[joncasey]

Hi there i have 2002 1.6 16v zafira. problem started when i broke down. i inspected the engine and as i opened bonnet the pipe snapped off the thermostat housing and coolant spat everywhere. New thermostat housing bought and a new stat fitted. Car was then used for a few days and was fine. then on a school run the temp reached 90c and the coolant light on dash came on and the fan cut in. now it does it all the time once engine reaches temp. the gauge doesnt drop or go above the 90c even when driving along or sitting in traffic but as i said the light stays on and fan cuts in and out all the time. So i then changed the temp sensor that goes into the thermostat housing and hasnt solved problem so i at a loss wot to do now. just to add the car runs fine still with this problem and theres no oil or gunk in the water tank and heads fine. PLEASE HELP

 

[fastjetfixer]

Air lock old chum. Some models have bleed points at various stages in the coolant system. Try and bleed it as best as you can. Especially the radiator, these are great traps for air.

Let me know how you get on, but your post is dated a while ago so it's probably old news.