so i'm new to the audi world..recently bought an 2001.5 s4. car has 79k miles on it and there were some problems. took the motor out and replaced both turbos, passenger side egt sensor, timing belt and all that, spark plugs, front axles, front and rear rotors/pads..downpipes and test pipes with an APR tune...drove it a few days ago for the first time, and the light for low oil pressure shows up and every once in a while there is a really bad squealing noise which seems to be coming from the front (sound like the front right). i just replaced the oil pump and the screen had a lot of crap in it. thought that might be the answer, but no..still getting the low pressure light, and also the noise, and not sure if they are even related...oil level is fine and i can't seem to figure out what the heck is going on. can anyone point me in the right direction? thanks

 

probably a bad oil pressure sensor. $8.50 from jhmotorsports.

loud squealing noise? could be anything. almost impossible to diagnose via internet with the information you have provided. have you scanned for codes? (not that squealing noises throw codes but it would be something). see if you can narrow it down a bit for us

also, Wilkommen to the forums

enjoy your stay

good luck

 

i picked up the sensor this morning just in case and just replaced it and going to take it for a short drive soon....the squealing...it almost sounds like a brake squeal....only it lasts a little longer and my foot is not on the brake when it happens. no codes are coming up with a basic code scanner...i do not have the vagcom thing, and havent even researched enough to see what a vagcom can do..and just to make sure it wasn't a seized caliper, i just took them off and they are also fine...

i'm itching to drive this car again...i have only driven it 3 times in 3 weeks, once being the night i got it,...but i love this thing already and have always wanted one...

 

ok...so it is not the sensor either...still have the crazy and scary noise...and the light it still coming on.........

 

did you replace your serpentine belt? re-use any metal gaskets?

 

nope...everything i touched was replaced with brand new..turbo gaskets..serp belt..t-stat..valve cover gasketst...i'm stumped on this one...with the new oil pump and sensor, it would almost make me think main/rod bearings as i've had that in my jeep....i can do that work, just don't feel like pulling the motor again....i'm still hoping it is something else...it also doesn't seem to be doing it at higher rpm's...i've heard it around 1800 and 2800rpm for sure, the exhaust is a little louder at higher rpms to heard the noise at speed...

 

oil line problem to one of the turbos? maybe?

at this point i'm just swagging away.

 

on the oil pump, there is a metal hose that goes from the pump to the engine block...should there be rubber o-rings on both ends of that?...and where the pump feeds oil into the motor, should there be some kind of gasket on that? or is it just bare metal right to the block?

i put a cheap mechanical gauge on where the sensor goes, and there i basically no pressure at idle...and at 2000rpm's, it was about 25ish..don't know how accurate the gauge is though

 

O-rings on both ends of both those pipes and no gasket where it bolts to the motor.
Hope it isnt hurt already.

 

thanks...i posted this over on audiworld as well and got it figured out..i ended up replacing the main and rod bearings...now all is well and i get to drive it...hopefully it stays this way...