This is probably a valve cover gasket in need of replacement.

 

I have a 03 A4 1.8 as well with all the issues above, oil in plugs and oil sensor light. Taking it to mechanic on 12/30, i will follow up with a post. Is this common for the A4 1.8?

 

I am wondering if everyone that is contributing to this thread is talking about the same problem.

The initiator of this thread is concerned with the yellow oil sensor light, not the red oil pressure light, right? I believe the oil sensor light indicates a malfunction in the sensor that tracks temperature and the level of the oil. Can anyone correct me on this?

I have an intermittent yellow oil sensor light that illuminates. When it goes on, my oil temperature gauge drops but when the sensor light goes off, the temp needle goes back up to normal.

I believe that either I have a faulty sensor or a short in the wiring...

 

I had the same problem last winter with my 02 1.8T.

Basically the YELLOW oil light that says sensor on the bottom is the sensor on the front bottom of the oil pan that (correct me if im wrong) measures the oil level only.

the YELLOW oil light that says "min" is when the oil level sensor realizes that the oil in the pan is getting too low.

Now, most importantly, the RED oil light means your oil pressure is too low. TURN YOUR CAR OFF AND HAVE IT TOWED IMMEDIATLY. 9/10 times your oil pick up tube is clogged whether its sludge, dirt/grime, etc.. DO NOT drive your car with RED OIL LIGHT flashing!! I did for a total of 20 miles and it cost me a turbo, and this was when the car had about 145k on her.

 

On my Audi S4 2001 I have gotten the yellow oil can periodic warning signal. I put oil in even though it did not appear to be low ( should have trusted that the sensor was wrong) had the oil changed after realizing that some oil got into the coolant and a cloud of white smoke came out the exhaust. Both oil change and radiator flush was preformed. The error codes for O2 sensors and the oil level/temp codes also battery error code. The battery had been replaced last year. I think it was an electrical problem as the warning signal for head lights and tail lights went off . They however were on and fine. The head lights were slightly less bright but still working. I am trying to extend the life on the S4 that only has 62,000 miles so I can buy a new car thoughtfully. I am having the O2 sensors replaced. Is there any other concerns that I should have regarding the O2 sensors? I believe the yellow oil can sensor is electrical. There was never an increase in the temperature nor reduction of oil.