[shariz]

So, bought an E90 LCI (2010) 318i a few weeks ago. Test drove it and checked it as thoroughly as I could upon purchase and it was absolutely fine and smooth. As soon as I buy the car I get it a full service (it was close to needing one) and then went about using it for my daily commute of 20 miles each way on weekdays. My local mechanic who serviced it even commented on how it was one of the cleanest examples of an E90 he'd seen in a long time after his full vehicle inspection.

Around a week and a half after purchase (300 miles ish) the oil pressure warning light comes on about 30 mins into my daily commute. I pull over and turn the engine off and check the oil level, all good and bang on 'max'. I start the car up again after a little bit and it sounds absolutely fine (as far as I can tell), no knocks or rattles and idles at 600rpm. Also the warning light is gone, so I drive the rest of my commute and call my trusted mechanic who serviced the car a week earlier. He gave me the usual advice to make sure I do not drive it if the light continues showing but was a little puzzled when I said it seemed absolutely fine and wasn't losing any fluids. Tells me to bring it in that evening.

I take the car to him, no warning light on my way back. He drives it around a little and doesn't think there's anything wrong. ECU shows log of the light going off, so he clears that and asks me to keep him posted as he thinks just a bit of muck from the old oil blocked the sensor for a bit.

The next day the warning light goes off again 30/35 mins into my commute, but again goes away as soon as the engine is turned off and on again. The car still performs perfectly, but this warning light always appears around 30-40 minutes into my daily commute (the only drive I make of that length) each way. I take it back to him to leave it with him for the night, and he goes about draining the oil and checking it as well as filters etc.

The next day he says there was a fair bit more of a black carbon type mucky build up on the filter and engine than expected, but no metal or anything at all to indicate engine wear. All the typical failing points such as some o-rings that are known to perish after a fair few miles had been replaced already and were in perfect shape. He thinks it might be some gunk from the old oil just coming through and blocking the sensor occasionally, and said he ran the car for 30 minutes and the light didn't come on. He speculates that maybe the old owner used oil fortifier to thicken up the oil and that might be sticking in parts, but can't be sure. Gives me back the keys and asks me again to keep him posted just in case the light comes back.

That was yesterday, today I go about my commute and sure enough the light pops on right at the end of my trip (seems to come on marginally later now?) at about 40 minutes in. Goes away after the engine is restarted and the same thing happens on my trip home.

I plan to take the car back to him, but in the mean time I want to ask here what anyone might think is causing the oil pressure warning to go off like this for no apparent reason? It's the weekend now so I can't really get back to him til Monday. It is very consistent on when it occurs, but never dependant on how I'm using the car (has happened when sitting still and when cruising at 60). My 20 mile commute is mostly one big A-road where I usually do between 40-60mph as it's twisty in parts so speed varies a bit but is fairly consistent for long periods of time. I want to get this sorted as I'd rather only have the light come on if something was seriously wrong, unless I'm missing something here?

TL;DR My E90 oil pressure light comes on around 35mins into my commute and goes away as soon as the engine is restarted, but at the moment there is zero apparent reason why, and mechanic doesn't see why yet either after doing some light checks. Any ideas on what is causing it?


(By the way, I went for the 318i because of insurance (I'm 18), I'd have gotten a 6 pot if I could haha.)

[Welcome to NBA Jam]

Have you replaced the oil pressure sensor? They do go bad from time to time. The part itself is about $5 USD and very easy to access, so it's worth replacing just to see.

[shariz]

Have not replaced the oil pressure sensor yet, I think that might be my mechanics next move. Was just wondering if this was symptomatic of a faulty sensor (this was one my immediate thoughts when this first started happening) or if it could be something else that I don't know about. Cheers, as you mention the sensor is cheap (less than £20 here in the UK I think) so may as well change that out and see what happens.

[maxoutput]

The later 318 and 320 engines were known for the timing chain tensioners breaking up. The cars were taken in and the plastic tensioners changed but rarely if ever were the sumps removed to fish out the broken bits of plastic. These bits get caught against the oil pump pick up strainer in the sump causing the engine oil pressure light to come on and cause oil starvation.

When the engine is turned off they drop away only to get sucked back up after the engine has been run for a while again

[labrador]

Maybe the engine ingested the serpentine belt, and the previous mechanic did not drop the oil pan to remove the strips caught in the oil pick up tube. I was looking for a member's pictures but could not find it.

[shariz]

Originally Posted by maxoutput

The later 318 and 320 engines were known for the timing chain tensioners breaking up. The cars were taken in and the plastic tensioners changed but rarely if ever were the sumps removed to fish out the broken bits of plastic. These bits get caught against the oil pump pick up strainer in the sump causing the engine oil pressure light to come on and cause oil starvation.

When the engine is turned off they drop away only to get sucked back up after the engine has been run for a while again

This sort of response is exactly why I posted this here. Thank you, I'll relay this on to my mechanic when I next speak to him! I'm just curious as to why it didn't happen when I drove the car the 3 hours back from where I bought it or for the first week of driving but even so this seems to fit the bill.

Originally Posted by labrador

Maybe the engine ingested the serpentine belt, and the previous mechanic did not drop the oil pan to remove the strips caught in the oil pick up tube. I was looking for a member's pictures but could not find it.

Didn't think of this, cheers! General consensus is there might be debris in the oil system it seems that's more than just some congealed old oil from potential oil fortifier useage like my mechanic current suspects.

[maxoutput]

I don’t think the n46 or later n43 engines were known for ingesting drive belts like the 6 pot varieties do.

The strainer blocking can be sporadic if it’s due to the bits of tensioner. I’m not saying it is that 100% but it’s quite common so high on the hit list

[Cruiser124]

Originally Posted by labrador

Maybe the engine ingested the serpentine belt, and the previous mechanic did not drop the oil pan to remove the strips caught in the oil pick up tube. I was looking for a member's pictures but could not find it.

Yeah it could look like this! Although I'm not sure if this is common with your particular engine.

[shariz]

I'll know more after the weekend has passed, would take a look myself but this time of the year my free time is literally non-existent. Thank you all for your comments, it's appreciated.

[tobacole]

hi guys, pleaseeeeee any update on this problem, I've literally got the same exact problem, supposed to take it back to the dealer this weekend.

[marvinstockman]

You need a way to measure the actual oil pressure. You can install a mechanical oil pressure gauge temporarily, and monitor pressure.

[tobacole]

The mechanic at the dealer measured it after running the engine for about 30 mins and showed me the gauge... the pressure was normal... and just for good measure he swapped out my oil sensor for another one...10 Miles into my journey home the light came back on

[CDirks]

Originally Posted by tobacole

The mechanic at the dealer measured it after running the engine for about 30 mins and showed me the gauge... the pressure was normal... and just for good measure he swapped out my oil sensor for another one...10 Miles into my journey home the light came back on

Assuming the sensor they replaced isn't faulty, the other likely factor would be oil pressure.

Any of the potential hazards noted earlier in the thread could be the culprit. The only sure way to check would be to drop the oil pan and inspect the oil pickup and pan for debris that might be present

[gbalthrop]

Originally Posted by tobacole

The mechanic at the dealer measured it after running the engine for about 30 mins and showed me the gauge... the pressure was normal... and just for good measure he swapped out my oil sensor for another one...10 Miles into my journey home the light came back on

Those of us in the US are NOT familiar with the 320i. What engine do you have in your vehicle? If you are NOT sure, please provide the last 7 characters of your VIN and we can look it up.

US vehicles with engines such as the N52 only used an Oil Pressure SWITCH which completed a ground signal to the warning light, meaning that a false signal could occur if the wire from the switch to the DME came into contact with chassis ground.

Other engines such as the N43 had more complicated Oil Pressure SENSORS which measured pressure variations and were more than a simple switch. Some of those Oil Supply Systems incorporated an Oil Pressure Control Valve (Y6384 in Schematic) as shown in this TIS Schematic for the N43:
https://www.newtis.info/tisv2/a/en/e...-valve/vkTKNMY

Apparently the N43 engine had some history of Timing Chain Guide failure which could block oil passages. If you have an N43, you should be aware of those potential issues as described in this overview:
https://en.wikipedia.org/wiki/BMW_N43

Each of the BMW engines has its own strengths & weaknesses, and you should make sure whoever is diagnosing/ working on YOUR vehicle is up to date on that specific engine, and knows how to use test equipment such as INPA to properly monitor Sensor Input to DME, & Oil Pressure Setpoint & Actual Pressure, if it is regulated by DME.

George

[tobacole]

thanks guys.... I'll get that checked out and update on the progress

[Andystobbs]

Does your light come on immediately after a run at high speed driving? Ie. As soon as you slow down and the rpms drop?

If so and if its an engine like N43 with variable oil displacement, and the pick up strainer is clear then its probably the pressure control valve.

[TheKebabMan18]

Originally Posted by Andystobbs

Does your light come on immediately after a run at high speed driving? Ie. As soon as you slow down and the rpms drop?

If so and if its an engine like N43 with variable oil displacement, and the pick up strainer is clear then its probably the pressure control valve.

a couple weeks back i was driving my n47 quite hard and as i pulled into my driveway the same warning came up, engine oil was on max aswell and no codes came up, this is the only time ive had the warning in the couple months ive owned the car. i am interesed to see what comes of this thread.

[fozzi]

Originally Posted by TheKebabMan18

a couple weeks back i was driving my n47 quite hard and as i pulled into my driveway the same warning came up, engine oil was on max aswell and no codes came up, this is the only time ive had the warning in the couple months ive owned the car. i am interesed to see what comes of this thread.

Likewise, just had the same issue 5 miles from my destination yesterday evening.

Any updates?

[TheKebabMan18]

Originally Posted by fozzi

Likewise, just had the same issue 5 miles from my destination yesterday evening.

Any updates?

Hasn’t happened since, I do still give the car a hard time occasionally but it seems to have been a 1 time thing, I’ve heard that these cars can be really temperamental over bumps and such so I think I just sent it alittle too hard that day personally. Being my first car tho it definitely got my heart racing

[Lefty81]

Originally Posted by shariz

I'll know more after the weekend has passed, would take a look myself but this time of the year my free time is literally non-existent. Thank you all for your comments, it's appreciated.

Have briefly scanned the site and am amazed at what info is available to members. WOW.

So I have just bought my E91 318i and am having this exact issue as SHARIZ.
Did we ever get a outcome to the issue they were having and what was required to get it resolved.


Look forward to any advice and thanks in advance!

[J05HR]

Originally Posted by Lefty81

Have briefly scanned the site and am amazed at what info is available to members. WOW.

So I have just bought my E91 318i and am having this exact issue as SHARIZ.
Did we ever get a outcome to the issue they were having and what was required to get it resolved.


Look forward to any advice and thanks in advance!

I have a 318i and the engine was in a bad state, I found a place a very reputable company here in England to rebuild the whole engine. Engine was really smooth, ran like it was brand new. It Was about a 70 mile drive home and about 5 miles from home, the oil pressure light came on so pulled over and called them right away. They said its completely fine as they have the tools to check the pressure and a known fault on that model and there's nothing wrong with it and the only thing you can do is disconnect the oil pressure switch. I said what happens if there's a genuine problem and you need the oil pressure switch sort of like the boy who cried wolf and he said that if that switch genuinely comes on then the damage is already done by then and you would hear rattling anyway. So it may be nothing and just a common fault usually when driving at high speeds and then really slowing down, usually on an incline or decline.

Here is everything they did on the rebuild

CARRIED OUT ENGINE REMOVAL AND STRIP DOWN TO INVESTIGATE SUSPECTED
TIMING CHAIN GUIDE FAILURE,
IDENTIFIED BROKEN TIMING CHAIN GUIDE PIECES IN OIL STRAINER CAUSING OIL
STARVATION AND NUMBER 1 CONNECTING ROD TO HAVE BEEN HOT,
CARRIED OUT FULL ENGINE OVERHAUL INCLUDING, REPLACEMENT CRANKSHAFT,
CONNECTING ROD, OVERHAULED OIL PUMP, BEARINGS, TIMING CHAIN ASSEMBLY,

CARRIED OUT FULL ENGINE OVERHAUL/REPAIR INCLUDING;-
RECONDITIONED CYLINDER HEAD WITH;
VALVE STEM OIL SEALS,
CLEANED AND RESEAT VALVES,
HONED CYLINDERS,
REPLACEMENT CRANKSHAFT,
MAIN BEARINGS,
CONNECTING ROD BEARINGS,
REPLACED CONNECTING ROD,
REPLACED PISTON RINGS,
REPLACED OIL PUMP,
OIL PRESSURE CONTROL SOLENOID,
TIMING CHAIN,
GUIDE,
GUIDE,
SPROCKET,
TENSIONER,
OIL PUMP CHAIN,
GUIDE,
TENSIONER,
SPROCKET,
ASA BOLTS,
VARIOUS GASKETS, AND SEALS,
SPARK PLUGS,
OIL,
OIL FILTER,
ANTIFREEZE,
REGASSED AIR CONDITIONING,
REPLACED WORN CLUTCH ASSEMBLY,
RESET ENGINE RUNNING VALUES TO FACTORY SETTINGS,

[percyfranc@gmail.com]

Hi shariz Did you manage to get this Fixed, I also have the same problem