I just got done installing a built LS3 in my car, Ive had no luck thats for sure. I got everything in and done. Went to go start the car and after about 5 min I turned the car off to check over things. Started the car back up and no oil pressure!!! It also is making a LOUD squealing noise so I shut it off QUICK. Drain pan...no metal...checked oil pump pick-up tube...everything looked fine. Did my oil pump lock up? I dont know if it would make a noise if it did. Or could my pickup tube be too close to bottom of the pan? I used a ARP washer on the windage tray to clear ARP rod bolts.

 

Verify with a mechanic gauge. Oil pumps, esp. new ones rarely just "go bad"

Where is the squealing noise coming from? remove the the belt, see if it goes away. Need to isolate the noise.

 

replaced the oil pump, pick up tube and windage tray....all good now!