low oil pressure light on e36

[ricardo jamin]

I’m having an intermittent problem with my e36 M3(has 130k miles). Since there are a lot of them in autocross, I’m hoping there is someone who familiar with the issue I’m having.

About two week ago I saw my oil red light(the low oil pressure indicator) briefly flickers. Just briefly, less than a second and they its gone. When it happened it was idling waiting at red light.

I brought the car to edge motorworks. They concluded its not a real low oil pressure because the engine sounds fine. I explicitly asked if they did a pressure test, and they said they didn’t because everything else didn’t indicate low oil pressure. They noticed there is a bit of leak around the pressure sensor. They think that was the problem and recommended to replace it. I had them replace it.
They also mentioned other leak in the car, but I think they are minor. I just did oil change a month ago and didn’t see any obvious leak either in top or bottom of the engine. They didn’t make any recommended action in this so I think they think its minor too.

Well last night I saw the light flicker again. same as before just flicker for a second and its gone. Car was also in idle.

One thing I notice is I think my car has low idle rpm. sometime the needle just barely above the 500 rpm. could this be culprit? is there a way to make the the idle rpm higher?
I’m thinking of getting oil pressure gauge myself. It seems pretty cheap, I’ve seen it sell for $30 on amazon. this should be pretty easy procedure on the e36 M3, right? just plug it in where the sender unit, yes?
Any tips what to look for when doing the pressure test?
I might give edge a call again but I want to gather more evidence so they can be more focus in their second diagnosis.

Anyone has any experience troubleshooting this with their e36 M?

[Dave Dunwoodie]

Mine (’97 M3 – 156K miles) flickers at idle when the engine is warm too. Has for the last 30K miles, and two oil pressure sensors. If you see the light at anything other than idle, I’d be concerned.

[Andy Daniels]

Doing a pressure test is a good start. That’ll quickly eliminate the sender as a possible culprit. I’m surprised Edge didn’t do that while they had the old sensor out, since that’s where you’d stick the pressure gauge, anyway. While you’re in there, clean the contacts on the connector and put some dielectric goo on it if Edge didn’t do that themselves.

A search of various BMW forums unfortunately reveals that a fairly wide range of things could be causing this, so you’ll have to do some investigating to narrow down the cause. One simple possibility is the oil filler cap, though I’d expect to see the pressure warning at other than idle in that case. Going to a heavier oil might do the trick, too.

More specifically identifying the circumstances under which you see the flicker will help definitely narrow down the possibilities. I.e., only when engine is hot, only at idle, when weather is warm, &c.

Good luck!

[ricardo jamin]

@dave, thats good too know that this is not necessarily bad news for the engine. I guess around 130k is when this thing starts to show up for both of us.

@andy, yeah I’m surprised they didn’t take pressure measurement too. I googled this issue before, and only found a handful post. And all of them don’t have resolution.

So far it only happened when its idle. I only seen it flicker three times before I posted this. twice before I brought it to Edge and once after. However driving home tonight I actually seen it flicker few times 🙁
The good thing they are all always when its idle. Always when I put the gear to neutral. and it goes away if I rev the engine a little bit.
I’ll probably call Edge tomorrow.

[Dave Dunwoodie]

I bet it goes away when you turn on the AC too. AC raises the idle slightly.

I had my car in at Bavarian Motorsports twice to fix this problem. I don’t remember what they did or replaced the second time, but when I picked up my car, the problem remains the same. I’m interested in what you find out.

[Hal Dorton]

I’ve not been on here recently. Just run thicker oil or add some Lucas Oil treatment.

[ricardo jamin]

Thanks for the idea Hal.

I have appointment with Edge tomorrow(Tuesday). I’m curious what their take on it.

[John Kim]

Ricardo, what weight oil are you running and how high are you running the oil level? For example the Mobil-1 5w-30 is supposed to be a little bit too thin when hot for our cars (I run Mobil-1 0w-40 or Total Energy 5w-40).

I’m new to my E36 M3 but based on Internet lore, two other possibilities are cracked oil pickup tube or tired oil pump seals. But I’m not sure how common those really are. As mentioned by others, doing a pressure test or installing an oil pressure gauge would help.

And the favorite E36 racing 3rd possibility: You’re driving really high-G left-hand sweepers and sloshing all the oil to the right side of the pan, leaving the oil pickup high and dry (all while re idling at a stoplight).

[ricardo jamin]

Thanks for the advise John.

I dropped the car this morning and just got a call back from Edge.
They rechecked the car and didn’t find anything suspicious. They replaced the oil with a heavier one. My original oil is Mobil1 0w40, and I think they replaced it with 15w50.
They let the engine warm up and the light is still on 🙁
It’s a real bummer, so the next step they suggested is to take the oil pan off and diagnose from there.
Hopefully just an oil pump seal or cracked picked up tube, as you mentioned. I really hope its not a rebuild time.

[ricardo jamin]

Just got a call back from Edge to pick up my car.

First, I’m a test/quality engineer and to be honest I’m not totally convinced of the fix. I think there are assumption being made without solid evidence. On the other hand, I understand the reality of troubleshooting is sometimes you can’t always get solid evidence. So I’ll give them the benefit of the doubt that they have abundance of experience to rely on from making these assumption.

So here’s what they did.
They took off the pan and found the bearing and journal was fine. so that’s a good news.
Oil pump also visually looks fine but they replaced it anyway because they said they’ve seen this goes bad from age. They put everything back together and still see it flickering. I’ve seen it flickering at first but the last night I drove it was solid red. Edge said when they reproduced the problem it was solid red. so they think the oil pump helps.
Then they bump up the rev. And they haven’t been able to repro the issue after bumping up the rev, so it’s deemed fix.

I suppose if I didn’t see the problem again then I’m happy, even though probably its just from bumping up the rev. If I see the problem again, at least I can cross off the bottom part of the engine.
I’m crossing my fingers its fixed.

[Andy Daniels]

By “bump up the rev,” do you mean that they adjusted engine idle speed upward?

[ricardo jamin]

yes they raised the idle rpm speed. very slightly, I’m guessing maybe just 50 rpm. right now its idle around maybe 550 or 600 rpm.

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