I am having an issue where my oil pressure light will come on at low RPMs (idle).
This is really strange because it only happens when it is hot outside...
I have been using pretty much the same oil since I purchased the car back in 1997 (Mobile 1 0-40). I have read to try a thicker oil and tried this but it made no difference. This will happens right after a fresh oil and filter change, so it's not that the oil is old.
When the car heats up and it is hot outside (does not really happen when cool/cold outside) the oil pressure light will come on when I am stopped at a red light. When the RPM drop below ~750 it comes on. If I give it a little gas to increase the RPMs the light turns off. This is really annoying in the summer time...
I have already replaced the oil pressure switch twice (the second time to make sure the first replacement was not bad). Still the same issue.
Any ideas?
A lot of us with older / higher mileage cars get this occasionally. I've read the solution is to replace the oil squirters - they can get stuck open, and this is the result. I've seen a lot of people replace rodf bearings hoping it would solve this problem, and it rarely does anything.
The BMW manual says not to worry about a flicker at idle when it gets hot, but it's certainly not fun to see that.
I've had this issue for about 3 years. I've found if I keep the water temp below about 208 I don't have the problem (I don't have an oil temp gauge, so I can't say what the oil temp is when this happens). I've got a high volume electric fan tied to my aux fan switch that usually does a good job keeping the car cool, or gets me cool again relatively quickly if I do get hotter than that, but it's having issues at the moment.
I think an oil cooler would also do the job / help if I was doing a lot of harder driving when it's really hot, but I feel like I'm kind of in that in-between area right now.
Short of rebuilding the bottom end, you either need to decide to live with it or address it by keeping the car cooler than it is right now.
-Josh: 1998 S54 E36 M3/4/6 with most of the easy stuff and most of the hard stuff. At least twice. 271k miles. 1994 E32 740il with nothing but some MPars. 93k miles.
You might want to install a sender that will read actual oil pressure. This way you'll know if you have a real problem or not. Remember, your 0w40 oil is the equivalent of a 40 weight oil when hot, and you don't want to go too much thicker. I think someone makes a 15w50 oil, which might help in the summer months.
Simple things first; did you put enough oil in? I usually use 7 quarts with a filter change. Check the level first.
Then I would install a oil pressure gauge, and monitor what it does.
Low oil pressure can be a number of reasons, but could be serious such as worn main bearings, etc.
Marvin, Mobile 1 makes a 15w-50 which I've run in the past when on the track, though I've used Rotella T6 5w40 on my M3 and tracked it with similar oil temps and pressure.
Last edited by Hova; 06-06-2019 at 09:27 PM.
"Be who you are and say what you feel because those who mind don't matter and those who matter don't mind."
-Dr. Seuss
DIY BMW Tools. Charlie For President
I had the same issue and it was the oil pressure switch. I know you said you already did it, but even the FEBI one did the trick.
I'd suggest replacing the clutch fan. Could be you are getting just a tad too hot on super hot ambient temp days especially when you are sitting idle (i.e. very little air flow). Shot in the dark, but so is opening everything up to do rod bearing and squirters. A clutch fan is $60 and 20 minutes. If a rolled up magazine stops it from spinning it needs to be replaced for sure.
Last edited by realjones; 06-06-2019 at 10:39 PM.
I have this issue too on hot days when the engine temp is fully warmed and come to a stop/idle. 181k miles and running 15W-50. Changing the oil pressure switch twice didn't work.
But I did replace the pick up tube which was cracked with the Z3 one and so far it happens much less frequent (PITA job though). I also run an OBDII style gauge (I forgot the name) but it reads out the coolant temp.
1995 Cosmoschwartz M3/2/5- Daily Driver
1996 Estorilblau M3/2/5- Beater
1998 Cosmoschwartz M3/4/5- Garaged
2003 Sterling Grey M5- "Weekend" Car
Did you replace the gasket at the end of the tube? Perhaps the old gasket was just deteriorated and leaking. The Z3 tube shouldn't affect how oil pressure builds.
If you're experiencing low oil pressure at idle, it's likely the oil pressure sensor, a crack in the pickup somewhere, bad oil tube pickup gasket, faulty o-ring/spring in the pump, or a worn engine.
You guys are using 15w-50 oil and are still getting the light on at idle, this leads me to think that there is either a bad gasket on the pickup tube (or slight crack), or lastly work bearings (unlikely, but possible).
Every time I've dropped the oil pan to safety wire the oil pump nut, I replace the oil pump O-ring, spring, spacer, and control valve. If you already have the pan out to check the pickup tube, I would strongly advise you replace these as well. It's cheap insurance that you'll have peak pressure.
lock ring 07119934625
spacer 11411722836
o-ring 11411722837
spring 11411706809
control valve 11411719937
https://www.realoem.com/bmw/enUS/sho...diagId=11_6017
The spring has some serious force behind it, so be aware of your face and hands. Rebuilding this isn't hard, and significantly cheaper than a new pump.
It should be noted as well that oil viscosity does go down after a certain temperature:
https://www.elephantracing.com/tech-...d-engine-life/
Even at 250F the oil viscosity of 15w50 is about the same as the 30w oil that these cars came from at the factory at 200F.
Most E36's when on the track, or spirited driving see oil temps of around 220 after being beat on with no cooler, so I don't see this being a viscosity issue.
Last edited by Hova; 06-17-2019 at 06:08 PM.
"Be who you are and say what you feel because those who mind don't matter and those who matter don't mind."
-Dr. Seuss
DIY BMW Tools. Charlie For President
1995 Cosmoschwartz M3/2/5- Daily Driver
1996 Estorilblau M3/2/5- Beater
1998 Cosmoschwartz M3/4/5- Garaged
2003 Sterling Grey M5- "Weekend" Car
We had a 540 that would do that check oil, pressure and it would go up 80 psi then suddenly go to the normal reading of 70 psi at idle it was just below the threshold at around 7. It looked like the pressure relief valve was sticking we ran lubimoly engine flush in it and upped to engine oil weight, light never came back on, the car had 180k on it.
"Be who you are and say what you feel because those who mind don't matter and those who matter don't mind."
-Dr. Seuss
DIY BMW Tools. Charlie For President
I don’t have the oil pres light issue, but I do get lifter tick after a track session. At first I was running 5w30 bmw syn oil and overfilling 1/2 qt quieted the tick. Now I’m running Mobil 15w50 but at the correct level. And no lifter tick. My car is strictly for track duty. So if you’re running “normal” weight oil, try an extra 1/2qt which I’ve read doesn’t hurt our motors. Some track guys run a full qt extra.
My 123K mile m3 started doing this after it sat for a winter at the body shop. It would start to flicker low oil pressure light at idle on the first drive of the day/week. If I drive to work after the car sat for a couple of days, it will most likely start to flicker once gets up to operating temperature. On the drive home the same day, there will be no light. I do recall replacing rubber O rings on the oil filter reservoir area, but that's about it. I run Rotella 5w-40. Car isn't not a daily driver, more like a summer toy.
Rotella T6 5w-40 is a great oil, I run it in my M3 and also in my motorcycle. You should read the above and consider getting the problem diagnosed and fixed. Unfortunatly, unless it's a bad sensor, you'll have to remove at least the oil pan to address a pump rebuild, bad gasket, cracked pickup tube, worn bearings, or a leak somewhere. A thicker oil like M1 15w-50 might help, but that is only a bandaid, and is NOT the fix. You should have full pressure even with a 30 weight oil.
"Be who you are and say what you feel because those who mind don't matter and those who matter don't mind."
-Dr. Seuss
DIY BMW Tools. Charlie For President
The owners manual says the oil light may flicker at idle when the engine is hot, and that is for a new car with 5W30. If you have flickering with a thicker oil, I would plug a pressure tester into a port to double check. You could leave a mechanical tester in place for a few days under the hood. Then start troubleshooting by looking for any outside leaks in the pressurized part of the system such as the oil filter housing, vanos line, sensor, primary chain tensioner. Then pull the pan and check the oil pump nut for tightness and the pickup tube for cracks. After that, you are probably down to the pump itself. Disassemble and inspect and rebuild or replace.
If you don’t drive every day does the light go off after 5 seconds? I don’t know the oil path through the engine, but if the car sits, oil drains down. There is a check valve in the head (inaccessible with head installed) that keeps oil in the valvetrain area and I think but am
not certain there is one in the oil filter housing either under the filter or where the housing meets the block. If you pull your cap after the car has sat for a few days, is there oil pooled up around the filter or not?
-Josh: 1998 S54 E36 M3/4/6 with most of the easy stuff and most of the hard stuff. At least twice. 271k miles. 1994 E32 740il with nothing but some MPars. 93k miles.
Car sat for 5 days - oil level is an inch below the top of the oil filter.
I've stumbled upon multiple posts that talk about the same oil light flicker pattern at idle after fan clutch went bad or the car had a fan delete. Mine had fan removed, so I plan on buying a brand new fan clutch and putting it back for shits and giggles.
Very well could be the case, but the data really doesn't show that's the end all. There's likely something else off. Though I will agree that a cooler engine will increase the viscosity.
Oil viscosity of 15w50 at 270F (which I seriously doubt you're over) is the same as 5w30 at 220F, and these engines came with 5w30 factory fill, and didn't experience oil light issues.
https://www.elephantracing.com/tech-...d-engine-life/
Last edited by Hova; 08-06-2019 at 11:21 PM.
"Be who you are and say what you feel because those who mind don't matter and those who matter don't mind."
-Dr. Seuss
DIY BMW Tools. Charlie For President
"Be who you are and say what you feel because those who mind don't matter and those who matter don't mind."
-Dr. Seuss
DIY BMW Tools. Charlie For President
I had to check the first time I heard that, too. And I agree - no one likes to see that, especially when it's a new thing.
And don't come visit me or you'll ruin your perfect record.
I've noticed on my car that this isn't a perfect formula. One day it's 110 outside and my car gets to 208 and the light never comes on, the next day its only 105 and the flicker starts at 203. I don't know if it's an old light switch, the pump relief valve getting a little stuck, or the check valve on the squirters getting stuck open. I've heard the squirters as a culprit before, but I A) don't think they HAVE a valve inside them, and B) I don't know that the orifice is big enough to bleed off enough pressure to cause the symptoms even if there was some valve that wasn't working.
Furthermore, I have a friend with a 325 race car, and he's got a new E46 M3 oil pan and pump and replaced his rod bearings and he's STILL getting the light.
I'd love to get in touch with the engineer who made BMW include that blurb and ask him what the various root causes are.
-Josh: 1998 S54 E36 M3/4/6 with most of the easy stuff and most of the hard stuff. At least twice. 271k miles. 1994 E32 740il with nothing but some MPars. 93k miles.
Yes I mentioned this earlier in the thread because my car had the same issue that was resolved with replacing the oil pressure switch and fan clutch/fan. Two easy afternoon fixes. Despite what the manual says, I disagree that the light flickering is normal...definitely something you are reading a lot more about as the cars age. If a car with 100K on it suddenly starts flickering, having never done so the previous twenty years...something is worn out
Yeah but that's a different story all together. The S54 doesn't use hydraulic lifters like the M50 motors do, so the oil pump volume is less. In being a smaller volume, and more places for the oil to go, there is less pressure as well (measure of pressure is just restriction to flow). Your friend should fix his pump, he's likely not getting over 50psi even at redline. He should shim the relief valve by 1mm-1.5mm on the spring, and also either lathe his own M52 oil pump gear, or buy one from VAC motorsports. You're friend is 100% below 7-8psi at idle if he is using an unmodified pump.
"Be who you are and say what you feel because those who mind don't matter and those who matter don't mind."
-Dr. Seuss
DIY BMW Tools. Charlie For President
I think it's just something they wrote in to skate by having fluke customer complaints. I can see oil getting very hot and losing viscosity, but I don't think any of you have driven your street car that hard. Go do a few laps of Sebring in August, or some track time in Arizona or Texas. The oil temps will be MUCH higher than what you're seeing on the road. If it was normal I think you'd hear all of the people drifting their E36's and racing them talk about it as well.
There is a similar "normal" idea from BMW that 1L per 1,000 km (600 miles) of oil loss is okay too. If you're car looses 1L per 600 miles, you have a problem.
Last edited by Hova; 08-13-2019 at 04:16 PM.
"Be who you are and say what you feel because those who mind don't matter and those who matter don't mind."
-Dr. Seuss
DIY BMW Tools. Charlie For President
Bookmarks