Firstly thank you to all of you for the help trying to solve my high running fan,
after some extensive research and help from you guy's , i have come to the conclusion that is the thermostat not opening fully......so i will be changing it Tomorrow, any last minute advice for this procedure...?

All advice welcome.

 

The coolant temps reported in your other post sound normal. How did you conclude that your thermostat is not opening?

 

Hello Mikey,
I have come to this conclusion through past experience,i have had over 21 differant cars since i was 17, also every thing else seems to be operating as they should, A/C,cabin heater,relay, the fan will still operate at full in winter weather too on a short run(8/10 miles). The only thing that is not normal is the difference in hose temperatures between top and bottom .

 

A thermostat won't fix that. It's still regulating the coolant temp to within it's normal range apparently.

 

At the moment i am trying alsorts, so this is one of them, so far no one has come up with any suggestions that have worked, if it was in it's normal range then why is the fan operating on high on short journey's even in freezing weather...? this has been going on for 6 months now, as i have always done in the past "process of elimination" .As far as i know and have always surmised, a cooling fan will operate on high if....the engine temp is high due to, coolant lose, gasket failure,airlock,low oil, radiator blockage, radiator leak, long haul travel with out rest and or hill climbing , standing in traffic,or or very hot weather conditions with any of the fore most......right..? but most of these have been eliminated....apart from sensors. I have all the maintenance and service records from new, the expansion tank was replaced only 5 years ago , i have also checked this for leaks, new condenser hoes's have been fitted, oxygen sensor, and it had a major service when i bought it........the thermostat is another elimination process....the reason i am doing this is because after a hard acceleration (or short burst of power)....the fan when to off, also leaving me to think the thermostat might not be open fully, also after leaving it to idle for a short while after a journey...again the fan goes off............so now i have given you as much information i can ....what would you say the problem is........?

 

Not sure I agree on the need for a new thermostat, but who knows. Hope it helps.

One bit of Clavenesque trivia:

The S-type thermostat operates 'backwards' from what you may be used to. When the coolant is cold, the thermostat is open, allowing flow through a bypass around the radiator. When warm, the thermostat closes the bypass and directs the coolant flow through the radiator for cooling.

This difference won't really change anything, just something to be aware of while troubleshooting.

 

Sorry for any confusion, but my statement above isn't correct. The S-Type thermostat is different from the conventional style, but not really backwards. You can read a long-winded explanation here, in post #41, complete with pretty pictures:


https://www.jaguarforums.com/forum/s...-182133/page3/