seem to be loosein coolant

[chug89]

hi I have a 56 plate a3 tdi 170 Quattro the coolant warning keeps coming on if I open the bonnet with the engine running the header tank is empty but if I turn the car off and remove header tank cap the coolant returns to a normal level also there seems to be quite a lot of pressure when I remove the cap

Any help would be much appreciated as it has been to a few local garages n they cant find a leak

cheers

 

[NHN]

Welcome to the site.

It needs putting under pressure to about 1.25-1.5 bar to see where its coming out from, if at all & the way you've explained is normal for all cars when releasing pressure with lid of reservoir, get someone with the right tool to test the system under pressure.

 

[Chillout]

Sounds like you have a air lock have you tried running it with heating on full and the header cap off and check your return line at the top of the header for flow if you are not adding coolant you can't have a leak I would try pinching hoses .

however if you are adding coolant pressure test as above .

 

[chug89]

it has been pressure tested and they found a leak that part has been replaced and had no warning come on for a bit but then after a while started coming on again. It has had a bit of coolant added but not a lot think I will try running it with header cap off thanks

 

[Chillout]

Mine took ages to purge properly a was shi@&ng myself I probably drove for 200 miles the removed the cap when stopped to let air out squeezed hoses ect.

 

[chug89]

hope this works as it has been an on going problem for a while and very frustrating beeping all the time. When I removed the header cap the other day still had a lot of pressure even after being stood for over 12 hours is that normal???

 

[Chillout]

At least if its still under pressure 12 hours later its sort of a pressure test in away