(T) Cinquecento Oil pressure warning

Hi everyone, my first post in this great forum

Not sure if there is a similar post, but on my Cinquecento Sporting I am currently having the oil pressure warning led coming on after about 10-15 minutes of driving, but only when the car is almost idle

In other words, you drive for 10-15 minutes without problems, then after that, each time you idle the car, as soon as it reaches very low revs the oil pressure warning led starts flickering and then goes off when the car is completely idle. This repeats itself until the end of the journey

Any ideas?

Thanks

checked the oil level?
may be the pump is worn and not moving enough oil at low revs

Does sound like a level issue, either that or its not returning quick enough.

Check the level and report back.

Cheers

D

Could be like treacle, when was the oil last changed?

Liam

Do check the oil level.

But what mileage is the engine? What oil are you using?

Often a worn oil pump is accompanied by general engine wear.

It sounds like engine wear, but I don't think you need to do anything about it.

Oil pressure is lowest when the oil is hot and the revs are low, so low oil pressure will always first show under those conditions.

The slower the engine is going, the less oil pumped by the pump. The hotter the oil, the thinner it is, so the lower the pressure.

It could be a faulty oil pressure switch. Not likely, but worth checking as it is cheap.

It could also be a worn oil pump or a faulty oil pressure relief valve. Either could be leaking oil (internally inside the pump or back to the sump) which would lower the oil pressure.

It could be the oil is the wrong type, or not getting enough cooling. I don't think that your car has an oil cooler, so it can't go wrong, so the problem isn't likely to be the oil getting too hot.

However, it is likely to be wear on the main bearings and big end bearings. That makes the gaps too big and the oil can run back to the sump too easily, giving low oil pressure. Regrinding the crankshaft and new main an big end bearings is the only fix.

I would change the oil to make sure it is the right grade and new. I would also fit an oil pressure guage. I would then live with it because the low oil pressure will mainly affect the big end and main bearings, and if they are worn, you can't make things worse. Engines really don't need much oil pressure at tickover to work fine.

With the engine hot, you should expect about 20 psi on tickover, rising to about 60 - 100 psi at about 2500 rpm. The oil pressure shouldn't get much higher because the pressure relief will open and limit the pressure.

With the engine cold, the pressure will be a lot higher at tickover. The pressure may go on rising after the pressure relief is open, because the oil is too thick to get thorough the relief easily.

Thanks to all for your very insightful replies

Although the car was serviced very recently, just a month ago or so, I agree that it is worth doing some basic checks as you say - levels, type of oil, etc.

Thanks again