Hi, I have a problem with my A7 2013 3.0 diesel, the car has recently started to use water, roughly 2 litres every 1500 miles or so. there are no visible leaks, and the water level often remains static for quite a while before suddenly dropping. my mechanic cannot find any visible leaks, and is saying that he may need to start stripping down between the Vee of the engine to find the source, which will be time consuming and expensive. obviously if this is the only action then so be it, but just wondered if any other owners of the 3.0 had experienced this before, and what the problem was? thanks.

Hello Rick from the Homeland,

If it were mine, I would keep it away from mechanics armed with spanners and other wallet emptying devises until you let us know if the car blows out any (generally white) smoke when the engine is revved to around 2000rpm - and held at that for around 2 mins - when hot. 

Simple things first:- carefully look around the engine and cooling system for any signs of red deposits (assuming OAT coolant is in use). When you have done that and perhaps failed to see any evidence of a leak, remove the undertrsy if possible, and clad the floor where the car is parked with cardboard or similar and leave overnight ( placing the cardboard there as soon as the car is parked up after a run). Any significant leaks will obviously cause damp patches on the cardboard. Also carefully inspect the radiator core for evidence of staining. 

A worth-a -try 'investment' would be to replace the coolant reservoir cap with a new one - not off E what's it, but from the VAG dealer! 

If all of the above fail to find the answer then there are other non-dismantling tests which can be carried out to try to find the source of the coolant usage. 

Kind regards,

Gareth.

 

 

thank you Gareth, I will give that a go, much appreciated.

 

Rick