Big Red Oil Light Warning A4 TDI 1.9. 1999 V Reg.

[Rob69]

you mentioned in post#1 that the oil level is too high, it could be diluted with diesel if it's had a leaking injector, giving low viscosity and low pressure at start up. As far as I remember on those engines there is no other route for diesel to enter the lube oil system other than a dripping injector nozzle, as the injector pipes, leak off system and pump are all external to the engine lube oil system and internals. Does the oil light flicker on when the engine is hot and idling, or does the light stay off after the initial indication? If the light comes on at idle with the engine hot then it could be genuine low oil pressure, caused by low viscosity or mechanical problems. Hopefully your mechanic will change the oil and filter in the first instance as you have no history of a recent change, then see if the oil light situation improves. Best option would be to check oil pressure with a pressure gauge, on cold engine and at full working temp.
I had one of these old 1.9 engines (AGR) and loved it, 75000 miles is nothing on it. I put over 100k on mine with only routine servicing and a replacement MAF sensor and EGR valve. I reckon it was the best, most robust diesel engine I've ever owned, they've gone downhill ever since in terms of reliability and durability IMO !!

[jacksticks]

you mentioned in post#1 that the oil level is too high, it could be diluted with diesel if it's had a leaking injector, giving low viscosity and low pressure at start up. As far as I remember on those engines there is no other route for diesel to enter the lube oil system other than a dripping injector nozzle, as the injector pipes, leak off system and pump are all external to the engine lube oil system and internals. Does the oil light flicker on when the engine is hot and idling, or does the light stay off after the initial indication? If the light comes on at idle with the engine hot then it could be genuine low oil pressure, caused by low viscosity or mechanical problems. Hopefully your mechanic will change the oil and filter in the first instance as you have no history of a recent change, then see if the oil light situation improves. Best option would be to check oil pressure with a pressure gauge, on cold engine and at full working temp.
I had one of these old 1.9 engines (AGR) and loved it, 75000 miles is nothing on it. I put over 100k on mine with only routine servicing and a replacement MAF sensor and EGR valve. I reckon it was the best, most robust diesel engine I've ever owned, they've gone downhill ever since in terms of reliability and durability IMO !!

Cheers Rob ! We have an Audi 80 TDI too, that's done 185000 and still going strong.

The Light and beep comes on with turn of the key - when I press button on dash it says 'stop engine, check oil level' - that's with engine off. Once engine starts the light flashes for a few seconds with no beeps and then doesn't come back on again. Another mate who's a mechanic is convinced it's just because oil/filter hasn't been changed recently. I've managed to track a vagcom engineer down who will hopefully come and scan it to be safe. I think I paid a lot for the car £1600, but it's an SE with full leather. I only paid 550 for the Audi 80 a few years back so can't complain! Thanks again

[Rob69]

OK - hopefully all is ok pressure wise then, sounds like it might be an oil level sensor problem, I'd still consider sticking a pressure gauge on it to confirm though.

[jacksticks]

Quick update. I had someone come and do a vagcom scan. No mention of any thing Oil related. Just coolant temp sensor fault (which I knew about - it gets to 90 then flies back to 0) central locking pump leak, and front speakers intermittent. Got it in for oil and filter change tomorrow am.

Would bad oil pressure be flagged with a scan?

[Rob69]

not if it is a mechanical issue like worn oil pump, bearings or low viscosity, a scan might flag up a sensor fault but maybe not on that year of car. Pressure gauge will be the best way to ensure you have decent pressure.

[jacksticks]

Ok - thought that would be the case. Thanks.

[Rob69]

I should have said though, I think if it was genuine low pressure due to wear or low viscosity, you would see the oil light coming on when the engine was hot and idling, rather than at initial start up. And it sounds like the light is going out more or less as soon as the engine runs. Maybe this beep and flashing light is a low level warning as the DIS indicates and it is a level sensor in the sump playing up, although I thought the low level indicator was a yellow oil can.

[jacksticks]

Ah right, yes. As previously mentioned when you press the left button on dash it says ‘Switch off engine - check oil level’

[jacksticks]

Quick update ! Oil and filter change today, pressure ok. Oil was pretty manky apparently. Oil level light still coming on as before. I'm suspecting the oil level sensor in the sump now. Good thing is the garage were saying how well looked after the car has been over its life.