Oil pressure light

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JohnH
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Wed Apr 18, 2007 10:24 am

Hi,
I changed the oil and filter in the iS on Sunday. I used Silkolene Pro S 5w40 which I bought from Opie Oils.

Once I started it up again afterwards the oil pressure light flicked on for a second but went out straight away. I let it run and took it for a bit of for a bit of a drive with no problems at all, in fact the engine sounded much quieter.

I didn't use it at all yesterday or Monday so this morning I drove it to work. The oil pressure light flicked a bit initially and I thought it was going to go out like it did on Sunday but it came on permanently and stayed on the whole way (10 miles).

When I got to work I checked the oil level and it looks fine —a though the warm oil was very thin in comparison the old gunk that came out on Sunday.

I'm not too keen to keep driving it with the oil pressure light on. Has anyone got an idea what might be causing this, or if it's serious?
Thanks
John
Templ8e30
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Wed Apr 18, 2007 12:23 pm

The new oil is thinner and therefore a little will drain back into the sump when you leave it turned off for a while.

The light flickering at start-up is nothing to worry about, just the oil pump re-pressurising the system.

Cheers,

Iain T
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billgatese30
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Wed Apr 18, 2007 12:25 pm

before you try anything get a new oil pressure sensor (don't take your e30 though in case it is a genuine case of low pressure)

the fact that you've driven it for 10 miles with (what appears) to be no pressure makes me think that there is oil pressure there somwhere otherwise i would have thought it would have seased up beofre now.

try a new oil pressure sensor and see what happens, but i wouldn't drive it untill i have tried this
Templ8e30
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Wed Apr 18, 2007 12:52 pm

Just re-read the post properly, definately don't drive it with the oil light on !

Could be a worn oil pump if it's not the sensor.

Cheers,

Iain T
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Brianmoooore
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Wed Apr 18, 2007 1:43 pm

Bit late for you now, but oil pressure light at anything above idle means kill the engine NOW. Not in ten miles time, not at the next layby, but NOW. Gear lever into neutral, ignition key off and coast to a halt, unless doing so would be dangerous.
I take it the light is now permanently on? Even from cold?
If so, the first thing to do is to pull the connector of the oil pressure switch to see if this makes the light go out (ignition on, engine off).
If the light doesn't go out, then you have a wiring fault.
If the light does go out, then try a different oil pressure switch before running the engine again.
Oil pressure switch from most BMWs will fit.
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JohnH
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Wed Apr 18, 2007 2:12 pm

Thanks for all the replies lads.
Here's the strange part. I went out the car at luch there. Firstly looked under the car for evidence of a leak, of which there's none,so no worry there. Then checked the level, again no problem.
So I started it up and the light was off? I left it idle and the light stayed off so I took it for a drive around the block and all seems fine.
After Brian's post and looking back over some old posts I'm beginning to suspect the switch might be the problem.
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datonyb
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Wed Apr 18, 2007 7:52 pm

or a short/ bare wire

brushing against the car body or block

had this once scared the living crap out of me

turned out to be the wire earthing
ex 325i came saw done the trackday!
then sold after 4hrs with a sign in the window
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Brianmoooore
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Wed Apr 18, 2007 8:03 pm

Oil pressure switch wire on an iS doesn't pass through quite such hostile territory as it does on a 325, so not quite so likely.
oze30
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Wed Apr 18, 2007 8:08 pm

What about on an m30b35?? i have the same problem (but its the oil light on th echeck panel) .. but it's a 3.5 and I have checked everything.. just can't figure out which sensor is the pressure one?

is it the one at the back of the head? I've unplugged the oil level sensor and shorted it, and no difference.
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Wed Apr 18, 2007 8:12 pm

Brianmoooore wrote:Bit late for you now, but oil pressure light at anything above idle means kill the engine NOW. Not in ten miles time, not at the next layby, but NOW. Gear lever into neutral, ignition key off and coast to a halt, unless doing so would be dangerous.
I'll second that....

I lost my fantastic, sexy little A4 1.8T, due to oil pressure... on the A30 to Cornwall... would never dare drive a car again if the oil light comes on...
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dazleeds
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Wed Apr 18, 2007 8:14 pm

i have a prob with my check panel light coming on randomly also the coolant leve does same
but i put this down to sensors as the dash oil light has never come on when it shouldnt :cool:
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oze30
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Wed Apr 18, 2007 8:23 pm

dazleeds wrote:i have a prob with my check panel light coming on randomly also the coolant leve does same
but i put this down to sensors as the dash oil light has never come on when it shouldnt :cool:
Same.. but its p!ssing me off everytime I start the car and the light flashes!!
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