Ronan

Thanks for the replies, Is checking for an airlock as easy as squeesing the pipes or would one have to drain the system and refill? As to the antifreeze being ok, I can only sumise that it is, had a full service history, or so I was told by the outlaws but will have to check! I might try and boil the thermostat, TY again R.

Two items of discussion here have peaked my interest on my search to sort out the heater in a 2001 LS430 with circa 155k miles onboard. Firstly the question as to whether the temp gauge differed when the non heating problem occured and secondly the fluid coupled cooling fan. Here is my present dilema, during the recent cold snap here in the West of Ireland the heater stopped working (or should I say didnt start working) one morning while the temp outside was below zero and the windows were all iced up(-2 to -8 range over the previous night). It was someone else driving the car when it happened so I didnt get to see the problem first hand until I had to drive the car on a long (very cold without the heater) journey. Every now and then, of its own accord, the heater kicked back in again from cold start or during the journey but never for very long. For a few days, at that time, it would decide of its own valition whether to work or not (I hate blasted intermittant faults). That was prior to the New Year. When the car was taken out a few days in to the New Year the heater remained cold on all settings , all sorts of cold air through each and every one of the different vent choices and hasnt heated up since (thankfully the heated seat was still working so it wasnt all bad, brrrr). The new problem however is that the temp started to rise towards the upper end of the scale on short journeys! Question 1 IF it is a thermostat problem would that lead A) to the heater not heating up, AND B) to the temp rise on the guage? If so could somebody explain the link? Question 2 Why doesnt the Fan manage the cooling from the sensor? Question 3 How would one diagnose the thermostat problem?