Technical Oil light on at idle

[benoliver999]

The oil light comes on when the engine is at idle.

As soon as I give it even a tiny amount of revs it turns off.

It's definitely happening when the engine is warm, not sure about when from cold.

Oil level seems to stay OK the times I've checked but I'm keeping an eye on it.

Any ideas on what could be causing this?

 

[koalar]

Anything changed on the recently car, oil filter
Did it start after a minor bump

Lots of things I could be, from a faulty switch, damaged pickup pipe and so on

Inspect the sump with a torch for dints, fairly common

Look at the oil switch for leaks

Without putting a pressure gauge on it we are guessing really

 

[benoliver999]

Garage put a new oil filter on it at service, otherwise I'm not sure when it started I've not had the car that long.

Thanks though I'll start looking where you suggested

 

[koalar]

How long have you had the car
How long since the service

Check it's not leaking from the filter


There were two filters fitted, early cars had a long filter, later cars like you're a short filter

74mm Vs 90mm approx there may be a small variation with different manufacturers

 

[benoliver999]

Had the car a couple of months, service was about 6 weeks ago.

 

[koalar]

Unlikely to be connected, I would think

If you can't see any leaks around the oil filter, oil switch or dints in the bottom of the sump

Then fingers crossed it's just a dodgy switch
Similar to this https://www.fiatforum.com/threads/low-oil-pressure-light-at-low-revs.341612/

Bought privately or from a garage, bought trade they should sort it out for you

If a private sale, throwing a new switch (£5) would confirm if it's a faulty switch (farly likely) or a genuine fault and still cheaper than buying an oil pressure gauge

 

[benoliver999]

I think we might have found the culprit. Slightly porous sump. Had a new one fitted, we'll see what happens on the next long trip.

 

[DaveMcT]

New sump costs under £30 plus a tube of silicone. Just change it.

 

[benoliver999]

Sadly can't do it roadside, I've got nowhere to do it where I live! Plus I hate working under the car on axle stands.

Quotes for getting the work done at a garage ranged from £140 to £450! (I got it done, I should add)

 

[koalar]

Do we still have the oil light on

Weeping sump will not cause the oil light on at idle

A damage sump will but will require a new pickup pipe

 

[benoliver999]

It will be a while before I find out, the light only comes on after a long ish trip at motorway speeds, and only at idle.

 

[koalar]

It will be a while before I find out, the light only comes on after a long ish trip at motorway speeds, and only at idle.

Oil light only comes on at very low pressures

We need to try and diagnose this before the sump is changed

It would be silly to change the sump only to have to take it off again, to replace say the pick up pipe

Is there any sign of damage to the underside

 

[benoliver999]

Sump already replaced, I did ask about damage, they didn't see any.

I've not seen the light in quite some time, it's only when the weeping sump came up at MOT that I remembered this thread.

I'll check around the switch and try a new one. I also know someone who can come do a pressure test.