Member
Hi all,
I've been getting a low oil pressure light when the car is warm and idling. The second I rev, the light disappears. Out of caution, i took the car off the road and began to troubleshoot the issue. I hooked up a pressure gauge which read lower than normal pressure.
Since then i've changed the following:
Oil pump
Rod bearings (which were a little worn, nothing excessive)
After the above, pressure increased slightly at start up, but the problem persists when warm. The light still comes on
I next swapped out my oil filter housing
A lot of time and money later, i'm stuck at square one. I've done a fair amount of searching and i've seen that this mystery is somewhat common. Can anyone shine some light on the issue? Or give some advice on what I can do to resolve?
Let me know if there's any more information you need from me
Thanks in advance
Member
Been there, had that -- TWICE. Once with an M52 and then an S52. Solution? Complete rebuild. Probably a combination of things. I chased my 328 for months and rebuilt it. SOLVED. When the 229k mile S52 started doing this, I didn't mess with it. I have a block and rotating assembly on hand, so bored it and built it up with everything new except the crank and rods. Refreshed the existing head, bolted it down to the fresh block, and finished the swap.
1) How many miles on the engine?
2) What oil are you using?
3) When I rebuild M and S 50s and 52s, I replace the piston oil squirters. If they stick open, they can reduce idle pressure. ONLY fix is to do a tear down as they are held in place by the main bearing shells in the block.
4) With time and miles, the crank MAY wear a bit (but usually does not), but the main and rod bearings will. Again -- rebuild.
5) If you do rebuild it, have an experienced machinist mic the crankshaft journals -- middle and sides as well as three axis' of the journals. That way you know that they are not the issue.
Member
Thank you for the response although it was the opposite of what i was hoping for.
160k miles on the car
Shell Rotella 5w40, changed every 3k miles. Switched to a thicker oil since
Member
At this point, heavier oil won't help.Originally Posted by djsk8r1218
There are two Shell Rotella oils. One is diesel only, and the other is general purpose. That said, they really are bot focused on diesel applications. If you rebuild, switch to Castrol Syn or Mobil 1. And 10w-40 vs 5w anything.
Apprentice w/#yrs. exp.
Before you go tearing into the engine, try replacing all O-rings first-#3,#6,#7,in oil filter housing:
http://www.realoem.com/bmw/enUS/show...diagId=11_1288
as failed or missing O-rings affect oil pressure.
Member
Oil squirters have broken springs in them.
98 M3 sedan
Member
When I first purchased the car I came to the forum to research what oil to use.. From there on out I used Shell Rotella T6 5w40. My mistake
MIKYZZ4 O-Rings #3, #6, and #7 have been changed out at every oil change. They are not the problem but thanks for the input.
All signs point to tearing into the engine at this point
Member
The only way THOSE would cause the problem is if they were removed. And, BOY, what a mess THAT would be !!!!!!!!!
BTW, I have sent you a message.
Member
Any other thoughts on here? A rebuild has been suggested but I'd rather not go that direction until i find the root of the problem
Member
Sadly, whatever the root cause may be is buried inside the engine.
Member
The owners manual says the oil light may flicker at idle when the engine is not and this is ok. That would be with 5W30 synthetic. It probably should not flicker with a thicker. Have you replaced the oil pressure sender for the light? Have you checked it's wiring and grounding? It grounds through the sender so if you have a bunch of thread tape on it, it might not ground well. I know you tested with another pressure tester but some are better than others. Can you verify the one you used with a mityvac or air pump with gauge?
I assume you have no leaks, at least external ones.
Inside the motor there are the usual culprits. You did the oil pump. I assume you checked the pick up tube carefully. They can crack at the pick up end. There is a reinforced version you can buy. Squirters are hard to test with the engine fully assembled. Any engine work done recently before the problem started.
Just want you to test everything before rebuilding the motor. They are pretty sturdy motors that wear well but they are also about 20 years old now and may need refreshing.
Member
I dug through some old records and the original owner was using 5W30 from the start. I used 5W40 and recently started using thicker oil at the onset of this issue. The oil pressure sender was the first item I addressed and i will check with my mechanic to see if he's checked the wiring/grounding. No leaks, noticeable at least.. No engine work done recently. Motor sounds great and if I hadn't seen the light, I wouldn't think anything was wrong.
Member
I am going to get rocks thrown at me, but the 5W-30 may have been the death of the engine. And just to make sure people are REALLY throwing BIG rocks, I detest Euro spec 0W-40. I have NOTHING but problems with it. Low oil pressures, lifter issues, etc. On M ans S 50s and 52s I always put WIX filters and Mobil1 10w-40 -- and that really is fine all year round unless you live in cold climates, and then 10w-30.
So, for ever it is worth, there is my 2 cents worth.
Apprentice w/#yrs. exp.
I've read through many oil threads, everyone has their preference,
so no stones or rocks from me, as most persons know what works for their specific circumstances.
I have used BMW 5w30 for years, no complaints besides price.
so after some research, I have recently been using Castrol EDGE 0W-40 A3/B4 Full Synthetic Motor Oil-European formula.
As with the BMW oil, no complaints. I recommend it as an alternative to BMW oil.
My $.02 for those seeking alternative to factory fill.
Member
Later model cars, such as yours, certainly have different requirements than the old horses, such as E30, 36s, and so on. I have a 2002 525 Touring, and it is running 5w30. Similar engine, but different enough.
Member
We have noticed a vibration in the seat at about 1k RPM's. Any possible culprit?
Member
Dude honestly, get an oil analysis done before you go tearing into your motor. Unless you have money and time to burn.
https://www.blackstone-labs.com/
The test kits are free, analysis is like 20 or 30 bucks IIRC.
Read this thread: http://www.bimmerforums.com/forum/sh...e-at-Idle-Info
CN: the light might flicker and come on at idle when the engine is hot, even if nothing is wrong because BMW
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Last edited by Nate047; 09-22-2017 at 05:10 PM.
Member
That could be ANYTHING. Driveshaft, guibo, center support bearing, motor or trans mounts.
Member
All signs are pointing to the oil squirters.. common consensus seems to be that it's not worth rebuilding the motor for this issue alone.
Member
How warm are you getting? I tend to get some intermittent flicker after running the car pretty hard, the car doesn't ever see temps >210, but when they get near, I get a light flicker. A blip of the throttle and it's gone. I add a touch more oil when this happens and go about my drive. It doesn't come back. I've installed an oil pressure gauge and my pressures don't drop below 9-10 psi while daily driving. I haven't worried about it since the gauge and the car still runs beautifully.
How hot are your oil temps getting?
Member
I've never measured my engine oil temp. What's the best way to do this?
Member
I have a friend with a 325 race car (177k miles) and my M3 has 221k, and both exhibit this flicker to some degree when hot (his car worse than mine).
He is an auto industry consultant, and has access to an old "retired" race engineer to help him track down problems and make the "right" modifications to his car (the consulting business uses the engineer, so he get's free access when they're working on actual work).
Mine only recently started doing this when it's above about 105 ambient (in Texas), but his car had been doing it in cooler temps for a long time (and constantly) once the car is warm. Any uptick in revs and it goes away. We haven't looked at the squirters, but he did the same thing djsk8r1218 did and more (E46 M3 sump, pickups, etc; rod bearings, oil pan, thicker oil, etc).
After chasing this for a while at one point he mentioned it to the race engineer, and he told him not to worry about it. He had installed a manual gauge, and it showed something like 4 PSI (where the light's threshold is just higher than that, somewhere like 5-7 PSI).
The engineer's explanation in a nutshell was that while low oil pressure isn't the greatest thing ever, at idle there is no load on the engine, so the low pressure isn't a big issue. While I don't recall reading what pbonsalb mentions about the light flickering in the manual (I read it a LONG time ago), this old race engineer seems to agree with BMW that it's not a big deal.
I will also second the Blackstone recommendation. Do an oil analysis with every oil change and you'll know where you stand. While this situation with my car bothers me, at 220k miles it's to be expected, seems to have been foreseen by the OEM, and my Blackstone reports confirm that I'm not seeing any rod or main bearing wear. So while it bothers me, it's not worth a full teardown at this point, and not even worth a lightweight version with a rod bearing refresh.
-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.
Member
If you change to an 850 rpm idle, the problem may also go away. Must be done in the tune.
Member
I had the same problem and it was the oil pressure switch, but as you said you hooked it up to an actual gauge and it was reading low. You are not the first person to spend all that time chasing the rabbit and ending with the light still on.
It definitely does say in the manual the light can come on at idle, but realistically you never saw this problem this much in these cars ten years ago when they were a lot newer.
Member
In a nutshell, that sums it up. The "fleet" is aging. I have been through this twice. The first time I could see the light on at 700 rpm idle in mild weather with oil temps well below 150f. The oil pressure gauge showed sub 5psi. That engine was pulled and replaced with a different freshly built engine. I had replaced the squirters (a few were not closing), rods and main bearings. At 200-210 deg oil temps with 10w40 Mobil 1 the engine was holding 10 psi oil pressure at idle. The original short block has been fully rebuilt and is in another car running nicely. The second engine was a 227k M3. Same deal on pressures. Again, the short block was replaced. The fresh one holds 10 psi at idle in 90 deg+ weather with 200+ oil temp on 10w40 Mobil 1.
The gamble of running a "wounded" engine is that once the pressure is sub 5psi at idle, the long term prospects of damaging important (and expensive) parts increases. Specifically, crankshaft as well as cams and trays. That said, unless one has a car that is a) in extremely good condition and worth saving, or b) there is an emotional need to save the car, or c) a + b and an M3 (which are increasing in value), the cost of rebuilding an engine exceeds the return on investment. Even if one can do their own work, a full refresh (without boring and pistons) will cost about $800 (+/-) plus head rebuild. So ........
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