Hello all,

Just bought a used 2004 A4 two weeks ago (1.8T FWD with CVT) and I have been veryhappy with the car. It had all the scheduled maintenance performed. I had the oil changed with Castrol Synthetic 5W30 8 days ago and it has driven fine, but yesterday the oil pressure warning light starting coming on when I am decelerating. I thought it might be an electrical glitch, but it happened again today.

It only seems to happen after the car has been running for 30+ minutes (so it has been at operating temp for some time) and when I am decelerating by coasting down from 40+ mph (over 2K RPMs) and the RPMs are dropping down just under the 2K range. If I start accelerating again when the warning light comes on, it goes off, or when the car drops down below 10mph, it goes off.

Have any of you seen this before? Is Castrol Synthetic a bad oil to use in this engine? It is strange that it took it a week after the oil change to start doing this, but I have to think it is related since the car never had this issue in the past (the previous owner took it to the dealer for any problem and there is no record of it). Is it possible that the oil is not running back down to the pan from the head as fast as it is being pumped to the head, and therefore over time, the oil in the pan gets low? I suppose that wouldn't explain it because when I accelerate again, the warning goes out.

Thanks,

 

U better check your oil level and the color of oil.
Look under the car onthe ground after the overnight parking for some oil.
I dont think it has anything to do with an oil brand, but who knows.

 

Thanks AudiProtein. I did and the engine is full and the driveway underneath is dry. It is strange that it just started happening 5 days after an oil change. Oil color is normal.

 

Oil pick up tube is probably plugged up.You should replace the tube and perform an engine flush.

 

Thanks AudiTech616. The mechanic did replace the pick-up tube, but it back together, and still had the problem. So they tore it apart again, put a new oil pump in, and idle oil pressure still only at 12psi. However, the pressure at 3000 RPM is about 55psi.

What else could be causing this -- a worn bearing or lifter causing the pressure to leak off?

How do you flush the engine? This mechanic shop doesn't seem to know how to do that.

Thanks,

-Matt

 

UM...............maybe the oil filter? The oil pick up tube was probably indeed plugged up, but the oil filter usually gets clogged right along with it.......thats why it says in the sludge repair to replace just about every oil/PCV line in the car and perform and engine flush after replacing the pick up tube.. Just a suggestion.

 

Read here
post 1
post 2
post 3

I dont wanna scary you, but from those thread you can see that it is not recommended to drive the car if you have an Oil Low Pressure light on.

If you open you engine cap where you put an oil, do u see anything close to this??? http://images.google.com/imgres?imgu...%3Dru%26sa%3DN

 

That last link has nothing to do with oil sludge, thats what happens when you only drive short trips all the time in the winter. It develops moisture in the crankcase and gets white stuff on the oil cap. Almost all the audi's at the audi academy had that under the oil cap because they didn't drive more than 20 feet.

 

Regarding my oil pressure problem, here is the latest. Pickup tube screen had a little sludge, but not enough to stop up the screen or to cause oil pressure drop. Replaced pickup tube and oil pump, but it all back together, and still having the oil pressure issue when coasting/decelerating. At idle, the oil pressure is around 10psi when hot instead of 18psi.

Now the tech thinks he found the issue. He believes I have a vacum leak near the back of the crankcase where some tube has come loose or has broken. Having never worked on an Audi, I don't know if this is real or not. Does this make any sense?

Thanks.

 

How does a vaccum leak cause an oil pressure drop? I couldn't tell you that because it doesn't make sense.
Did he change the oil filter or not?