Coolant loss - can see drips underneath expansion tank

[Tommmygunnn]

Hi all,


I have been getting coolant loss for a while now. It only became apparent a few months ago after a long road trip from York to Madrid! Covered about 1800 miles in about 10 days. When I got back, I took the car for some diagnostics (unrelated but engine management light came on, on the way back), the mechanic mentioned my coolant was low so they topped it up for me.

I didn't think much of it at the time, thought it may be normal due to the massive amount of miles driven in such a short amount of time. Anyway, 4 weeks after that I went to top up my screen wash, and noticed the coolant was around the minimum level. Not knowing how much they topped it up, I topped it up myself. 4 weeks later it was back at minimum.

After the car has been running, I can just about see some splash marks underneath the coolant tank (i havent seen it physically drip from the tank). I hope this is the only source of leak, and not something major like the head etc. Could this be the actual tank that needs replacing, or is there a hose coming from it that is suspect to leaking.

If the tank, how easy is it to replace?

Thanks in advance

 

[Charlie Farley]

what engine do you have fitted.

 

[Tommmygunnn]

what engine do you have fitted.

Its the 2.0 tdi 170

 

[Charlie Farley]

ok, the expansion tanks are known to split and leak , have you check all round the tank for any signs of a small leakage .

 

[Tommmygunnn]

ok, the expansion tanks are known to split and leak , have you check all round the tank for any signs of a small leakage .

I've had a look around and cant see see any signs of a leak but with it being quite difficult to see the underside I couldn't be completely sure. I guess I could stick some white paper / bog roll underneath when I get home next and check 10/15mins later to see of any marks and should give a good indication where the leaks may be coming from if it is the tank.

 

[Charlie Farley]

why not remove the securing screw and lift the tank upwards and out of its mounting bracket, that way you be able to see the whole tank, top ,bottom and sides....you can then be sure one way or the other if that is the culprit..

 

[Tommmygunnn]

I managed to check the expansion tank just now and it appears to be fine with no signs of a leak. I have checked the two hoses/clamps attached to the tank and they seem good with no cracks or visible leaks.

Im wondering if maybe im losing coolant from the heater matrix? I get lots of condensation issues. I have unblocked the drain holes under the battery which improved the problem but hasnt totally fixed it. I also get instant condensation if I have the ECON setting turned on the heaters, I don't seem to get a wet foot-well, but if its only a slow leak, then it may be quite difficult to notice. The car never smells of coolant though, and it goes down from max - min within about 4-6 weeks.

Any guidance or things I could check before taking it to Audi?

 

[Dan burns]

if you have it topped up to the max line then once the engine warms up and you are driving around the coolant rises and will spit it out. if the engine is cold the coolant should be right on the min line as when warm it will rise to the max line,too much coolant and it will spit it out