I'm having a bit of an issue with my brothers 2001 1.8T A4.
Whilst driving at a steady speed on the motorway his oil warning light came on. He stopped immediately and checked the oil level which appeared ok. He let the car cool for 30 mins and then bravely! started it up and re-continued his journey, the oil remained off for a further 30 mins and then came on again. He pulled off the motorway and into a service station and as he was slowing to stop the engine stalled and cut out. The oil level was rechecked and again looked ok which would suggest a sludge issue resulting in oil starvation.
The car was dropped at my house by the recovery vehicle and I immediately pulled the engine for inspection. When stripping down I found all timing marks were where they should be. The sump was very sludgy and all 8 exhaust valves were bent.
I replaced the valves and did the big end bearings while the block was on the stand. There was no visible signs of bore or cam lobe wear therefore I left alone.
The engine was refitted and timed up with a new belt tensioner and damper.
When starting for the first time the starter appeared not to turn the engine properly (see video link below), which suggested there was an issue with the starter however I have removed and tested the unit and it was fine. I did notice once the starter was out that there appeared to be a score mark on the flywheel and the sandwich plate between the box and block appeared to be touching the fly?? I refitted the starter and slackened the gearbox bolts in case the box and block were not seated correctly but no difference was seen.
I have checked the starter voltage when turning and it's fine at 12v, I have also earthed the negative terminal to the chassis using a jump lead in case of a bad earth but no change.
I removed the plugs and turned the engine over by hand at first and it seemed ok to turn until it got to TDC when it tightened up and then after TDC was easier, which I would assume is normal. I turned the motor over on the starter without the plugs fitted and the turnover is still not right suggesting lack of compression?!?
I removed the cam cover to check the cam timing marks had 16 rollers between and noted that I had only 15.
Is it possible that the initial problem that bent the valves in the first place was the low oil pressure causing the cam chain tensioner to fail and thus bending the valves? I'm concerned that the new valves I have fitted now also bent as the cam timing is out?!?
VID00012-20110205-1132.mp4 video by kaiser_solsay - Photobucket