My 2001 s type started overheating a couple Weeks ago. The temp gauge would go to hot the second later would go back to half. I changed the thermo and was fine until tonight. Went to h and right back to half. Any suggestions?

 

Any external leaks? Could be many things: water pump, head gasket, faulty thermostat but you changed it out - so rule that out.

 

Could be air trapped in the system. Make sure to bleed it thoroughly, then bleed it again.

 

When I release the cap on the overflow seems like there's no pressure.

 

There's always pressure on mine when hot.

Another "could be" is wiring.

 

Seems to be a leak somewhere. Added antifreeze and stopped. Thanks, now its searching time.

 

I had a similar problem with my 03'. It would run fine in town but would heat up on the highway. I had the thermostat replaced with a Stant from Advance Auto and it made things worse. I went ahead and got one from the Jag. dealership and it worked fine. The coolant lines had some air left in them and I needed to add about 8-10 oz of fluid but all is well.

 

There is a bleeder valve for the coolant- long rubber hose with a cap - it is near the brake fluid
reservoir.