My 2009 Mini Cooper S 130,000 miles is having low oil pressure light coming on at idle. From what I have found it's OK at start-up, but after driving for 5-10 minutes and coming to a stop (low idle), the oil pressure light will come on.

What I have done. Bought the car used with failed timing chain. Removed cylinder head and had valves replaced, replaced timing chain components. Drove for about 150 miles before the low oil pressure light first came on. Removed oil pressure sensor and installed manual gauge. Road tested and found oil pressure to be around 40 psi at cold start-up, but then after taking for 5-10 minute test drive and letting engine idle oil pressure dropped off to 5 psi. Decided to replace oil pump, oil filter, and fresh 5-30 full synthetic oil. Road tested and same thing after 5-10 minute drive low oil pressure light came back on at idle. I did not verify with manual gauge this time as I'm sure I will get the same results showing 5 psi or less.

My thoughts: Is there anything that I could have missed when reinstalling the cylinder head? I'm not sure how the valve lash adjusters get their oil pressure. Or something with the variable valve timing? Of course rod/main bearings could be a cause.

 

Were any plastic pieces from the timing chain slide rail, timing chain tensioner guide, or timing chain guide broken off but never found?

 

Failed timing chain would lead me to believe the oil pump now has issues. It could have sucked up timing chain guide pieces. Did you pull the oil pan when replacing timing chain?

 

I did pull the oil pan and removed plastic pieces from the broken timing chain guide. Also pulled down windage tray for further inspection. Oil pump has now also been replaced.