Two quick questions and then maybe a deeper dive to help me solve my problem.

2007 MCS has low oil pressure light on at idle. Goes out with RPMs. Changed oil to Liqui Moly 5w-40 and OEM filter after all the advice I read on here. Still low at idle. The filter was swapped during a valve job (more on that later). Wix Filter came out bent/melted?

Pic of WIX filter after 60 miles:

Paper isn't collapsed, hard plastic is bent/melted

First question!! What does this spring do and does it look right? Lots of conversation on the R53 side about Drain Back and Bypass, assuming this is Drain Back?? It's easy to depress, and assuming with the filter installed it's always depressed, so not thinking this is a low pressure solution. Pic of Spring:



A little more background before question #2...
Bought the car with 189K on it and I knew I'd need to do clutch and timing chain. On my drive from VA to AL, it blew an exhaust valve in #3... Towed it home, yanked the head, changed all the valves. That's when I put the WIX filter in. Also found pieces from a timing chain guide in the pickup screen, but apparently from a past timing chain because the one it had when I bought it was intact. After reading the forums and changing the oil/filter, I still had the light. Price of a sensor was cheaper than a gauge so I swapped the sending unit. Still had low light at idle at OT. So, bought the gauge - and subsequently the adapter for the head fitting...

At startup had 20 psi. After warm up had between 6-8 psi. Interesting fact; with 2k, 3k, 4k RPMS, only get about 12 psi max! So here's question #2!!

Question 2!! - Motor has no knocking really, definitely not rod knock. There's a sound, but not easily describable; it's not rhythmic. Not sure if the oil pump is trashed or Crank Bearings. So, pump would be an easy (not cheap) swap but wondering if I can disassemble it to look at the lobes for damage? Maybe junk in the bypass valve/spring?? Not sure how I could bench check that vs. replace. I just don't see how the bearings would have gone that bad after only about 300 miles of driving with no oil pressure issues before the valve job.

NOT afraid of doing a tear-down, I'm just looking for advice on whether the pump could be my simple solution or what to look for to confirm it's not the pump before I tear out the motor.

Thanks in advance!

 

Troubleshooting last night - found out that the spring holds oil when depressed (filter in), and drains with filter out. Y'all probably already knew that...

So not bypassing oil there. Probably pull my pan and take a look around the pump this weekend. Going to remove the sprocket and see if the gears grind or turn smooth before I spend any money. Maybe I can get a feeler into the rods/crank bearings? Anyone have specs on those?

 

Did you get your issue figured out?