Alright I'm new to this but here I go, I have a 99 Audi A4 2.8 30valve Quattro last week I started to lose coolant the car has never over heated on me, the funny thing is tho when I placed more coolant in the car it held it for awhile before it lost it again, at first I could find any leaks or anything but today I finally found one. It's on the drivers side towards the rear of the motor, I was able to catch it on video, could it be bad coolant line, maybe a whole in the reservoir? This is all after it's been running when it's cold it doesn't leak but it doesn't do it all the time so I'm having a hard time believing it has anything to do with the block or headgasket, I also don't have coolant in my oil or vice versa and the car doesn't white smoke out of the exhaust

 

It's known that the reservoirs can crack from age and heat cycles. It could also be from a loose sensor connector on the bottom. I would replace the reservoir and see if it goes away. You can upgrade to the white S4 tank for about $25 and it looks way better in the bat as well.

 

All of a sudden my car was at high temp on the display. Opened up the hood and it was pretty much dry. Bought $20 worth of anti-freeze, 5 litres I believe, the tank took it all and off I went. Checked it an hour later in my driveway and it was empty again. Anyone know if I have an easy fix here or am I screwed? Appreciate the help gents.