Oil light malfunction?

A few days ago I heard a tapping from the engine, sounded like lifter tap. I went to check the oil and it was somehow 2.5 quarts low! I refilled the oil and the noise is gone and the car seems to be running much more smoothly.

The oil light has never come on over the past 6 months since my last oil change. It seems as if the oil has been leaking from the bottom of the filter housing. I have replaced the o-ring there and seems like the leak is fixed.

Question, is the sensor that is responsible for turning the oil indicator light on malfunctioning? If so, where is it located and how can it be tested?

It's possible that it has failed completely, but it should at least throw some oil light on the dash.

The oil light does come on on the dash when I start the car, but it has never come on indicating low oil.

If the oil light comes on for 10 seconds around 15 seconds after you start the car, that's an indication the sensor is bad.

i have the same problem, when i start my car up it goes yellow then turns off 15 seconds after. this means the sensor is faulty, my mate diagnosed my electrics and it came up as faulty oil sensor. it is located at the bottom for the sump pan.

Originally Posted by Solidjake

It's possible that it has failed completely, but it should at least throw some oil light on the dash.

You'd think. As stated, OP, the legend here is that it will trigger a malfunction. Mine had been coming on like Tangent said.

If you were this low and the oil light didn't come on, then it would be the first such failure I recall reading about.

No problem, though, as your solution is pretty easy. Check your oil!

You were 2.5 qts. low? That's really bad for the car. But that's great for you, because otherwise I wouldn't have known you're not checking your car nearly enough.

Think of it as a huge lawnmower. You'd check the gas and oil before starting it, wouldn't you?

(Edited--removed my diatribe about finding leak. But, who did the last oil change? Jiffy lube? That o-ring should be put on properly--mine hasn't leaked and I do my oil myself!)

You need to open your hood way more often.

Take care of your car...check all your fluids, belts, filters...and don't be frightened to open the hood, look, smell, feel, hear, touch the engine and listen to what it's telling you.

Face Munich, read pages 1-25 of Owner's Manual, pour 1 oz. of oil on your hair and leave it like that for a day, and you'll be fine!

Originally Posted by Solidjake

It's possible that it has failed completely, but it should at least throw some oil light on the dash.

When sensor's fail they tend to throw some sort of code or light.

OP you should be able to test the sensor. If you have a bentley manual you should be able to find the resistance specifications for the sensor. Break out the multimeter and test it

I've thought that basically that the yellow light coming on at start up is the car telling you that it has no idea your of your oil level.

The O-ring at the bottom of the housing will not fix the leak you observed. You need to replace the oil filter housing gasket, Item 8 in the attached diagram -- this diagram is for my car, your car may be different, and you have to look it up...
http://www.realoem.com/bmw/showparts...88&hg=11&fg=30



THE YELLOW OIL LIGHT
The light comes on before the car is started to tell you if the light works, and comes on after the engine is stopped to tell you the oil is low. The error in the system is that it comes on for a few seconds after the car is started, then goes out again. The Owner's Manual does not give a very good description of the light, except that when RED, the situation is serious enough that the car whould be stopped immediately.