RS2 - Oil Warning Light at Idle - 1.0 bar

[K Simmonds]

Item 6 in that diagram is the oil temp sensor, item number 3 is the relief valve itself.

Is 10w-40 not an option state side?

15w-40 should also be fine especially in the south, I wouldn't let the for Diesel applications put you off as long as it's got the appropriate accreditation's, though I can understand your reservations about using it in an RS2.

[Bimmerod]

As you say hook the gauge up to the one of the two sensor holes, whichever you can get at the best.

5w-40 could be a touch on the thin side depending on ambient temperature, kinda depends if your in Texas or Minnesota, but even then it should really be okay if it's decent oil. What's your oil temperature gauge saying when you've given the car a good spirted run and what's the ambient cold start temp range?

10w-40 should be fine just about everywhere but don't know how easy that is to get in the USA.

My RS2+ spec 3B seemed happiest (very consistent pressure readings & quiet engine) running on Fuchs Titan 20w-50, I'd just be sure to take it easy until the oil was up to temp, but it would get a dam good thrashing once warm.

Am running the same oil in my RS2 with no issue's, I just let it warm up before giving it any serious boost, doesn't take long say five min's in the summer, ten in the winter. That said it doesn't really get that cold over here, rarely below -5C / 20F, normally between 5C and 25C or 40F and 75F in freedom units. It would probably be a bit on the thick side for the more northern states.

Can you try another F22? As it could simply be this playing up and triggering the warning when it shouldn't as well as giving inaccurate readings under some conditions. Even if it's been replaced it could be a faulty unit.

Otherwise perhaps it could be the relief valve as mentioned above, very much doubt it's the shells if the engine is running smoothly and quietly.

I am in California so the temps never really get that cold nor would I be driving in any inclement weather anyways. Yesterday the ambient temp was around 68F/20C and the oil temp gauge never went above 90. It can get to be 100F here but once again, I probably won't be driving the car in either extreme.

10w-40 is easy to get, that is readily available. I should be able to get the 15w-50 Motul 300V here as well - https://www.motul.com/us/en/products...ition-15w50--2. Otherwise I would have to order the Fuchs https://www.opieoils.co.uk/p-68898-f...ngine-oil.aspx and pay for the shipping to the states.

I will order a couple new sensors since I have to take quite a bit of stuff off to access them. It doesn't look like the factory OEM sensors are available, I assume it's ok to run an aftermarket unit?
https://www.fcpeuro.com/products/aud...nsor-035919561
https://www.fcpeuro.com/products/eng...-crp-056919081

Let me know your thoughts

[Bimmerod]

5w40 is a bit thin. Can you get 10w40 or even 15w40?
Yes, put the oil gauge on the smaller oil sensor.
Try removing the oil temp sender under the block and clean the oil relief valve. Mine had black carbon grit in it after engine rebuild.

I can get this but it seems like everything labeled 15w-40 is for "Diesel" applications - https://rotella.shell.com/en_us/prod...synthetic.html

This is the oil relief valve / temp sender you are talking about ? -
oil pump.JPG
Thanks

[K Simmonds]

As you say hook the gauge up to the one of the two sensor holes, whichever you can get at the best.

5w-40 could be a touch on the thin side depending on ambient temperature, kinda depends if your in Texas or Minnesota, but even then it should really be okay if it's decent oil. What's your oil temperature gauge saying when you've given the car a good spirted run and what's the ambient cold start temp range?

10w-40 should be fine just about everywhere but don't know how easy that is to get in the USA.

My RS2+ spec 3B seemed happiest (very consistent pressure readings & quiet engine) running on Fuchs Titan 20w-50, I'd just be sure to take it easy until the oil was up to temp, but it would get a dam good thrashing once warm.

Am running the same oil in my RS2 with no issue's, I just let it warm up before giving it any serious boost, doesn't take long say five min's in the summer, ten in the winter. That said it doesn't really get that cold over here, rarely below -5C / 20F, normally between 5C and 25C or 40F and 75F in freedom units. It would probably be a bit on the thick side for the more northern states.

Can you try another F22? As it could simply be this playing up and triggering the warning when it shouldn't as well as giving inaccurate readings under some conditions. Even if it's been replaced it could be a faulty unit.

Otherwise perhaps it could be the relief valve as mentioned above, very much doubt it's the shells if the engine is running smoothly and quietly.

[Tractor Dave]

5w40 is a bit thin. Can you get 10w40 or even 15w40?
Yes, put the oil gauge on the smaller oil sensor.
Try removing the oil temp sender under the block and clean the oil relief valve. Mine had black carbon grit in it after engine rebuild.

[Bimmerod]

Appreciate the responses, I will look into getting a mechanical gauge to see exactly what's going on. Where is the best place to hook that up? I imagine in one of those two sensor holes?

I know there has been a lot of discussion about "oil" based on the number of threads I see. Just curious if there has been a consensus on what grade to use for spirited everyday driving? The engine was refreshed less than 5k ago, complete teardown/rebuild and haven't given any issues up to this point. So is it really necessary to use 10w-50 if the motor is fresh?

PS- Looking at the notes it appears they used 5w-40 oil for the last change.

Pretty sure those two oil sensors were replaced "just because" since they were going through everything.

What I can't figure out is what is telling to Oil Warning Light to come on @1k at idle? If the F22 is set to go off at 0.3 bar and the F1 at anything below 1.8 bar above 2k then it's strange. What should the normal idle RPM be? Is 800-850 too low? Because if I raise the RPM's a little the OP goes right up and the warning light goes away.

Getting 10w-50 here in the states is looking to be a challenge as no one really makes that grade.

Let me know your thoughts

[Tractor Dave]

Yes, agree with above. What grade oil (I think you call it weight over there) are you using? These engines don't like thin oil.

[K Simmonds]

As above, confirm what the oil pressure is doing with a mechanical gauge then go from there.

[varia]

I would make sure the car has the proper type of engine oil then check the pressure with a (decent) mechanical gauge).

[rustybullethole]

Could be a weak oil pressure relief valve, or the valve slightly off of its seat, I.e. not closing fully. Could be slightly worn bearings.

[Bimmerod]

I'm having an issue with my Oil Warning light coming on. On initial startup oil pressure is at 5 bar then comes down to around 3-4.5 while driving. After going for a short drive and getting things up to operating temps, the oil pressure drops to around 1.0 bar at idle (around 800 RPM). This is reading the factory gauge of course.
If I bring the RPM's up to about 1000 the oil pressure goes up to around 1.3-1.5 and the warning light goes off. Once I let it idle again it drops back to 1.0 bar and the warning comes back on.
I am getting normal OP readings while driving so I'm a little stumped?
I know the larger F22 OP Switch should only come on if the OP drops below 0.3 bar and the smaller F1 OP Switch should only turn on the warning if it drops below 1.8 bar @ 2k RPM. If I hold it steady at 2k the OP is around 3.2-3.5 bar and no warnings on.
Just trying to see if I should just replace both OP switches while I'm down there or if one or the other is the root cause of my issue. Other than the warning coming on at idle the car sounds and runs without issue.

Let me know your thoughts.

Thanks,

Bimmerod