Rampdog

I have a 1.8T Quattro, recently I noticed a noise under the hood which I believe was the rear bearing in the alternator. But then I also noticed right away after that the oil temp goes up to 250 or more where it never went past around 220 in the past. I use Mobil 1 oil and 0-40 weight. Also I have been noticing a hiss when getting on the turbo, which was replaced about 20,000 miles ago. I also have a bit of an exhaust smell to my oil... What could be happening here. I hate the Audi Dealer near me, they always want me to replace everything but the kitchen sink when I go there.

Pete@ECSTuning

When the brushed begin to fail in your alternator is will sound much like a bad bearing in the alternator. Either way it would need service. If it is the brushes you may be able to escape by just replacing those. If it is the bearing, I'm afraid you may be looking at a new alternator.

As per your oil temp issue: The oil temp sensor could be faulty or you may be running hotter. Have you changed oil weights/types or is the ambient temp increasing where you are? Your oil is also cooled by an oil cooler feeding of your radiator. How is your coolant level? How long has it been since a coolant flush?

Rampdog

I have recently done both the flush and replacement of the fluid, and also the temp sender unit behind the block. I had a VAG error code of 17544 which has something to do with the mixture being lean, does this sound like it could be a vacum leak? Potentially a injector O-ring where the air gets in and then the ECM adjusts the mixture by dumping fuel in?

Rampdog

As far as oil goes I have not changed anything, run mobil 1 constantly. 0-40 which is the weight suggested by AUDI.

Pete@ECSTuning

"Long Term Fuel Trim Add.Fuel,Bank1 System too Lean"

This could be a host of issues: Fuel pump, fuel filter, clogged injectors, poorly seated injectors, just what I can think of off the top of my head.

How long since you've changed your fuel filter? Also run an O2 sensor rediness test.

juttin

I had that noise when my water pump went. Maybe that's that's screwd up

Pete@ECSTuning

Huh, that would make all sorts of sense. Broken plastic impeller causing poor water circulation equating to higher oil temps and an odd rotational noise. A great theory! OP: How long has it been since you've done a timing belt?

Rampdog

Well I took it in to a local shop they put a stethascope on the belt tensioner and the alternator, the alternator is where the noise is coming from. I did a compression check all at 120 so that seems ok, one thing I noticed was that the tester end was getting oily residue from inside the motor, so I took apart the intake plumbing and found about 3 oz of oil in the intercooler and the cross pipe that goes under the radiator. apparently this oil was getting sucked thru the car... seems to me it can only come from the TURBO which I had replaced about 20,000 miles ago. Now I can imagine a bit of oil over time, but this seemed like too much. seems like this could screw up the mixture as well. I am going to pull apart the Throttle body and make sure its clean and throw it back together. Can it be a seal in the turbo gone bad? I know it still spins and pumps, can it be serviced?

Pete@ECSTuning

Are your coil packs oily? Might have a valve cover gasket issue if that tool was getting oily. That is a very easy fix. As per oil in the intake it could be a turbo issue or the crankcase breather issue. 3 oz of oil seems like a lot for 20k miles. Unless you didn't clean that before the new turbo?

Rampdog

I have done a compression test recently and they were all at right around 120, I read that's low... if that is the case and they are all the same could it be a head gasket issue? IT doesn't leak anything (imagine that), nor is there any water in the oil or vise versa... Going to buy a PCV valve and flush the coolant system this week to see what that does. I have not been driving this car because I don't like the oil heating up, but I need to get it fixed and the local AUDI shop is CRAZY for labor prices to even diagnose the thing...