Using coolant but no leaks !!!!
 

Hi guys,

This is my first post so thanks in advance for any suggestions.
I have an 2.0 TDi Audi A4 S Line (2008) 57 reg, 60k miles. When on holiday in Cornwall in August the coolant level light came on. I topped it up and thought no more of it. Over the past 2 months I must have put about 10 litres of coolant in it. I finally bit the bullet and took it to a garage expecting a huge bill.
The garage has checked the oil, not milky. Checked the exhaust, no white smoke. Pressure tested the radiator whilst running and not running, no pressure drop. Pressure tested the entire system, no pressure drop. Checked the oil cooler as a last resort, again, nothing. They have taken all the covers off, checked for visible leaks and steam, found nothing! They have ran the engine up to operating temperature ~90 deg C and parked it over night over a clean cloth. No puddles in the morning !?!? The only suggestion was to do the timing belt and water pump given its mileage but the guys says he doesn't want to take money off me until he can see a visible leak.
Has anyone come across this before or have any ideas?

Thanks in advance.

Anyone?

I Have a4 1.8T 2006. I have had the same problem with my car, since I bought it on january 2012 but it has got worse. I now think I know where the leak is and I just received a spare part (6 euros) but I couldn't fit it. But the leak is in the black steel pipe connected to the cylinder cover(the pipe is under the plastic cover) . In the middle of the steelpipe there is /is supposed to be a screw that (if i have understood correctly) passes air through but in my case it passes coolant through and it evaporates since the steel pipe is veery hot.

the coolant flange is a common culprit for a no visible leak coolant problem.