"Stop Engine Oilpress" Message at low RPM
 

I changed my oil yesterday, and today I drove my kids to school. The car drove fine until we pulled into the school lot (about 4-5 miles) and the red oil pressure light comes on and it says "STOP ENGINE OILPRESS." I stopped it immediately and checked the oil, and it was low but still on the dipstick, and couldn't find any leaks or signs of losing oil.


I drove to Napa just down the street and noticed that if I kept the revs above idle the lights and message would go away. I put a full quart in it and drove to work, but the behavior is exactly the same.



I found a few threads that show many people having this same problem for extended periods of time. Particularly this first one, which describes having the problem and it possibly being related to an aux fan problem (I also disconnected my aux fan yesterday and drove to work without it, without thinking):

https://xoutpost.com/bmw-sav-forums/...e-oil-lev.html


I just wanted to ping the brain trust -- I don't think there is any actual danger to the motor right now, right? Especially since I just drove over 10 miles without it seizing up or spinning a bearing.



My car has just rolled over 130k and I just changed the oil with 5w40 euro blend full synthetic and a Mann filter. The previous oil I had left in for 9 months and about 9,000 miles, but it was because of a lot of highway road trips and normally I change it after no more than 6,000, always using quality filters and euro blend full synthetics. I have had the car for almost 40,000 miles and seven years. I also replaced the CCV system 6 years/35k ago, and see a little sludge on the dipstick and oil cap but can't find any other sludge in the system. I don't know if these things are important, just wanting to point them out.



Any help is appreciated! I have been putting a lot of time and effort into keeping this car up over the past year, and I'll be really bummed if it's going to keel over on me.

Well, I'd start by reconnecting the aux fan. I don't really see how that's linked, unless they're saying that the engine overheats that much with it disconnected, but hey...

Next, I'd replace the oil pressure sensor.

If it persists, I'd be suspicious of the oil pump or another oiling problem. Are your revs dropping more than usual? Thicker oil might help if the issue is a weak oil pump.

I definitely would NOT be commuting in it until I figured out if it's actually oiling the engine properly or not. These engines will go some time with zero oil pressure under gentle conditions, but not that long.

Also note that I reinstalled the engine fan yesterday (the engine-driven fan) after leaving it off all winter like I always do. I also broke the radiator shroud and removed it yesterday, which is why I disconnected the aux fan connector. I wonder if I might have damaged the oil pressure sensor wire during that work? But even if I did, why would it only trip the low-oil-pressure alarm at idle speeds? Anything over even 1,000 rpm or so, the alarm light goes away.



I also should note that it gave me the "Check Engine Oil Level" message a couple of times as well.



Could either a faulty oil level sensor or oil pressure sensor be tripping BOTH the oil pressure and the oil level alarms?

Definitely no change in the behavior of the engine at all. I reconnected the aux fan, but forgot to reset the code with my foxwell (not sure if it resets itself after it faults). I will do that before I start it next.

Idle is when your pressure drops the lowest. The BMW sensors are set real low, so if they're working properly and they go off, you basically have no oil flow.

They're totally separate sensors, so I wouldn't expect them to interfere that way. They also work completely differently. The oil pressure sensor is just a switch.

The only way that I would feel at all good about driving through this is if I hooked up an oil pressure gauge and confirmed that pressure is actually good. But it's probably less work to just change the warning sensor and see if that solves the problem.

I agree, that is why it seems like it can't be a broken or unplugged sensor. Perhaps it could be something like the sensor is plugged up with gunk, but why would that happen all of a sudden?




Also agreed, but then why did I not get a low oil level light until after the car had warmed up and was throwing low oil pressure codes? (Especially since the oil is all the way to the top of the normal range on the dipstick.) The two problems have to be related.



One thing I was wondering, I made sure the big rubber O-ring on the oil filter housing is installed, but could the little O-ring in the middle cause oil to pool in the housing or something?I also used this Mann filter part number which I believe I've used before. If they sent me the wrong oil filter could it cause this problem? P/N 11427512300



I am trying to think how something could cause both of these problems at once here. Low oil pressure isn't something that could cause a low oil level at the same time, unless the engine was out of oil, which it's not.

$25-30 I picked up oil pressure gauge to be able to confirm. On e70 I can read oil pressure through obd but I don't think that's possible with e53.

Plugged up or just slightly less sensitive.

Oil pressure is generally MUCH higher with cold engine (cold oil). It's not just a couple psi. If it throws the error cold, then your oil pump has lost prime and probably needs to be replaced.

I would replace the sensor and then report back. The range of possible causes for this issue are too wide to address without figuring out if the sensor is working.

Oil pressure gauge prob less $ and you will have for future testing. I think I had to unplug the go-nogo sensor on wife's n63 motor to measure

Check those o-rings. If one of them has failed part of the oil pressure is lost directly back to sump.

Thanks for all the input guys. I think I'm going to drive it home this evening since I am at work and it made it here safe. And just make sure to keep the revs up. I'll check things out and order a new pressure sensor tomorrow as well as anything else I feel like I should replace. Also, I can park the car for at least a week.



I don't think oil pumps can lose prime unless the suction pipe has a hole in it, or the pump has a chunk taken out of it. They are positive displacement gerotor type pumps.

I will check this tonight, thanks for the suggestion. (I don't have keep my 34mm socket in my car, or I would do it here.)

Have you tried to check the resistance values on on the oil pressure switch itself?
That is one sure way to know if the sensor is bad before replacing it.
I think Bentley has the correct resistance value.
I also vote for checking the oil pressure independently and go from there.

The pumps can wear out. I've had that experience personally with S54 pumps.

If the Vanos seals are leaking you can have low oil pressure at idle, especially hot. Try adding something to thicken the oil a bit like STP just to help with diagnosing the problem.
Typically though, the light will flicker at first and get progressively worse.

Where do the VANOS seals leak into? Would this be visible from outside the car or do they leak back into the crankcase?

Also would this happen instantaneously? I have never seen the low-oil-pressure light before today and now it is happening whenever the car is warm and at idle.
I will check this tonight. I do have a Bentley manual. Fortunately I can park the car for a few days. Is the sensor located in an accessible place?

Just drove home and it drove fine. It didn't start popping up the oil light until I was a couple of blocks from home. I just kept it in gear and shut it off at stop lights. I will park it for a few days until I can diag the issue. Unfortunately I did check and the Foxwell won't tell me the actual oil pressure. I will try with BMW Scanner tonight to see if that will show me.

The Vanos seals leak into the crankcase so nothing visible. The oil feed for the Vanos is an external line so might try pinching that off to see what happens. I guess it is possible that you actually blew a Vanos seal which would explain your symptoms.
You won't get an oil pressure reading from a scan tool because there is no sensor for the DME to read it.

Gotcha, I was thinking it was a pressure transmitter, but if it is just a switch then that would make sense.



Is there a way to diagnose a blown out VANOS seal? Would it throw a Vanos code?

I think the best thing to do would be to pinch off the Vanos line while watching the oil pressure or the oil light. I haven't tried this myself though.

Yeah I actually just was searching on bimmerfest and found the exact same suggestion. Will try it tonight. Thanks!

Man, the bimmerfest E39 forum is just chock full of people with this same problem on M54 cars. Few resolutions but a couple say replacing the pressure switch solved it. No reports of spun bearings or seized motors, even though most of them have driven on it.

Yeah,

Old problem who has been discussed 100 x on bimmerfest E39, E46 etc.

For the most part, you are OK. Just do some research and enjoy the reading.

My 1998 528i case was an "easy" one...leaking sensor.
Replaced the oil P sensor, all is well now...

I saw a lot of your posts. What's your thoughts on driving it before I find the fix? There seems to be a lot of different causes.

There's a places you can add a "T" onto oil pressure to read directly. It's pretty risky to drive guessing the pressure switch is reading wrong

Oil pressure switch is on the oil filter housing.
#13

https://www.realoem.com/bmw/enUS/sho...diagId=11_2201

FWIW, the oil pressure switch on these things is a commonly used part in the BMW family - like many of the sensors, i.e. air temp, dual-engine temp. etc.

And the oil pressure switch is known to be crap. I had one fail on my BMW Dakar motorcycle, giving a similar fault - low oil pressure light at low RPM. Turns out the switch fails internally and oil leaks into the contacts.

I don't recall many folk here having trouble with them but it would be my go-to first step!

the fact is that the switch works, because the error isn't always there. What is also telling is that the errors start appearing with warm (thinner) oil, at idle, which is a clear situation where low pressure can occur if there's something wrong. My guess is the sensor is fine, and you have a leaky vanos seal or a leak near the filter that causes low-flow pressure errors.

I know a switch is cheap and good to check, but my feeling is that it's probably something else.

Not quite - once faulty, the switch only works with higher oil pressure (than it is spec'ed to operate at) - and that's the issue.

At least sometimes. ;)

They do this when they start to fail. Before he starts tearing his engine apart, he should do this.

I did put in an order with FCP for a new switch ($13 shipped for the OE brand) and I think I can just park the car until I get it in.

"Stop Engine Oilpress" Message at low RPM
 

I saw that same deal. My temp on my n55 seems to read low and I'm wondering if the sensor is just sending slightly incorrect signal. I had thought my tstat was reading wrong but my coolant pump failed and I replaced the tstat with it (n55/e70) and the temps still read lower than target and lower than oil temp by a fair amount. Wife has n55 in her 535 so I'll have to take a test drive and compare

PA soft tells me the LCM says I have a "Thermal oil-level sensor defect." That's referring to the level sensor in the bottom of the pan, right? This didn't come up on my Foxwell.



Nitpick: It REALLY bugs me that PA soft and my Foxwell have different capabilities AND give me different error codes. My Foxwell won't even detect some modules that PA soft will (such as the LEW). Drives me absolutely batty.

OK fellas... I pulled out the oil filter to inspect all of that business.. and it looks like the plastic tube that goes through the middle of the oil filter came off (broke off?) and got thrown out with the old oil filter? How I could have done something this dumb, I don't know, but it's totally missing. Bone headed move on my part. I am guessing this is the culprit. Got another one coming. Will keep it parked until it comes.

This is the main reason I like the Knecht/Mahle filters with rubber ends. They are so much easier to remove and install (compared to hard end like Mann) without the fear of breaking the centre tab (or actually doing so). Knecht used to be the OEM filter when these came to market.

Glad you found it. I wouldn’t have thought to look at that.

Wow...I thought that tube...around which the filter fits (snugly) was metal...
I have never heard that it can separate from the oil filter housing....

I need to look on RealOEM

There is a metal part at the bottom which I think is a part of the OFH. The piece that is missing is the plastic part which I thought was attached to the cover. However it appears that it must have been a separate piece. Or maybe it broke off, I don't know. The plastic piece has a mesh tube and then two small O-rings at the bottom.

Yeah the whole center portion of what's in the picture apparently detached and went in the garbage with my oil filter.



I normally get a plastic bag and just put the filter in it and throw it away immediately. Didn't notice this time that I took out more than just the filter. Boneheaded move. Lucky I didn't cause any real damage.

I got a replacement oil filter housing cap, and installed it, and no more warnings!


I think this one is what an IT guy would call PEBKAC (Problem Exists Between Keyboard And Chair) or in gearhead terms, "need to adjust the nut behind the wheel."



Thanks all for your patience helping me out.



Also, don't buy a third-party oil filter cap. It only cost $16 shipped but was almost impossible to install. It fit tightly but took me a half an hour to get it threaded on.

aka a PICNIC (Problem In Chair, Not In Computer). :rofl:

Glad it's sorted. :thumbup: