum get stronger or weaker? If it gets stronger, pull the valve covers and look for an intake valve that isn't opening. Just a theory.

 

So....now I feel like an idiot.

I had my right valve cover venting to my intake manifold instead of my throttle body. Although they're only about 2" apart, the manifold vacuum port pulls very hard vacuum and the throttle body port is nearly atmospheric. With the setup I had, my intake manifold was sucking a large volume of air out from my valve cover and was dumping it back into the intake manifold.

Looks like my problem is now solved and hopefully this thread will help others down the road. You've gotta be careful with those vacuum lines, folks!

Big shout out to hrcslam for his help in diagnosing this, I owe you a beer next time I'm in Arizona!

 

I'm glad that was an easy fix. It's also nice to know your engine pulls that much vacuum too. No worries about brakes huh? LOL. Good find and thanks for posting up the solution.