On Saturday I got a nervous call from my girlfriend when the Tiguan told her to pull over and check the coolant with the coolant warning light on and an alarm sounding. The fluid was low, and I told her to just top up the coolant container with water to get home and I'd take a look. On a couple of occasions before I had noticed the coolant level was low and had topped it up without really thinking about it and why it had gone down. This incident prompted further investigation.

After checking the level, test driving for a while, then parking the vehicle to see if there was a leak, there was nothing. I was confused and it seemed the only solution was to do a pressure test of the system. But then today, with the front right wheel off to replace the leaking bevel box seal, it was immediately noticeable that there was a leak from around the water pump assembly (credit to Umai Nai for pointing it out to me).


It seems this is not that unusual, and I presume it would be because I had the water pump replaced when the timing belt was changed. Because it isn't that bad, I am thinking of just carrying on with the topping up every few months until it gets bad enough to warrant removing the pump and re-doing the seal. I know that's slack and far from ideal, but I'll cop that. I just thought that for anyone else experiencing unexplained coolant loss, telling you to check here might help diagnosing your problem.