I bought this 2002 A4 Quatro used with 102,000 miles last week. I had to leave it sitting for a week after i drove it for about 300 miles after the purchase. Afterwards when I ran about 10 miles after this week off the yellow oil can symbol appeared in the center instrument console with the word "SENSOR" next to it.

Reading in this and other forums has me scared. I have already collected the timing belt, water pump, etc. to do the timing belt replacement this week since that is about due and now this. I understand the sludge issue and I have no maintenece records fronm the previous owner which gives me an even more sick feeling.

I have the VAG COM cable and program if there is anything usefull I can check there.

I am thinking of pulling the oil pan and cleanng out the sender and screen and also to assess how bad the sludge is if it is there. Then I will do AutoRx afterwards since it takes some time to work its magic and meanwhile the oil pump will not be obstructed, no?

I will also check continuity of the sensor. If it has continuity with the engine off then that is a bad switch, correct?

If this is a sludge issue then there has already been damage done to the engine since oil flow is impaired, no?

i have to drive about 144 miles to get it home to work on. Think I will fry it on my way home? The oil level is topped off BTW.



Crud.

 

If you think is sludge don't ignore the issue, don't drive it and drop the pan to check it out. It is the 1.8 correct?

 

Well I have read further and it seems that the YELOW oil can means there is a problem with the oil LEVEL sensor attached to the bottom of the oil pan. Since I know the oil is full this is a bad sensor or wiring. The RED oil can is an oil PRESSURE indicator which is indicative of failed pump or blocked flow. I do not have the RED oil can.

Do you disagree?

I am still going to do the AutoRx maintenece procedure though since I do not trust the previous owner. It can't hurt, no? What is the deal with AutoRx and synthetic oils? I usually use Mobil 1 synthetic but they say not to use synthetics.

 

Yeah, this is a sensor issue. Still dangerous though bc if something happens and you lose oil you wont have a warning until the pressure warning, and usually by then its too late. So, its up to you if you want to drive it or not (i probably would). You need to replace the sensor soon though...

If you are worried about sludge i would seafoam right away.

 

^^ Agree.. Sensor issue most likely. Drive it home, fix it.

 

I still wouldn't drive it, tow it if possible but that's me.

 

towing? for a LEVEL sensor? You are aware most other cars don't have this warning....including all VWs with the same motor (if it's a 1.8t). Check your oil level daily (human sensor) until you verify that it's faulty and needs replacing. You will also need to change the oil at the same time since it requires a pan drain. Dropping the pan if it's like my 1.8T passat, is a PITA and the subframe has to be moved. I haven't looked at my A4 much since the wife drives it.

 

I just would be afraid of the Sludge, that's why I wouldn't drive it until I drop the pan.

 

Does this light turn on when you need a oil change?

mine did this and i noticed i was pretty low on oil after and added a quart. dip stick says its good but warnings still there.

think i should change the oil filter and sensor and clean oil feed tube?

 

i just changed it last weekend...like 30 some bucks from ecs...I had an intermittent yellow light too for awhile..but I check my oil almost daily so it didn't really matter. If you don't check your oil regularly then change the sensor soon, if you do, then you can wait till your next oil change is due