Hi,

I recently picked up my 'new' A8 from a dealer last Friday. I'd been for a decent test drive the week before with no problems. Having picked the car up however, 200m down the road, the oil warning came on. I pulled over, turned everything off and tried again, only for the same thing to happen.

I took it back to the garage who checked the oil levels (which were OK) and advised me not to drive too far in it and to call them after I'd checked the oil when I got home, about 30 miles away. When I checked the oil it was well over the top of the dipstick indicator and was totally clear. I checked with the garage and they reckoned thatthe oil was changed 6000 miles ago so they hadn't touched it. I doubt very much whether the oil in there had done 6000 miles and it was just too clean.

My question then is, would overfilling cause the oil warning light to come on? The car's going back to the dealer on Saturday morning and I'm hoping for an easy repair....

Del

 Id bring the car back to the garage and say that you dont want the engine running with that warning light on.

There are a few reasons why the oil light comes on

The oil sensor is a pressure sensor, so

1                  No oil = no pressure

2                  Block in the oil lines and pipes / pickup / in engine itself

3                  Failure of the oil pump

4                  (very common) Faulty oil pressure sensor.

If i were you i wouldnt drive the car till there was either a pressure test done on the oil or the oil pressure sensor was changed.

If the engine is being starved of oil, then perminent damage can be done. Id leave it at the garage and demand a pressure test and or the sensor changed.

 Over pressure wouldnt cause the light to come on. it doesnt do it any good though really. How much is it over the max?

 I would say its too much oil on with the sound of your dipstick which can cause as much damage as starvation from not having enough,if they have serviced or sold it that shouldnt be like that and some checks have obviously gone a miss as all new cars should have fluids checked

 It's got one of the dipsticks with the circular base and ball about 40mm up, and the oil was up to the bottom of the ball. Using the car very little at the moment, but the oil light only seems to come on when braking or cornering.

Hope to get it sorted Saturday am..!!

It's a cracking car but the duff oil pressure has put a bit of a damper on things! :(

Might have the wrong dipstick in there, and the oil level is actually low. Has been known before.

 If its over the top of the second ball or moulding its over filled is it not?

The fact that the oil is totally clear gives me some cause for concern. There's a;lways black oil in every TDI I've changed the oil on, even immediately after filling, running for a few seconds, then checking.

Hi Rusty and all,

I had a look at a sample of the oil last night by dragging some out of the dipstick pipe in a bit of windscreen washer tube! The oil isn't as clear as it first appeared to be on the dipstick, so I now believe that it has been in there a little while at least.

The problem has occured between my test drive and picking the car up, during which time the garage did a fluids check, valet and wash etc.

I'm still pretty convinced that they may have topped up the oil or perhaps disturbed the sensor somehow. Taking the car back tomorrow morning and will post my results as soon as I know what's happening..

 If you can see in the image Del944 the oil should be to the top ball looking thing.

Thanks for all your help. I'm thrashing a Fiesta 1.25 loan car to death while the garage gets delivery of a new oil sensor which should be coming today (Monday).

Hopefully that'll fix the problem.

Anyone know if overfilling can kill the sensor??

Thanks for all your help guys..

Had a call from the garage after they'd changed the sensor to say the oil pressure still wasn't quite what it should be so they'd ordered a new oil pump and strainer. I did query how bad the pressure was and they said it wasn't awful but not what Audi would recommend.

Got the car back last Wednesday with a new sensor, new oil pump, new strainer, new filter and new oil, and it all seems fine. Had a low oil light on Saturday so checked the levels and added a bit and it's been OK since. I suppose they'd rather underfill slightly than overfill again!

Thanks again for your help and suggestions.