Oil Temp Running High - The Unofficial BMW M5 Messageboard (m5board.com)

Craig T · 3rd July 2009, 21:15

Hi
My engine oil temp is running too high.
I had to replace the Oil Level Sensor at the end of Feb during an Oil Service because the sensor was shot. After a week or 2 car threw it SES because it was running to cold. So, I replaced the Thermostat.

Since replacing the thermostat the Engine Coolant Temp has been fine, remaining at the 12 o'clock position when cruising but the oil temp varies from 100degC to approx 115degC. When the oil temp gets above 105/110degC I then receive a warning that to "check engine oil level" - of course when I check the oil level is fine.

Due to the car running to cold for a prolonged period of time, looking back it had probably been running too cold for a couple of months. I decided to replace the oil 4 weeks ago (approx 2000miles). But the engine oil is still too hot.

From what I recall, the Oil Temp used to run at about 85-90degC.

Any ideas what could be causing this?
Blockage to the Oil Cooler?
Stuck Valve within the Cooler?
Bad sensor?

cheers
Craig

PS: Please note that I did use the search facility first, but could see any posts that seemed similar.

DouglasABaker · 3rd July 2009, 22:00

You replaced the oil level sensor / thermostat and now your car is running too hot. Replace your oil level sensor again, since it is also the temperature sensor. I suspect you got a bad one.

the thermostat is unlikely to be involved. It could make your water run a bit warmer, but not much (a few C).

IF it is NOT the sensor / temperature sender, then you probably don't want to think about the alternative, as it will involve replacing some combination of radiator, water pump, and oil intercooler. Which one would be difficult to diagnose.

d-

Cemessi · 3rd July 2009, 22:15

I've had 3 M5's. All have run at the 80-85C position when driving normally. The highest I've had any of them is 125 on a track.

nightkrawler · 5th July 2009, 17:36

you have another bad oil level/temp sesnor. the level part of the sensor works on heating/cooling of the sensor. the dme heats the sensor to a temp higher than the surrounding oil, then measures the time it takes for it to cool back down. if there is not enough oil in the crankcase it wont cool correctly and hence you get the check oil level message. i doubt you have a blockage in the oil system as then you'd have a host of other problems. these cars dont really have an oil "cooler" in the conventional terms. its an oil to coolant heat exchanger under the intake.

E55AMG2 · 6th July 2009, 23:26

Quote:

Originally Posted by nightkrawler

you have another bad oil level/temp sesnor. the level part of the sensor works on heating/cooling of the sensor. the dme heats the sensor to a temp higher than the surrounding oil, then measures the time it takes for it to cool back down. if there is not enough oil in the crankcase it wont cool correctly and hence you get the check oil level message. i doubt you have a blockage in the oil system as then you'd have a host of other problems. these cars dont really have an oil "cooler" in the conventional terms. its an oil to coolant heat exchanger under the intake.

+1, I had the same thing happen.

Craig T · 11th July 2009, 19:57

Thanks Guys,
My first thought was just a faulty sensor, but wanted to bounce it off those more experienced.
I'll order myself a replacement.

cheers
Craig

noxcape · 14th July 2009, 15:13

Make sure the coolant level (when cold) is at the mark. If it is 2-3 cm lower than normal you can have the oil temp higher. That happend to me. Now the coolant is at correct level and .... smiles ... everything goes right!

Craig T · 24th July 2009, 18:24

Thanks noxcape,
Checked the coolant level a couple of days ago, it's fine, dead on the cold mark.
cheers
Craig