bmw e30 oil check light

Thu Sep 28, 2006 3:01 am

Hi there,
My CHECK OIL light on the CHECK DISPLAY PANEL came on, and when stopping at a garage, the oil level was fine, as-in basically full.

Nevertheless, i put in about quarter pint of oil.. hardly any...

the oil light went out..

i didnt watch the light go out as we poured the oil in, but just noticed a little later it went off...

is this co-incidence?? or is the oil light thingy so sensitive that it can "detect" 100 - 150ml of oil??

any help?

a bit concerned, anything oil concernes me.

the oil on the dipstick looks clean...
the oil level was like half a pint from the top.. that said, this was after a drive... so i never really gave it chance for the oil to run to the bottom of the sump..

any help/advice?

cheers
anton

Thu Sep 28, 2006 5:36 am

it is not very accuurate as oil by nature is very thick and takes its time to get round the engine and therefore to the sensor. my advice is dont trust the light for your oil level, trust your dipstick, the light coming on should only be a reminder that you didn't check your oil. But this light comes on when the level is getting low and is not a reason to immediately panic, just fill er up as soon as possible. my sport would do it after my missus was using it and i didn't do the fortnightly oil/water checks, filling up turned off the light and never had a problem. you will actually be surprised how low the oil can go before things go bad!! (bought a Dodge Durango 2nd hand, next day sevrviced it at our comapny gagrage, it had 1-1.5 litres in there, should have had 5.5!! it was probably running for months with the previous guy like that

and the dipstick did show oil level as being right at the lower level when i bought it.

mrlee

Thu Sep 28, 2006 8:51 am

Oil level sensor is inside a cannister with only two very small holes in it, so it can take quite a while to respond to real changes in oil level.
You can sometimes get a false warning if the car has been parked uphill and leanung to the right (LH wheels on curb?).
As Mr Lee says, its not a reason for immediate panic, except for checking that you havn't got a serious leak.

Thu Sep 28, 2006 9:35 am

as far as i know the oil light will come on if theres no oil pressure...so you ports could be blocked or it could have just been a glitch in the sencor ?

Thu Sep 28, 2006 10:52 am

yz_250 wrote:as far as i know the oil light will come on if theres no oil pressure...so you ports could be blocked or it could have just been a glitch in the sencor ?

Hes on about the oil level light on the check control panel not the oil pressure light on the dash.

My oil pressure light comes on sometimes on tickover, but its had a new oil pump, pressure release valve and switch.

Thu Sep 28, 2006 11:00 am

My oil pressure light comes on sometimes on tickover, but its had a new oil pump, pressure release valve and switch.

Mine did this too - turns out it was the wire for the sensor rubbing on the fanbelt around the front of the engine

Thu Sep 28, 2006 1:48 pm

My oil level light works perfectly - comes on when the oil is on the min marker on the dipstick!! Has done on all my e30's!!
And on my 8 series for that matter!!

Thu Sep 28, 2006 8:30 pm

Intermittent sensor fault if it happens again?

Thu Sep 28, 2006 8:51 pm

Mine came on today... Dipstick showed about 1/4. Chucked in another litre..

I know where it's leaking from anyway....oil control valve...Got the part, will change it on Saturday.

Thu Sep 28, 2006 9:26 pm

Things are complicated a bit by the fact that the sensor in the sump actually contains two level sensors - a static one and a dynamic one, further complicated by the fact that one is short circuit for level OK, and the other open circuit. Got these the wrong way around on my first M50 conversion, which meant the oil check light came on when the oil level was OK, but stayed off when it was low.

Thu Sep 28, 2006 10:06 pm

How's the sensor for reliabilty then??

If it's bad then since I'm dropping the oil this weekend I may aswell remove the sump and change the sensor while I'm at it...

Thu Sep 28, 2006 10:53 pm

Sensors can get a bit gunged inside. Don't need to remove the sump, or even the oil, to remove the sensor, although I wouldn't advise removing it with the oil level at the top of the dipstick.
It lives below the alternator. Disconnect the plug, undo the two nuts and lift it out. Seal is an O ring, so no paper gaskets to worry about.
The sensor will drain very slowly through a small hole in the bottom. After it's finished dripping, place it in a tumbler of petrol, let it fill, then lift it up and drain it again. Repeat several times - a surprising amount of gunge will come out.

Fri Sep 29, 2006 6:51 am

Easy...Cheers.