Flickering oil light when hot.

For the past year or so my 90 has decided to pop the oil warning light on when its really warm, ie off roading and had some hammer.

I thought that this was due to the engine that was in it having either a slipped cam bearing or worn piston rings (used to blow a lot through the cyclone breather which is routed to atmosphere)

I changed the oil pressure gauge and it carried on so I rebuilt a total different known working engine. The only thing I used off my existing engine was the head.

And so it happened again however engine runs sweet fires up straight away ect. I used a real thin oil to start with I think it was 5 30 fully synthetic. It happened again however I had now fitted an oil pressure gauge which shows around 15-20psi when the light comes on. So I've changed the pressure switch again and also put some 20 50 oil in to see if that helps but that's the same. Could it be faulty wiring or am I missing something simple

IamRobbie said:

For the past year or so my 90 has decided to pop the oil warning light on when its really warm, ie off roading and had some hammer.

I thought that this was due to the engine that was in it having either a slipped cam bearing or worn piston rings (used to blow a lot through the cyclone breather which is routed to atmosphere)

I changed the oil pressure gauge and it carried on so I rebuilt a total different known working engine. The only thing I used off my existing engine was the head.

And so it happened again however engine runs sweet fires up straight away ect. I used a real thin oil to start with I think it was 5 30 fully synthetic. It happened again however I had now fitted an oil pressure gauge which shows around 15-20psi when the light comes on. So I've changed the pressure switch again and also put some 20 50 oil in to see if that helps but that's the same. Could it be faulty wiring or am I missing something simple

Click to expand...

light shouldnt come on with 15 - 20psi, presumably thats at idle

jamesmartin said:

light shouldnt come on with 15 - 20psi, presumably thats at idle

Click to expand...

Yes at idle. Oil level correct so I can't fathum why the pressure would be so low.

Ooo just noticed you said shouldn't... No idea why it does come on but it's annoying as hell. Could it be the solenoid? Running out of ideas

Iirc oil lights tend to come on a seriously low pressure something like 5 psi and by then its normally to late, so they are not really much use!

I don't like the thought of disconnecting it however its getting annoying especially when I can see that the oil pressure is around 15psi

Oil pressure relief valve? I had similar problems so dropped the sump and fitted a new one with new spring with new sump gasket never had a problem since

+ 1 on above.

IamRobbie said:

Yes at idle. Oil level correct so I can't fathum why the pressure would be so low.

Click to expand...

does it raise to 50 psi when you raise the revs

yes around 40-50 psi it does when driving, the oil light will go off if I just rest my foot on tickover so its only just on, it flickers on and off when hot and when its had a real good thrash up a decent hill it may stay on when really hot however the electric fan doesn't need kick in often at all and that's on a sensor on the bottom of the rad so the rads cooling the coolant enough just not sure why the oil lights coming on