I am a GM guy working on an 2002 a4 avant, 1.8l , auto trans, for a friend. I have no experience with audi's, besides doing a little research the last several days. So I am a little ignorant to their problems or specific engine components. The problem started several months ago. Immediately after an oil change(audi filter with non synthetic 5w-20), driving on the freeway, he first had two hoses blow off on the left side of the motor under the intake causing oil to spray out(his mechanic called them vaccum lines. But what vaccum lines under the intake are full of oil??!!). He noticed smoke from the burning oil and the oil pressure lamp flashed. He took it to a mechanic who repaired the hoses and swapped out the oil and filter with unknown parts. He told him his hydraulic tensioner was failing and may completely fail at any time. He tried driving it one other time since and said his low oil pressure lamp came on and he heard noise from the engine. He said the mechanic couldn't explain to him the cause of the problems so he lost confidence in him. Thats where I came in. After a little research, I learned of the 1.8l engine sludging issues and related problems. I checked out the motor the other day- its starts and runs fine oil level is clean and full and no lights came on. I took it for a drive and after approx 30 minutes of run time, the oil pressure lamp started flashing and what sounded like upper engine noise,suspected lifter noise occurred. so I removed the valve cover and visually inspected- the top end looked rather clean, no signs of sludge or deposits found. I removed a majority of the cam caps and they all look good. I suspect the noise is either coming from lifters after oil pressure drops, or the electronically controlled cam tensioner is failing. Without any knowledge of description and operation on the (cam chain tensioner)setup, I can only guess the tensioner is responsible for the chain that drives the oil pump off the cams(am I wrong)? I told my buddy to do an oil change with audi's recommended oil and oil filter prior to going any further, to eliminate any issues. Before I go any further and start replaceing parts and or tearing down the engine I would like to get as much info as possible. If anyone has any idea of what the problem maybe or how this system operates, any information would be greatly appreciated. Ive done a forum search and have not found any info on how the chain tensioner operates and how it relates to low oil pressure and why it makes noise. Also Im am a little hesitant to believe the issue is caused by oil sludge blocking the pick tube, due to how clean the top end is, and how everything is fine until it warms up(you would think a blockage, or a bad oil pump would cause it to occur all the time).
Also when I hear of vaccum lines blowing off I think of turbo(high manifold pressure issues); when I hear oil lines blowin off I think PCV restriction; anyone experience this or know what hoses these were that blew off?? I didn't look too close. Thanks for any advice.

 

I know the length of my original post might scare off most readers. So to cut to the chase, if anyone could direct me to more information on what type oil pump is used and more info on the electronically controlled cam chain tensioner and its problems, would be a great help. thanks.

 

Well the PCV system is clogged all to hell, which caused the oil pressure problems. There is a world wide TSB for any 1.8T that will cover the repair whether it be a repair or engine replacement free of charge as long as the owner can show oil change reciepts of at least every 10k. The problem isn't the oil pump, nor sludge, its crap built up in the oil pick up screen. If you want to fix the car yourself, drop the pan, change the pick up tube, replace any affected PCV hoses/valve, change the oil and filter. Eventually after the repair the cam adjuster should stop making noise (sounds like a diesel), if it doesn't you will have to replace the cam tensioner (back of the cylinder head) Its a $600 part though.

 

https://www.audiforums.com/forum/sho...t=facts+sludge

Here is a thread i made about the issue long ago.

 

so the cam tensioner is fed oil, and making noise due to lack of pressure? What does the back of the engine cam chain drive and whats making noise(chain guides does not appear to have any damage)? still unclear.... the mechanic told him the tensioner was setting codes. And have you seen a plugged pickup screen cause intermittent issues, only when hot? Have you seen the lifters fail on these?