So my oil pressure takes 3 to 5 seconds to build up on cold start, verified with mechanical gauge. After searching I've tried different filters and 5w30 and 10w30 oil. Same results. During that 3 to 5 seconds engine fairly loud, but quiets down after oil pressure is built up.

Now I am wondering if used wrong oring. When I rebuilt the engine I used the red oring with a 00 lq4 pickup tube. Could my problem be the oring is the wrong one ?

 

What oil pump did you use?

 

Ported stock pump, new.

 

Choosing the correct o-ring depends on the design of the end on the pickup tube. If you went by this chart (even using a non melling o-ring) you should be correct. The red OEM o-ring is for the grooved or tapered pickup.

 

good to know. I think its a straight end ..... whatever was stock in a 00 silverado lq4. I will pull it this weekend and double check, but I don't believe its tapered. I know its not grooved anyways.

Anyone have part number for the black oring? Felpro maybe, would like to grab the orings from parts store before I tear into it.

 

not sure on Felpro part number but GM part is 12557752 (blue o-ring)

 

IIRC my 2005 LQ9 used the grooved pickup. It's hard to tell in the photo but I did use the Melling green o-ring, so my pickup was definitely not the straight pickup. I have 58lbs of pressure at idle.

 

Pulled the pickup today. Its straight and measures .87 the entire tube that goes into oil pump. Also attached pic of felpro red oring which advance says is correct.

So I need the black oring ?

 

With the straight pickup the chart says to use the OEM GM blue or the Melling black.
If the Felpro red is like the OEM GM red it is the wrong o-ring for the straight tube.

 

When you put the pickup into the pump there should be some resistance as the oring squeezes in. Is there?