Andrew T

I don’t think the garage carried out a pressure test after the new cap and bottle were fitted. The heater matrix can get blocked which reduces flow around the system and this produces back pressure which can cause coolant to leak out of the expansion bottle cap apparently.

HI Gareth Yhe car was put in for a pressure test, but they could make a decent seal to get this done. I changed the expansion bottle and cap with Audi parts and the problem is still there. On another forum, a few people are saying heater matrix could be the problem? Im trying to book it in with an Independent Audi specialist , would you have any recommendations? I’ve been speaking to R Tek in Swansea.

I’ve been told by the garage they’ve checked for an airlock and there isn’t one.

I have an Audi A3 2.0tdi 2014 that has a very frustrating problem. The car is leaking coolant when on a run, the coolant is coming from the expansion cap and seems to be caused by back pressure building up in the coolant system. The temperature gauge does not move above the normal running temperature though and I have had no problems with overheating I have also noticed that the cabin heater blowers are not as hot as they used to be and that the passenger side is cooler than the drivers side. The car has had the expansion bottle and cap changed, the heater matrix pipes are both hot and the garage checked for combustion gasses in the coolant but could not find anything, so hopefully the head gasket is ok? Has anyone had this issue and managed to find out the cause please, as I am rapidly getting very frustrated that no one can locate the problem?