Recently had the timing belt and water pump replaced by my usual local garage. Since then have noticed that the coolant level in the expansion tank keeps dropping. Can't see any obvious leaks or water residue anywhere as the result of a leak either. Is it possible the new water pump was faulty or a different failure. Car drives as normal, reaches 90 degree temp ok and stays there during driving. Having to put about 0.5litres in every 100 miles or so. Any ideas folks?