Getting STOP OIL PRESSURE When Stopping Car with Hot Engine?

[LuckyBill]

I just had a lot of work to my newly-purchased 159K 2003 530iA M-Sport, my first BMW. Oil & filter change (Liqui Moly 5W-40), coolant change, replaced CCV system, DISA valve, fuel filter. Also replaced intake manifold, valve cover, and oil pan gaskets. Also replaced the oil pressure sender as it was giving me a code. I took the car to a BMW mechanic but it turns out the mechanic that did this work was not familiar with my type of BMW.

I had already replaced the plugs & added Dinan coilovers.

Next day I drove the car for ten minutes, but when I pulled into a parking lot just before I turned the key off I was startled to briefly see STOP OIL PRESSURE in the dash. Five minutes later I'm in the car, stopped at a stop sign & saw that dreaded warning again. Stopped the engine, turned it on again and got it home without another warning. It's been sitting in my garage since.

I only get the warning when the engine is hot and I've stopped the car. Searching tells me this may or may not be serious in this circumstance. The warning only happens when the car is stopped when the is engine hot. Some people live with this, but I'm not that certain I should do that.

One solution I've is to raise the idle by 50 or 100 RPM - how do I do that? I've read INPA can raise the RPM but its temporary. Can anyone please tell me what diagnostic tool can change my idle RPMs?

Could it be the oil pump?

Any help is appreciated!

[effduration]

You need a better, non-dealer BMW specialist....BMW only sold a couple million M54 engines.

Keep searching on this...I daily drive an '03 530i with 415k miles and orig engine.. I think I only had this error once due to low oil... But I believe I read that changing oil viscosities can help.

[LuckyBill]

You need a better, non-dealer BMW specialist....BMW only sold a couple million M54 engines.

Keep searching on this...I daily drive an '03 530i with 415k miles and orig engine.. I think I only had this error once due to low oil... But I believe I read that changing oil viscosities can help.

Thanks. I had them put in Liqui Moly 5W-40 (just added to my OP). Can you tell me what do you put in your 415K miles 530i?

[R Shaffner]

It could be a number of things -- the pump or any thing that hold the pressure in the system.

But I agree about starting with the oil. If you're using something that is -30, try something that is -40, (like 10W-40).

[R Shaffner]

Sorry - I think I was typing when you posted.

It would be nice if you could test the pressure. Or the sensor. (I dont't know that engine.) Easiest thing to try might be to try a new sensor. The current one might just be giving an intermittent false warning.

Something similar kept happening to a 540 owner here. He checked the oil pump and found that the spring in the pressure relief valve was bad.

[effduration]

Thanks. I had them put in Liqui Moly 5W-40 (just added to my OP). Can you tell me what do you put in your 415K miles 530i?

I bought this car 2 years ago with 395k miles and a bad auto transmission. I manual swapped it to a 5-speed (and only then discovered it HAD 395k miles) and have put 20k miles on it since.

I don't go in much for oil brands and usually use the cheapest synthetic I can find, but I use 5w30 in winter and 5w40 in Summer.
I also usually put a quart of ATF fluid in my oil and run it hot right before an oil change, to try and reduce sludge

[ross1]

This is an ominous sign, especially on a just bought car.
Since you've already changed the sensor and symptoms are consistent with a real problem I'd say it's safe to say that the warning is correct but confirmation with a mechanical gauge will be the final arbiter.
Worn crankshaft bearings are usually the cause of low oil pressure. Oil pumps in these seldom fail. Perhaps others can chime in with other potential internal "leak" sources. I'm wondering if failed VANOS seals could contribute enough leakage. Oil pumps don't come loose on M52/4s(ala M60s) do they??
I hope you are Lucky, Bill you're gonna need it.

[blarf]

Oil pumps don't fail that often but yeah the bolt that holds the sprocket to the pump backs off with prolonged high RPM operation. That's mostly a 3L problem though. That'd be the third thing I'd check after the oil level itself and the oil pressure as measured with a mechanical gauge.

[pleiades]

LuckyBill, just an FYI if your issues aren't obviously mechanical. I went through this oil pressure charade with my 528i (M52TU engine), and after a lot of digging around, changing parts, testing oil pressure, tracing connector pins for continuity, etc etc, it turned out to be a faulty warning from an LCM with a toasted chip, apparently caused by a bad (overcharging) voltage regulator in my alternator.

[BimmrMeUpSnotty]

Stupid question, might have missed it, Bill, when the light was flashing on at idle, did you check the oil level?
Another thing, this BMW mechanic you took the car to, what the hell kind of BMW mechanic was that??? A BMW mechanic that is not familiar with an M52/M54??? No such thing as a BMW mechanic with those credentials.

[LuckyBill]

LuckyBill, just an FYI if your issues aren't obviously mechanical. I went through this oil pressure charade with my 528i (M52TU engine), and after a lot of digging around, changing parts, testing oil pressure, tracing connector pins for continuity, etc etc, it turned out to be a faulty warning from an LCM with a toasted chip, apparently caused by a bad (overcharging) voltage regulator in my alternator.

Oil level is fine. I just replaced the LCM4, but thanks for the suggestion.

Stupid question, might have missed it, Bill, when the light was flashing on at idle, did you check the oil level?
Another thing, this BMW mechanic you took the car to, what the hell kind of BMW mechanic was that??? A BMW mechanic that is not familiar with an M52/M54??? No such thing as a BMW mechanic with those credentials.

The mechanic was familiar with BMWs not not specifically my engine. He called the DISA valve an intake manifold actuator. I'm going to have to have the oil pressure checked with a mechanical gauge to know for sure. One thing I've heard is this symptom (low pressure only when car is stopped suddenly when hot) can be caused by a dirty oil pump screen.

[Monark John]

I discovered something similar with my wife's 03 Mini. We got the low pressure warning when hot at idle. I found the spring and filter needed to be oriented in a particular way. No more oil warnings. I am not familiar with the M52 but my 540 doesn't care. I think it's the British heritage of the Mini!

[LuckyBill]

I discovered something similar with my wife's 03 Mini. We got the low pressure warning when hot at idle. I found the spring and filter needed to be oriented in a particular way. No more oil warnings. I am not familiar with the M52 but my 540 doesn't care. I think it's the British heritage of the Mini!

I have a 530i so my engine is an M54. Can you tell me what you mean by the spring & filter have to be oriented in a particular way?

[E39 Newbie]

Oil level is fine. I just replaced the LCM4, but thanks for the suggestion.


The mechanic was familiar with BMWs not not specifically my engine. He called the DISA valve an intake manifold actuator. I'm going to have to have the oil pressure checked with a mechanical gauge to know for sure. One thing I've heard is this symptom (low pressure only when car is stopped suddenly when hot) can be caused by a dirty oil pump screen.

I had this exact problem on my E46, M54 2.5L, 190K-ish when purchased. When hot, pressure light would come on. Raising idle a bit caused it to turn off. Oil level sensor was fine. I pulled the pan and replaced the rod bearings just because PO said he'd run the engine out of oil. He knew nothing of cars, especially BMWs, and he really didn't, he just thought he did. Anyway, the rod bearings looked reasonable, but I replaced them anyway, even though they weren't the problem. Oil pump screen was fine. I replaced the oil pump and, BAM, the problem went away.

BTW, I also use Liqui-Moly 5W-40. I noticed in both of my M54s, after switching to better oil my oil consumption decreased dramatically.

[LuckyBill]

I had this exact problem on my E46, M54 2.5L, 190K-ish when purchased. When hot, pressure light would come on. Raising idle a bit caused it to turn off. Oil level sensor was fine. I pulled the pan and replaced the rod bearings just because PO said he'd run the engine out of oil. He knew nothing of cars, especially BMWs, and he really didn't, he just thought he did. Anyway, the rod bearings looked reasonable, but I replaced them anyway, even though they weren't the problem. Oil pump screen was fine. I replaced the oil pump and, BAM, the problem went away.

BTW, I also use Liqui-Moly 5W-40. I noticed in both of my M54s, after switching to better oil my oil consumption decreased dramatically.

How did you raise the idle? What tool did you use?

[blarf]

How did you raise the idle? What tool did you use?

Raising the idle is pretty much the last thing you should do.

[LuckyBill]

FYI I just spoke to the mechanic that worked on my engine. He had replaced the valve cover gasket & the oil pan gasket. He said the inside looked clean, no gunk. At 159K miles I'm nervous about a crankcase flush but he did say it looked clean.

BTW raising the idle by 50 or 100 RPMs is not a big deal, especially if it saves the engine from catastrophic failure.

[E39 Newbie]

How did you raise the idle? What tool did you use?

I didn't. I just experimented with increasing idle with the throttle, and I noticed the light went out when I raised the RPMs by 100 or so. Until I could tear into it I used some Liqui-Moly oil additive (two cans) to increase the viscosity and temporarily eliminate the problem until I could find time to open up the bottom end and replace the pump.

[blarf]

FYI I just spoke to the mechanic that worked on my engine. He had replaced the valve cover gasket & the oil pan gasket. He said it looked clean, no gunk. At 159K miles I'm nervous about a crankcase flush but he did say it looked clean.

BTW raising the idle by 50 or 100 RPMs is not a big deal, especially if it saves the engine from catastrophic failure.

If you have the answers why are you asking here? Raising the idle will mask the symptoms, not solve the problem. If you raise the idle my prediction is that you'll keep the oil pressure light out until you get a catastrophic failure. As three of us have already pointed out: check and/or replace the oil pump. When you do that, go for the ZHP nut.

[LuckyBill]

I didn't. I just experimented with increasing idle with the throttle, and I noticed the light went out when I raised the RPMs by 100 or so. Until I could tear into it I used some Liqui-Moly oil additive (two cans) to increase the viscosity and temporarily eliminate the problem until I could find time to open up the bottom end and replace the pump.

That's helpful, thanks. Liqui-Moly has a few additives, which one did you use?

[Chedley]

Let me chime in here, though I don’t have any experience with the M52/M54 engine. My car is 540i with V8 M62TU engine.

1. Get rid of that LiquiMolly crap. Revert to plain synthetic 5W30 oil recommended for your engine

2. As many others advised, check the oil pump and screen, and tighten that bolt holding the sprocket to the pump.

3. Check, clean or better replace the oil pressure switch - not the sensor- It is a cheap $10 part, that triggers on and off the oil pressure red warning.

4. Never take your car back to that BMW specialist of yours. I am in complete agreement with BimmrupSnotty : the guy doesn’t know what he is talking about ...

[LuckyBill]

1. I'm using Liqui Moly 5W-40. It's recommended for the M54 and the thicker viscosity compared to 5W-30 means higher oil pressure. The Liqui Moly additive would be a temporary solution to keep the engine safe.

2. Checking the oil pump & screen, as I understand it, means dropping the oil pan again which is not trivial. If it comes to that, I'll do it, thanks.

3. I replaced the oil pressure sensor with this part https://smile.amazon.com/gp/product/B00TOV21FS/
Is there a different sensor/sender I need to replace?

4. I won't be taking my car back there!

[Chedley]

1. Yes, that is exactly what your engine needs and expects with the recommended synthetic 5W30: higher oil pressure. Ok, let's not turn this into another oil thread. :-) But forget any additive.
2. If you've already dropped the oil pan, no need to redo it again just to check the oil pump.

3, Yes, that is the pressure switch I am talking about.

[E39 Newbie]

That's helpful, thanks. Liqui-Moly has a few additives, which one did you use?

I think it was the Viscoplus. I'll check and revise this if I'm incorrect. It took two cans, but it stopped the oil pressure light from coming on at idle for the several weeks it took me to free up my schedule to open the bottom end.

Everybody thinks this stuff is snake oil. But I can attest that both of my M54s used around 1 liter of oil between changes. Since switching to first Motul, and then Liqui-Moly, my E39 (about 170K on the engine) has dropped to almost zero consumption, and my E46 (about 195K on the engine) has dropped by almost 50%. I, too, thought this was all BS, but now I'm a believer.

[ross1]

All this talk about raising idle speed and different oils is putting a Band Aid on a (potential) gunshot wound.
CONFIRM or DENY the low pressure with an accurate mechanical gauge and go from there.
Stick your head in the sand all you want but something is effed.