Would too much oil cause oil light to come on?

[englisharcher]

As the thread title says really.

A friend has a e30 318, he's just been telling me his oil light keeps coming on, I've checked his oil level, and it's one inch over max, would that cause the oil light to show?

[skene]

Pump on its way out? Is the light not the oil pressure?

[james0]

The oil light is usually oil pressure not quantity, an engine can be ruined by too much oil.
In short its probably fked.

[englisharcher]

skene said:

Pump on its way out? Is the light not the oil pressure?

I was thinking that maybe too much oil would cause pressure problems

[skene]

englisharcher said:

I was thinking that maybe too much oil would cause pressure problems

I think the light would indicate low pressure as opposed to high pressure. I'm honestly just thinking out loud though

[Jimbo.]

Oil being whipped up by the crank, mixing air into it and reducing pressure? Low pressure triggers the oil light...

EDIT: Maybe he put more oil in upon seeing the oil light, so it was goosed beforehand...

[Condi]

Shirley the obvious thing to do is drop the oil down a bit and see if it keeps doing it.

[Steffan]

Frothing in the crankcase with modern detergent oils is possible with overfilling. But very unlikely as a cause of low oil pressure.

Much more likely that either the pump is on the way out, bearings are in trouble or, just possibly, Oil Pressure valve or sender is suspect.

I regret to confirm that 40 years of car engine fun suggests to me that a flashing Oil Pressure light usually means real trouble.

Any competent garage could check this in minutes. That is what I would suggest.

[james0]

My guess is bearings or oil pump worn or at the very luckiest the oil pressure/level sender is faulty. Driver sees oil light and keeps adding oil, one way or another the engine is going to die unless somebody looks at it soon.
Is it knocking when its warmed up?

ETA:- Beaten to it. Also the oil pressure relief valve could be stuck open. I wouldn't drive it any where until its been looked at properly

Edited by james0 on Tuesday 13th March 23:35

[ShayneJ]

Either or a combination of

pump worn out
gummed or worn out piston rings (is it chucking out blue smoke)
oil pressure relief valve stuck partly open
crank bearings on the ragged edge of being stuffed (is there a heavy knocking sound)
over filled sump causing frothing of oil leading to
air bubbles getting into the pump/oilways.

you said its an inch over the full mark
get him to drain off the extra back to the normal
full level and take it for a run if its still flashing
the oil pressure lamp then its one of the other faults
and potentially major work required.

[johnpeat]

As people have said, the light isn't saying too little oil, it's saying too little pressure - so if the oil is around the right level then it's the pump (or a blockage somewhere - or a faulty sensor) causing the light. I'm pretty sure they won't show 'too much pressure' - that shows by seals being blown open (or worse)

Are you checking it properly tho? Some cars have to be checked when running, others cold and some 'warm' (within a number of mins after turning the car off). My old Vectra was weird - it would show MUCHOS oil when running, none at all when cold and the right amount if you checked when the manual said you should (well, it did when I got the right dipstick for it - it came with one which was far too short!!)

[Caesar9]

I would be checking the sensor and fitting before anything aswell as making sure there's the proper amount of oil in it.
Does it smoke, knock, rattle or sound fine?
I wouldn't be running it to much until you know whats causing it though.

[HustleRussell]

An inch? Surely that is at least two litres overfilled?

[davepoth]

HustleRussell said:

An inch? Surely that is at least two litres overfilled?

Coming on for that I would guess - usually a litre between maximum and minimum I think.

Looking at the Haynes the sender is on the head, which is interesting. That might mean a blockage in an oilway or a stuck oil pressure relief valve.

[Ozzie Osmond]

The oil pump is for pumping oil not for pumping air. If excessively high oil level is causing the crank rotation to dip in and froth it up the oil will be full of air bubbles. This could lead to low oil pressure.

(Compare, spongy brakes if there's air bubbles in the brake fluid)

First step is to get the oil level down to its correct level and leave the car to stand for a while. Then start it up and see if the oil pressure light extinguishes. If not, you'll be needing a trailer - don't drive it.

[monthefish]

doogz said:

Just to add, in my car,

Which one?

[E30M3SE]

BMW E30,

Which oil light is coming on?

The light in the instrument binnacle or the oil level light on the overhead console?

If it's the oil light in the binnacle then that is the pressure light, so he may have low pressure or the switch maybe faulty which is not unheard of.

If it is the level light in the overhead console then that is a low level light, but if it's overfilled then I don't see why that would be coming on.

When is the light coming on, at idle speed, cornering, no real pattern?

Edited by E30M3SE on Wednesday 14th March 10:03