6.0L oil pressure issue

[jott5555]

While driving down the road i got a P0521 Code and noticed the oil pressure gauge showed low (about 18PSI). I reset the code and installed a new pressure sending unit and screen just to be safe. I no longer have the code however my oil pressure is not the same as before the code. Currently I have 38ish PSI at start up and around 18 at idle when warm. Before this code it ran around 40 at idle. At the same time as sending unit i put in new Mobile1 5-20 Synthetic and a Mobile1 Filter. After the oil change i have noticed some slight lifter tick when cold in the morning.

 

How do I check the oil pressure with a mechanical gauge to verify i have low oil pressure and it is not the gauge. If it is low Oil pressure at the sending unit should i replace the pump and screen next? Is this a common issue? It seems i read more and more about spun cam bearings.

 

Truck info

 

07 Chevy Avalanche

6.0 w/ 84K

 

Thank you

[jott5555]

I had a mechanic hook up a pressure gauge I had 80KPS at idle, 170KPA @ 2k & 220 KPA @ 3k. Are these numbers normal?

[txab]

Isn't that like 11, 25, 31 psi? If so it's low

[jott5555]

Correct its low... much lower then the 40 at idle I used to Have. I'm going to try a fluis this weekend if that dosnt work then I will replace the oil pump