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superwofy superwofy is offline
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Red face Low oil pressure at idle advice - 12-02-2018, 03:43 PM

Hello N54 tech!
This is my first post after years of lurking .

I'm going to be rebuilding the front end on my car in my driveway soon. CHRAs, wastegates, m3 control arms, steering rack, servotronic an oil pan gasket and some other small stuff.

Ahead of this, I thought it'd be a good idea to check the overall health of the engine with an oil pressure test. I've attached the results and the gist of it is that, at idle, the pressure is very low. Under any sort of revving, it picks up quick and is more than adequate (per BMW's figures). Needle on the gauge fluctuates slightly.

Oil is Petronas syntium 7000 0W40 changed 5000 km (3100 mi) ago. Injectors are brand new index 12 so I doubt the oil is diluted.

I think that the pressure is way too low at factory idle speed so I used MHD to increase to 900 and it looks good but I'm still worried.

Should I consider inspecting and replacing the rod bearings while I'm in the pan? What about the mains? I will be checking the pickup tube.

Thank you.

Attached Images
File Type: pdf Oil pressure.pdf (184.5 KB, 26 views)

Last edited by superwofy; 12-02-2018 at 08:34 PM..
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superwofy superwofy is offline
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Default 12-30-2018, 03:47 PM

bump?
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arkie6 arkie6 is offline
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Default 12-30-2018, 09:26 PM

Get an oil analysis performed to see what wear metals are present and amounts. This will also tell you if your oil is still in the proper viscosity range. It could be breaking down and performing like a thinner oil.

How accurate is your oil pressure gauge? Has it been calibrated? Have you compared it to another gauge?
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Dave @ BMS/Fuel-It! Dave @ BMS/Fuel-It! is offline
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Default 01-02-2019, 01:24 AM

Quote:
Originally Posted by superwofy
Hello N54 tech!
This is my first post after years of lurking .

I'm going to be rebuilding the front end on my car in my driveway soon. CHRAs, wastegates, m3 control arms, steering rack, servotronic an oil pan gasket and some other small stuff.

Ahead of this, I thought it'd be a good idea to check the overall health of the engine with an oil pressure test. I've attached the results and the gist of it is that, at idle, the pressure is very low. Under any sort of revving, it picks up quick and is more than adequate (per BMW's figures). Needle on the gauge fluctuates slightly.

Oil is Petronas syntium 7000 0W40 changed 5000 km (3100 mi) ago. Injectors are brand new index 12 so I doubt the oil is diluted.

I think that the pressure is way too low at factory idle speed so I used MHD to increase to 900 and it looks good but I'm still worried.

Should I consider inspecting and replacing the rod bearings while I'm in the pan? What about the mains? I will be checking the pickup tube.

Thank you.

How many miles on the engine ?



http://www.fuel-it.biz/

e92 AT 335xi 2.0
Doc Race Kit 6062
Fuel-It!Platinum DIY PI Kit + Stage 2BL
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superwofy superwofy is offline
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Default 03-16-2019, 08:09 AM

Hey,

Mileage is 118k mi.
After an oil change with the same oil it behaves the exact same so oil dilution can be excluded.

It behaves very similar to this video:
BMW N54 engine oil pressure at idle, warm. - YouTube

That is, with factory idle rpm. Perhaps less fluctuation on the needle but I use a different gauge so who knows? Very slight rattling can be heard on a cold morning which goes away quickly (1-2 min).

When doing the oil pan gasket I checked the strainer and it was perfectly clean. No signs of metal either.

I'll be dropping the subframe again and I honestly don't know if I should just tear into it and plastigage + replace w/ standard bearings. All on a driveway w/ axle stands .
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