I changed the spark plugs and coils after which the car started ran for about 5 minutes and then the temperature gauge began to climb to the overheating range. Although the gauge indicates a very hot engine, and the car starts to slow down and the dash indicate low power mode when I remove the cap from the overflow bottle there is no sign of an overheated engine.

I'm thinking that the thermostat is not opening and the water in the block is overheating or the computer just thinks the motor is over heating when in fact it is not!

Can anyone help me with the following questions?

1. Where is the themostat located?

2. Is the thermostat temperature activated or is it computer controlled in some way.

3. Where can I get some good line diagrams of the cooling system of the 3.0 S Type Jag engine?

Help!

 

JTIS is a free download here on this site. It will answer all of your questions above.


Question though, did you perform the correct purge of the cooling system? There are 2 purge screws that need to be bled, also found in JTIS.


A word of caution, the purge (bleeder) screws are made of plastic and are VERY brittle. DO NOT FORCE them.