4.6is Oil Temperature - too low or display not accurate?

[g300d]

I am monitoring oil temp at the cluster via test 16 recently and I am getting 75-85C oil temps after 30 mins of driving.

I am thinking it is a bit low, and starting troubleshooting.

Last night I started off with checking both ktemp and oeltemp at the cluster to see if they had the same value cold (vehicle not driven for a few days).

-Key position 1 ktemp at 30C but oeltemp was at -12C??

-key position 2 ktemp remains at 30C and oeltemp goes to 0C???

-Started the car and oeltemp remains at 0C and goes up from there to about 75-85C and ktemp was constant at 30C key off - on - start and started rising gradually to about 95C (Bremmen 95C Thermostat recently installed).

-now turned ignition off, ktemp remains at 95C, oeltemp goes from 85c to -48C(?????)

-key moved to position 2 immediately and ktemp remains at 95C, oeltemp goes from -48C back to 85C (lol)

So it seems to me like a sensor problem? Was just gonna shoot it with the parts cannon but I looked up the sensor and OE (which is what I am leaning towards for this application) is like $350. Not cheap and gave me pause and encouragement to look more into this lol.

Would love to hear everybody's thoughts and/or experience if any on this, have not found any matching discussions in my initial search.

[andrewwynn]

A few sensors go to very weird values with the engine not running. I have a handful of sensors i monitor and some go to nonsense

That said, most BMW motors have oil sensors with two outputs so it can be very very confusing to diagnose so I'm betting that's whats going on.

–awr–

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[g300d]

I believe you are on to something there Andrew. Came across similar talk on an E39 M5 discussion. The rev limit lights at least are supposedly an average of 3 sensor inputs. Seeing that I'll also be looking for references to that for the oil temp measuring system.

[g300d]

Andrew, you're right, below was posted in one of the threads I found. Supposed to be from WDS.

Poster said he found it at the E53 X5 4.6is section, but it mentions S62? But at this point I assume they are probably the same system considering the E53 and E39 are pretty much kissing cousins.

Oil temperature gauge

On the M-models, an oil temperature gauge is used in the instrument cluster instead of the fuel consumption indicator.

The oil temperature displayed in the instrument cluster comes via the CAN bus from the digital engine electronics to the instrument cluster. On the S62 engine, the oil temperature shown in the instrument cluster is displayed as a mean value of the oil temperature measured value of the oil level transmitter and the dual coolant temperature sensor (temperature engine exit).

Sixth post on this page: https://www.bimmerforums.com/forum/s...retrofit/page3

[g300d]

In this M5 thread is more discussion saying oil temp is calculated, and that the oil level/temp sensor can cause a low calculated oil temperature report.

https://www.m5board.com/threads/oil-...sensor.618211/

ECS sent replacement under lifetime warranty. These Bremen sensors are junk - don’t waste your time. The first was completely defective, the second at least is giving a reading for the oil level but oil temp is reading way low now. Ordered the BMW part. This is fully warmed up after hour of driving. Gauge is not faulty.

I was looking at aftermarket sensors and since the Bremmen thermostat is working well I was considering the Bremmen sensor but apparently it gets mixed reviews. Hella's arent too well regarded also.

[Homerlovesbeer]

My oil temps on 4.8is are about 85 degrees C going by the oil temp gauge. Why would that be a problem?

[g300d]

Hi Homer, that temp I believe is ok. I wouldnt mind that temp, maybe ranging up to 95c would be nice.

I'm honestly only now really looking at oeltemp because I am wondering how the Bremmen 95c stat will affect it.

My concern is I'm not sure how accurate my readout is now, with what seem like improbable oeltemp readings ignition on/off.

Could you happen to look at your oeltemp at ignition position 1 and car running if they are different and/or show any improbable figures? I know ktemp doesnt do that for sure and I dont think oeltemp should but maybe it does since its a value from a couple of sensors like Andrew suggested.

[Homerlovesbeer]

Yea mate,

I'll have a look and post later today after taking the other half to work.

EDIT:

No oil temp value found when using my OBD-II scan tool, only engine water temp at the block and at the radiator.

Average at the block is 101.2°C when moving and 102.7°C while stationary.
At the radiator is ambient temp until warmed up which seems about 50-60°C

[g300d]

Brilliant, thank you!

[g300d]

Here's a vid of what I'm talking about. The oeltemp value suddenly goes into negative digits when I switch off the ignition. Then turning it to position 2 it goes back to "normal".

https://imgur.com/a/aK7Wb6S