Engine Oil Light ON - help and advice

[Salazar]

Some bad news guys, having sold my 5G today, the buyer called me up later saying the engine oil light started flickering on at low revs/no load a few miles from home, it would then go out again with the throttle applied. No other issues and the car is driving very well.

So I've driven up there this evening to have a look at the problem. The car was started from cold and the oil light didn't come on, but as I suspected the light flickered on dimmly when the car came up to operating temperature and just stayed there flickering. When revved at a stand still and not in gear the light goes out, but then as soon as it returns to idle the light comes back on. For now I've given the buyer the money back, taken the keys and I'm having the car trailered home on Tuesday morning, with a view to fixing the issue so the buyer can have a perfectly working car back again.

My suspicions from the start on this are that it's the oil pump that is failing/failed. The car has only covered 65.6K miles and has only been driven a very short distance with this issue today. There are no nasty noises coming from the engine and she still sounds perfect, so I feel confident no damage has been done. Any other theories on what the issue could be? I dont think its the sensor, as that would mean the light would just be on all the time, and not flicking on and off depending on engine load.

Having looked into it briefly, my question is how easy is it to change out the oil pump and is it an engine out job? Over my 5 years of ownership I've worked extensively on the car, and I've had the crank pulley off in the past, so I have the tool needed for that. I'm hoping that I can change the oil pump by accessing it through the wheel well as with a cambelt change. Anyone have any advice or links to how to's or similar threads?

[Donald]

That is a massive shame. As far as I know its pricey, the pump is an expensive part. Other than that I clearly don't know enough.

[Gayno]

I would say it's possibly just low on oil.

The light indicated low pressure, which would explain why when revved the light goes out, as this is increasing the pressure through faster speed of the oil pump.

Might be worth a check and top up, save you a hefty job that it may not require.

[Donald]

I would've thought the oil level was checked first Big ol runaround if not.

[Salazar]

Thanks for the replies lads. Yeah, I checked the oil level yesterday and it was spot on, the car has only covered about 300miles since the last oil change. The buyer checked it again when he got the car home and put a small amount of oil in to make sure. I understand the light indicates low oil pressure, so that's why I think the pump has failed. The light doesn't come on when the car is started from cold as the oil is thick and creates enough pressure, but once it warms up and thins the pressure drops. As you say Gayno, when the car is revved the oil pump is speeded up and the pressure returns to an acceptable level. I've never had the oil pressure warning light come on in all the time I've had the car, even if the oil has dropped below the max on the dipstick.

I wonder if the oil pump have pressure relief valve for the pump output? I wonder if that could be stuck open?

[jjmartin349571]

Is the car idling at the correct RPM when warm?

[Salazar]

Didn't check the rev counter when the engine was running today, but it sounded like it always does when I was at the engine bay, so I'd say it was running normal. She sounds sweet as a nut, just the light flickering that shows there's an issue.

I've just looked into the pressure release valve on the oil pump, and I think it's accessible by just removing the sump. Replacing that may be my first port of call.

[mercutio]

check the oil pressure sender

[NafemanNathan]

Sorry to here that mate. What a pain in the ass. Good on you for being the decent seller though

As for the problem, it does sound pump related sadly. Before tackling the pump, check the sender (or the pressure from the sender port) as Merc has suggested. If there's still no joy there you could check the oil pick-up pipe by removing the sump first. It could be blocked which would cause your issues. Much easier to check that first.

Can I ask what oil it is/was running?

[Salazar]

It's running Mobil 5w40 fully synth, not sure which Mobil as the details are with the car which I'm not getting back until Tuesday, I think it was called Synth S.