Low Oil pressure at idle

[mikenarlock1]

Ok so i just bought a 04 bmw 325i and ive noticed the oil light flickers when at an idle but as soon as i give some gas to it the flickering ceases. So i gave it a test since i drive a manual i threw it in neutral while the vehicle was moving to see if it does it then and as soon as the rpm's dropped to below like 500 it started flickering again...this was at 70 MPH. Ive googled this and ive seen that a LOT of people have had this issue with both manual and automatic styles in many different makes of bmw's. Any suggestions on what my next move should be?????

[2bms]

I intermittently have this same issue in my 2003 330i. It seems the warmer the weather, the more often it happens, especially when sitting in traffic. Oil pump is fine, oil level is fine. I've tried different grades of oil. I'd love to find a cure if anyone can impart some wisdom.

[E30Alpina]

Had the problem on my E36, oil pressure sensor was the culprit. Located on the back of the oil housing.

[vertbmw]

Assuming you have checked the oil level and verifyed that it has the correct oil in it, verify that you are loosing oil pressure.Get a manual (non electric) oil pressure gauge hook it up to where the existing sending unit is. If the manual gauge reads low at idle you have a mechanical issue. If the gauge reads normal the problem is probably the sensor.

[sprintman]

Are you using the correct spec (LL01) oil?

[2bms]

Are you using the correct spec (LL01) oil?

Yup, currently using BMW's own oil, have previously tried Mobil 1.

[sprintman]

M1 is fine as long as it isn't XW30.

[mikenarlock1]

Ok well im not sure what oil is in it now but i took it back to the dealership to get it checked out.... sorry im new to bmw's but ya i took it back to the dealership to get it looked at and they said they couldnt find a leak and that they had previosly used the red dye test. the light stopped flickering since i picked it up from the dealership today. could the red dye have caused an issue with the sensor maybe???

[RNeil]

You did not say anything about a leak or low oil level. Obviously you need the correct amount of oil. If you don't have that problem and the dealer is adding dye and looking for a leak, don't go to that dealer.

[mikenarlock1]

Ok heres my update to it. the reason we were looking for a leak is because we saw a spread on the left side of the engine. At first looked like someone made a mess while changing the oil. but me and the mechanic started tearing the intake box and things out and we found it. it seems as tho is a small very slow leak comming from the sender/reciever unit(sensor) u could definitely see the seal had worn enough to allow small amounts of oil to leak into that sensor. so were going to replace that part and hopefully that is the issue. Ill update when i know more but it seems that would be the problem

[RNeil]

My point is that unless a leak leads to a low level, that is not the cause of your low pressure.

[mikenarlock1]

Point taken. I get that much. Im fairly good with cars just new to bmw's. Oil level isnt dropping at least not noticebly. And as i said before the oil pressure LIGHT flickers below 1000 rpms anything above that and the light turns off. replacing the unit did not solve the flickering light issue so im taking that guys advice and using a mechanical oil pressure gauge to see if the oil pressure is actually dropping or not.

[IWannaBMW]

Oil pressure sending unit most likely

[2bms]

Oil pressure sending unit most likely

Maybe. I replaced this today (attempt number 83 to fix this problem). So far no warning light. I'll keep you posted.

[mikenarlock1]

I replaced the sender unit. Light came back on

[2bms]

I replaced the sender unit. Light came back on

Damn. I was hoping this was the fix. I replaced mine the other day, and haven't had a light come on yet, but I haven't driven in traffic yet. That's when mine comes on, when it's warm outside and I'm in traffic. What are you going to try next? If this hasn't fixed mine, I'm at a loss.

[mikenarlock1]

Im going to see. Im using the manual oil pressure gauge to see if the pressure is actually dropping. If it is its the oil pump if it isnt its a sensor. ill let you know when i find out what the hell is going on with this thing. thats my pissy face lol

[ptarditi]

Red light or yellow light, yellow light is oil level sensor which is very common. Leaks on the drivers side of the block are oil filter housing gasket and usually the high pressure vanos line, even if the vanos line isn't leaking yet it will and i needs to come off by the intake solenoid to do the housing gasket.

[Broox]

Red light or yellow light, yellow light is oil level sensor which is very common. Leaks on the drivers side of the block are oil filter housing gasket and usually the high pressure vanos line, even if the vanos line isn't leaking yet it will and i needs to come off by the intake solenoid to do the housing gasket.

Just gonna quote this. This man speaks the truth.

[2bms]

Aaargh. Saw the dreaded light flicker again today, albeit briefly. I really thought I'd fixed it by replacing the sender, but obviously not. Ptarditi, it's the red light. Only flickers very briefly when at idle and the weather is warm. I'm stumped for ideas, but I HATE seeing that light. Checked oil level again - normal. In fact my car doesn't seem to use any oil at all. And just to reiterate, I am using BMW Fully Synthetic, and I change it every 6 - 7k. Mikenarlock1, it sounds as though we have identical problems. If you come up with anything, please let me know, and I'll do the same for you.

[ptarditi]

I hate to be a pedant, but... I've abused a lot of cars even drove a tii with a bad con rod bearing (would only death rattle under heavy load) but I wouldn't drive or even run my motor if I thought I didn't have adequate oil pressure. Until you can get a reading from an actual mechanical pressure guage I wouldn't run it. You've got too many places for bad things to happen. Besides t5he oil pump one place I've seen people mke a common mistake is with the oil filter on N52, N54/55 the currnet 6 cyl there is an o-ring on the stem of the filter cap tht gets replaced at every oil service. I belive the M54 has this o-ring but it doesn't come with the filter and o-ring kit for the cap. Take a look at that o-ring and if by any chance you are using a non-oem filter. My daughter thought she was being attentive to her 330 and was saving me from do any more work on her car (so I could babysit) and had an oil change done at lube dr., I checked the filter the next day and it didn't even fit. Good luck I don't know wht a replacement cylinder head is but I know the vanos unit runs about a G.

[mikenarlock1]

I got what ur sayin man and i understand that the vanos be the problem... and i just replaced the sender unit that sits on the drivers side of the engine behind the alternator and the oil filter im not sure about. But yes 2bms it would seem we have the same exact problem. which as it turns out isnt uncommon in bmw's volkswagons or even mercedes. So what im doing is using the mechanical oil pressure gauge to get a readout. if the oil pressure isnt dropping its the sensor but if it is its the god damned oil pump.... and for u and my sakes i hope its not that pump 2bms.

Aaargh. Saw the dreaded light flicker again today, albeit briefly. I really thought I'd fixed it by replacing the sender, but obviously not. Ptarditi, it's the red light. Only flickers very briefly when at idle and the weather is warm. I'm stumped for ideas, but I HATE seeing that light. Checked oil level again - normal. In fact my car doesn't seem to use any oil at all. And just to reiterate, I am using BMW Fully Synthetic, and I change it every 6 - 7k. Mikenarlock1, it sounds as though we have identical problems. If you come up with anything, please let me know, and I'll do the same for you.

But ptaidi is right u should avoid running your bimmer until u figure out what it is. im using my wifes bimmer right now until i figure it out

[2bms]

Ptarditi, you're not a pedant, I value your advice. I was driving the car for a couple of days when I thought I had the problem fixed, but now it's apparent that I still have a problem, it is parked. I am lucky enough to have 3 vehicles at my disposal, so not a problem. I do my own oil changes, so I know the filter is correct and o-rings in the right place. I had an indy mechanic who I have known for many years check my oil pump a few weeks ago, he said it was fine. So, I'm at a loss. Any advice will not be taken as pedantic!

[mikenarlock1]

Ptarditi, you're not a pedant, I value your advice. I was driving the car for a couple of days when I thought I had the problem fixed, but now it's apparent that I still have a problem, it is parked. I am lucky enough to have 3 vehicles at my disposal, so not a problem. I do my own oil changes, so I know the filter is correct and o-rings in the right place. I had an indy mechanic who I have known for many years check my oil pump a few weeks ago, he said it was fine. So, I'm at a loss. Any advice will not be taken as pedantic!

Alright 2 bms got an update for you. Used the manual pressure gauge i am dropping pressure at idle. Were going to replace the oil pump. itll take a few days to get the part ill update u when i replace it. try the oil pump

[2bms]

Mike, thanks for the update. Interesting information. My indy mechanic told me my oil pump was fine, but I'm not sure how he worked that out. So if replacing your oil pump fixes your problem, I'll go ahead and do the same. Sorry to be using you as my guinea-pig!