Clesa

Hey,

Im having a problem with my Q7 2007 4.2TDi. Few days ago i stopped and left my car for 15-20mins. When i came back i saw a puddle under the car, as i got closer i was sure its coolant. I opened the hood and saw that the whole front end of the engine was covered with coolant. Topped it off and drove back home 15mins, during that time it didnt leak that much again. Upon checking i saw that the small rubber pipe on top of the waterpump/thermostat was really worn out and it looked like it came from there so i ordered a new one plus a new waterpump and some other gaskets while im down there. After changing everything i didnt see a leak anymore. The day after that i was driving on the highway (120Km/h) when i suddenly got red low coolant alert, so i stopped immediately and opened the hood. Everything was covered with coolant again. Topped it off and drove back home and now i cant find where it leaked from. It looks like the pressure inside the coolant system gets too high. I changed to coolant tank cap as well but its still the same. If i open the cap after letting it cool down there is still pressure inside it and coolant flows over the cap. Coolant inside the tank is not bubbling. Now im thinking if its the head gasket(s)? Car has never overheated. Im thinking of buying the tester kit for the headgasket. Thought that maybe someone here has had any experience with this kind of problem.

'10Q7TDI_Prestige'

Since it is all over front of engine, be sure to check for coolant pooling in the engine valley, which eventually will overflow and run down front of engine from the top, etc. That's actually pretty common coolant leak on the V-6 TDI 3.0L engines, but the actual leak is likely at the EGR Cooler's coolant bypass valve. The EGR Cooler itself will eventually fail internally also, and consume coolant that way as well.

This leak can go on for a while undetected as you can't see the coolant pooling inside the engine valley, and the coolant loss is usually slow/steady, etc. Honestly though, on a 2007 you want to double check everything that hasn't already been replaced, and remember there is more than one coolant circuit on this car. Snake a simple probe or camera device down into engine valley to check for a lake of coolant.