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.

 

low oil pressure solution when hot and at idle mini couper r56 s

GOOD DAY I AM THE OWNER OF A 2007 MINI COUPER S R56 AND LIKE MANY OTHERS I HAD THIS PROBLEM WITH MY CAR WITH LACK OF OIL PRESSURE AFTER THE ENGINE WAS WARMED UP
I am an amateur mechanic and like many others I tried to find a solution to the problem on the internet but to my surprise I did not find anything that would solve the problem, only theories
Then I decided to buy another engine with the same problem to study it to understand the functioning of the oil path in this type of engine
I will try to explain briefly how this problem can be solved
First of all, the functioning of the lubrication system must be understood, after which it is very easy to diagnose
1. The oil pump only makes volume, it does not make pressure
2 The pressure results from the opposition to the resistance between the engine elements, respectively the distance between the components of the oil path, that is, the lighter the engine, the more the friction resistance decreases due to the size of the space between the components and this leads to a decrease in pressure oil
So the tolerance between the elements that are in motion, i.e. the crankshaft bearings and the camshafts, must be checked
What I found in my search on the internet is that most of them have repaired the bottom, i.e. the crankshaft in the engine block, and have not solved the problem because they have done half the work and the defect is in the top, i.e. the camshafts, because they are the first to wear out (in the absence of a correct or timely oil overhaul) being moving components and the furthest from the lubrication source in the oil path
This engine is known that if (the overhauls are not done on time or the wrong viscosity oil is used or the timing plastics break and clog the oil pump suction) the oil does not reach the camshafts in the time required during cold starts and causes ease in the bearings and over time the distance between the bearings increases and this leads to loss of oil pressure when hot
Now I'm only talking about the scenario where you have low pressure with a warm engine because there may be other problems, not just the ease of the cams and I'll explain
The lack of oil pressure when hot is due to the fact that when cold the oil is thick and then the engine eases, meaning increasing the distance between the components does not affect the oil pressure because cold oil, meaning thick, means increased friction resistance with engine components
But the problem occurs when the oil heats up and becomes thinner, meaning easier friction with engine components and then the oil pressure drops when hot
Now that I've explained the reason, I'll detail some checks that should be done

MEASURING OIL PRESSURE WITH A MECHANICAL TESTER AFTER THE OIL HAS EXCEEDED 90 DEGREES CELSIUS

1 Check and clean the solenoids from the variable distribution from the intake and exhaust because if in the past you had dirt or filings you will find the screens clogged
2 Open the oil pan and make sure that the screen the oil pump is clean (if it is a solenoid pump, unscrew the solenoid as it also has a sieve)
3. open the cover of the camshafts and measure the ease of the bearings with (KOLBENSCHMIDT 120000417001) plastic gauge
procedure:
Start measuring each bearing separately starting from the one furthest from the oil source, that is (EXT camshaft IN camshaft) the first bearing next to the gearbox and the last one next to the distribution
You will notice more ease on the one next to the gearbox because it is furthest from the oil source
unscrew the first bearing, measure it with a plastic gauge, tighten it (with TORQUE) back in place, then unscrew the next one, not all at once
If you have an ease greater than 0.050, that is, on the measuring table, meaning greater than the third position from high to low, then you have ease on the bearing and it requires replacement or repair, otherwise you cannot restore the pressure of oil
THIS CHECK IS DONE TO AVOID SPENDING MONEY FOR NO REASON

I repeat myself again there can be several causes but it depends on the situation I explained the lack of oil pressure when hot when the oil has thinned
the defect being at the top i.e. at the end of the oil path the engine will not have knocks and will even be quieter this will lead you into errors of that kind you must use the mechanical pressure test and wait for the oil temperature to exceed 90 degrees Celsius otherwise you will diagnose incorrectly
If you have a noisy engine also check the oil filter housing and the crankshaft bearings because in this case you have problems on the bottom i.e. in the engine block

There would be a lot more to explain but as I said for a correct diagnosis you must understand the lubrication system of the car

for those who are capable the repair is cheap and can be done without disassembling the engine for those who are not
have a specialist repair the camshafts

I want to I would like to point out that I used google translate to translate the text and I apologize for any ambiguities in the text
I posted with the idea of ​​helping other people who have this problem
I will leave an email in the description for those who want more details (rambamihai@gmail.com)
I wish you a good day