Hi,

I have the red oil pressure light coming on with a ding on my 2002 A4 B6 1.8T. When the oil pressure light comes on the tappets get noisy, so I do believe the warning. Here's my troubleshooting so far:
1) I ran engine cleaner through the vehicle, and added new oil and filter. It ran fine for 30 Kms then flash/ding again.
2) I have replaced the oil pump and pickup, new oil and filter. Tested with a pressure meter at cold and pressure is fine. It ran fine for 30 Kms then flash/ding. Please note that the oil pressure was not retested at this point with the light flashing (the mechanic messed up here, hey?).
3) More engine cleaner, new filter, new oil. It ran fine for 30 Kms then flash/ding. (I heard that it could need a second dose the clear any sludge).
4) Here's the interesting thing.... I took a couple of litres of oil out of the sump and poured it back into the top. It ran fine for 30 kms then flash/ding. Another 2 litres out of the bottom and into the top and the same thing - I get 30 kms out of it and then the oil pressure light comes on and the tappets go noisy.

Please.... does anyone have any idea what this could be? Please note that when I say 30 kms I am not saying 15 minutes... it doesn't matter if I leave it overnight.... it's around 30 kms of engine running time.

This has completely baffled me and every mechanic that I've spoken to. We've changed the pump/pickup/oil/filter/desludged... and yet it's fine for 30kms when oil is poured into the top.

 

id recomemend you ask your mechanic what the oil pressure is at when you run the oil through the top and when the pressure is at when the oil light comes on. What oil are you using and a possible suggestion is run a thicker oil like rottlea 10w-40