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Red Oil Pressure Light

76K views 39 replies 16 participants last post by  jdstrickland 
#1 · (Edited)
I'm having some difficulties with my 2003 325i sedan. The car has almost 90,000 miles on it and recently the red oil pressure light came on while idling at a red light. The light would turn off once I accelerated. I've done a lot of searching on here but don't know what else to do. I brought the car into my local BMW dealership and had they performed a pressure test ( results came back that pressure was good). They said I needed a new oil pressure sensor (located in the engine). I replaced the sensor, however, the light came on the first time I drove it a few days later. I noticed the light only comes on when the car is idling in Drive or Reverse and that the RPMs seem to be hovering around the 500-550 mark at this time. If I put the car in Park the RPMs increase slightly and the light goes out. I called the dealership again and they want me to bring it back in to be examined again. They mentioned it could be another sensor located in the oil pan? Im just wondering whether or not it is just the ICV. Any suggestions?
 
#6 ·
As odd as it sounds, one thing I'd look at is the end of this sensor wire in the e-box. It heads into one of the multi-connectors in there.

I found oil under my connector and my mechanic said he'd seen it before where the sensor leaks into the wire, pushing oil up inside the insulation...that might affect the voltage it's showing.

Also, nothing personal, but there's also a temp sensor on the ofh...I have no idea if they're interchangeable, but it wouldn't surprise me if they were...so you sure what you took out looked the same as what you put in? You sure you reconnected whatever you disconnected?

Also, since you're having the dealer change your oil, I'd mention that I think your car might get to be very expensive to maintain...oil is very easy to change and it gives you a chance to look around underneath yourself...which is always a good idea!

Among my other random thoughts, I'd say you should check your pulleys and belts--and since your idle is low (s/b around 700) I'd read up on cleaning the icv/tb and making sure you're otherwise up on 'Inspection' work--plugs, filters, etc.

Sounds like because you're idling so low, your oil pump isn't doing the work the car wants it to do. I doubt the oil is wrong, but it couldn't hurt to ask...

Oh, finally, don't think anyone mentioned this but you should check your oil level, of course! Next time you change the oil yourself, btw, might want to calibrate your dipstick in case it's the wrong one. If your oil level is just at max level on level ground in the a.m., and everything else is fine, then you might consider trying to add just 1/4 qt. of oil.

The red oil light can be oil pressure, but it can also be just a low oil level.
 
#7 ·
I just checked the oil this morning, it is right on the top notch of the dipstick. As for the oil pressure switch, I had the dealership replace it so if the problem persisted I could bring it back and (hopefully) not pay to have any more diagnostic fees since the problem wasn't properly diagnosed. I will have them take a look to see if there is oil under the connector...oddly enough, when I had the pressure switch replaced last week they also shampooed my engine which I didn't notice until I arrived home. I think my car is due for an Inspection 2 within the next 9000 miles so it could be something as simple as spark plugs or filters. Also, I checked my invoices, they read that the dealership uses Bulk BMW Syn 5W30.
 
#10 ·
^truth. I wish misinformation wasn't so prevalent on BMW forums :sigh:


Could be a few things, first thing you need to do is mechanically see what pressure is actually coming to the sensor.
Is it a flicker only when hot?
 
#14 ·
meh. i would just bump the idle to get the light to stop flickering. i have seen guys at the dealership go round/round with this stuff..... oil pumps/senders/clusters/etc.etc.
 
#19 ·
Yeah I will tell the dealer to take a look and adjust the idle speed. I hope they don't to charge me another diagnostic since they obviously were incorrect with the sensor. Its very annoying to see the oil light come on. My friend has an identical car (same year, options, colour...) and the dealer ended up making them get all new senors and switches AND replace the oil pump..and the light still come on occasionally!
 
#15 ·
I had the same problem, your idle speed is too low! The oil pump is not turning fast enough when you are at idle. What happens is your engine reaches operating tempature, the oil is hot and thins out, less oil pressure. An idle speed of 500 rpm is too low and the oil pump is not pumping as fast, oil pressure light starts to flicker.
You need to increase your idle speed wich can be done with software. I did not replace my ICV I used a Vedis scan tool to increase the idle speed. Take it back to the dealer and have them make idle speed adjustments.
 
#16 ·
Just had this problem, It was the Oil Level Sensor. Easy DIY change it on our next oil change. Red oil light would flicker when coming to a stop and stay on when in idle. Eventually turning off when i gave it gas. Only happened occasionally when the car was warm and about 6000 miles on the oil.
 
#17 ·
Yea..... not the oil level sensor.....


Also I don't think the ISTA can do an idle adjustment last time I checked. I know an autologic will :)
 
#20 ·
Like I said I don't think an ISTA can adjust it, you need to find an Indy with an autologic
 
#24 · (Edited)
BMW I6 engines have long had very low oil pressures at idle. The M54 (according to Bentley) runs around 7 PSI at idle. It's not uncommon to see 5 PSI at idle on BMW I6 engines. This is very low in the great scheme of things. I'm not sure what the threshold for the light is. It wouldn't surprise me if it was around 2 PSI.

Did they give you the pressure readouts? I'm assuming they followed the BMW protocol and put a pressure gauge in place of the pressure sensor on the motor and verified the pressure. What was it at idle and at elevated RPM? Again, 7 PSI is what you're supposed to be seeing at idle. It should be 59 PSI at elevated RPM.

Raising the idle speed is a bandaid if there is a real problem. The light is there for a reason. Putting a bandaid on the issue to make the light go away doesn't solve this. It just creates a false sense of security.

-Verify the correct oil is being used
-Verify the correct filter is being used
-Verify the oil pressure readings they got and how they were obtained

It seems unlikely that you got a bad oil pressure sensor right out of the box. The more likely explanation is that you actually have a pressure issue, and this should not be taken lightly. It can destroy your engine in short order. Causes can range from a bad oil pump, to the oil pump nut being off the shaft, to worn internals, to clogged oil passages.

Get some more info. I wholeheartedly disagree with the suggestions to raise the idle speed to mask this issue. If the pressure is actually low at idle, it will be comparatively low at elevated RPM. If the pressure is out of spec, the reason behind it needs to be diagnosed.
 
#27 ·
Yes, for me it did. problem started at 70k but I just ignored it since the problem would only happen when the car was really warm or over 6000 miles on the oil. I replaced the sensor at 100k and since then I haven't seen the oil pressure light. Its been over 9000 miles since my last oil change.
 
#31 ·
Hi, I have the same issue. The oil pressure sensor was changed but still there. The light goes on after about 20 minutes of driving meaning this happens when the oil is already hot and thinned out. My idle is fine about 600 to 700 RPM. Any suggestions where I should look?
 
#34 ·
I was at my local dealership on Thursday, 07/19/2012, and of the oil on display in the parts department, not one bottle claimed to be LL-01. All if it was BMW-branded oil, and not a single bottle of any of the various weights said that it was LL-01. Maybe they hide the LL-01 in a secret room, although I seriously doubt this is actually the case.

They had both full synthetic and dino oil, and there were several different weights. My guess is that some was for mortal cars, some for the M cars, and some for BMW morotcycles, although the part about the bikes is just a guess because I don't recall that this dealership carries the bikes. It could, I just don't remember seeing any.

PS
My dealership is owned by a consortum of Boris Said and Hendrick Motorsports. I saw Boris the other day when I was there. I did not know, but he's something like 6'6".
 
#36 ·
I own a BMW e46 from 2003 with M54B22 engine with 90k milles and i have the same problem. Low oil pressure at hot idle. Since then i changed the oil pressure sensor, oil, filter, filter hausing, oil pump, main and rod bearings(machined the crankshaft at the correct spec for the bearings), pressure reliefe valve in oil pump, lower part of engine gastets kit, oil separator,oil squirters(all 6 of them.....the spring in 3 of them was weekl) but the problem still persist. The pressure was mesured with a gauge every time and the readings are around 0.4 bar at hot idle (idle is around 700 rpm). At 1000 RPM the pressure increases very fast, around 1 bar and so on.....at high RPM reaches the maximum spec 4 bar. At cold idle(when i first start the car) the pressure is around 1.1 - 1.2 bar. I also did the VANOS seals from beysan systems with no improvement. The engine temperature is normal....no overheating and starts and runs fine, the idle is rock solid...:(
 
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