Oil pressure warning light

[flatbum]

The orange oil pressure warning light on my minor has been on constanly for the past week.I have not started the engine since,and as I was going to change the oil and filters anyhow, I decided to do this on Friday.I don't think the oil has been changed for a long time.After changing the oil and filters, the warning light doesn't come on on starting and the pressure goes to 60.Is this good pressure from cold and do I have anything to worry about ?

[gairlochrosie]

Try changing the oil and filter every 3 months...or at least 6 months...regardless to mileage.

[picky]

60 psi when the engine is cold is fine, what is the lowest pressure when the engine is hot??

[flatbum]

Don't know.I am working on my car indoors with the wheels off and it's a bit fumey after a few minutes ! What should the pressure be warmed up ?

[picky]

i would not run the engine for long in an enclosed space! opinions vary but if the pressure drops below 30psi at any point then in my opinion that is a bit too low for comfort. once you have the car back on the road give it a long drive and see how it pans out. Doesnt sound like anything serious, if the oil gets too low in the sump then that can lead to low oil pressure, so maybe that was why the light was coming on before??

[rayofleamington]

the warning light doesn't come on on starting

the light should come on before the engine is running - not quite sure if that's what you meant!

[picky]

good point ray - the light should be on when you turn on the ignition ( as they is no oil pressure when the engine is not turning!!) then it should go out as you turn the key to start the engine. if the light does not come on at all then the light may not be working.

[bmcecosse]

Maybe it was the filter-clogged light that was on ? Oil pressure of 60 psi at cold is fine - almost any engine will do that no matter what condition. It's the hot running pressure that matters, and 10 psi per 10 mph in top gear is a sort of minimum figure, up to the relief valve pressure of 60 psi on an unmolested engine of course.

[Willie]

First find out what, if anything is wrong with the oil pressure light which
should come on as soon as the ignition is turned on, when sorted, if it fails to extinguish with the engine started and your 60 psi showing then change the oil pressure switch (behind the dizzy). It is always worth checkiing the oil pressure relief valve spring which will not effect the
tickover pressure but will effect the maximum pressure if it is not of the correct length.

[flatbum]

The oil pressure light comes on on turning ignition, but after changing the oil and filter goes out as soon as the engine is started.Before it stayed on.My car is a 1970 , 1098 and it doesn,t have the oil filter switch on.I think only the earlier models had this.

[bmcecosse]

Sounds like the light is working as it should - and you have an oil pressure gauge anyway to confirm. Just remains to be seen how it all pans out on the open road.

[flatbum]

Got my moggie running nicely today.The oil pressure was 60 psi cold and went down to just over 40 psi normal running temperature.Is this ok ?

[bmcecosse]

If that's the idling pressure then it's ok - but was the engine truly HOT? The oil only gets hot when the car is being used - it would take a very long time for it to get up to proper running temeperature with just idling. Running pressure is what matters - and 10 psi per 10 mph (in top gear) is good minimum guide. So at 50 mph you should have at least 50 psi - up to the relief valve maximum of course.

[Roni]

As a guide to oil temp, when I run mine, it warms up to operating temp (water) quite quickly - a mile or two. The oil temp at this point is still only just registering on the gauge. It can take over 10 minutes of solid running to get it anywhere near operating temp (95-100°C) depending on the outside temperature.

[flatbum]

The light has started to flicker again.I checked the switch and found that there was oil on it.I wiped the oil off, and the light went off.Could the oil be coming from the switch, and if so would I be better off renewing it ?