Hi, I'm losing water from my 1.9td it happened before and they replaced the water pump and solved the problem now it's come back a couple of months later. Taken it back and they now say it needs a new water housing two o rings and sensors, is this a easy job to do yourself? As the bits are cheap but they reckon it's a couple of hours to do so that knocks up the price alot. Anyone shed light on this??