Last year I had the water housing replaced on my 1996 Audi A4. Twice in the last 2 weeks the pipe that goes from the plastic water housing on the back of the engine to i "think" the heater matrix has just come off! Now am I right in presuming this pipe should have a jubilee clip on it as it didnt and I just pushed it back on after the first time and it came off again yesterday.

If it does need one can someone tell me what size I need as I need to go get one today but I cycle to work and cant measure the pipe.