Summer has arrived here and offered a small project. A few days ago my 80k STR decided to run hot after a short drive. The radiator fans turned on as expected but had little effect. I stopped, shut off and let it cool a bit and restarted, ran hot again after the few blocks it took to get home. Later, I opened the header tank cap, relieved a bit of pressure, and the car has run temperature as normal since.
My best guess is an original and sticky thermostat. I see there are two temp ranges and some come with the elbow or "exit" as well as the the thermostat. Any suggestions about which temp and is the exit normally replaced? I expect to flush the system, refesh the old orange coolant the bottom hose gets replaced as well. Old coolant gets recycled to the parts house.

 

Place a Eurotoys low temp thermo in.

 

https://www.jaguarforums.com/forum/s...weekend-13342/


as a reference if needed. i just didnt take pics

 

After a single incident where the temp gauage was showing very warm on a cool day I decided a thermostat was sticking. Today I changed the thermostat in my 80K 03 STR with the Stant model. A t-30 torx was all that was needed to remove the cast metal elbow under the air intake. Drained the system by removing the bottom hose at the radiator, flushed and refilled with the Orange coolant
After idling a few minutes to burp the cooling system, the gauage indicated Red and the"hot Engine" message appeared. Shut down, checked the header tank for air, none. Tried again and got another hot indication. Ordered a new water pump should arrive tomorrow.

 

Remove the Supercharger cover and then open/remove the 19mm cap on the s/c coolant manifold. With that removed and the engine cool add some coolant and watch the coolant level in the s/c coolant manifold. Make sure the bleed valve is open on the expansion tank. When the coolant level starts to come up the threads on the s/c coolant manifold install the cap, close the bleed valve and cap on the expansion tank.

Start the engine and turn the heat all the way up and bring up to operating temperature. Shut down and top up expansion tank when cool. That should do it.

 

The final answer is..the cooling system had not been properly burped.
I tested the old and likely OEM thermostat. It opened, belatedly, two of three tests. But the overheating after the changed t-stat was likley trapped air. I had the reservor cap off, topped up and idleing for 6-10 minutes, heater on full once the new tstat was in place. But got a hot engine almots immediately once it reached operating temp...hmmm curious.. So I parked the car , nose high over night. The next morning , armed with the proceedure kindly provided by forum member searanch, I bled the SC and found I could add another 2 pints to the reserve tank which now had , overnight, accumulated some air. Thanks again searanch, you saved me an long forth of July installing a waterpump which was my next guess.
Now this kitty runs as cool as it looks. This car has been a learning experience but it is fast becoming my first choice to drive..thinking about getting an estimate for a repaint, love the orginal Jag Racing Green. It sat in the Texas sun all for its prior life and the clear coat is suffering ,the ground effects or side curtains are not my style...
" But honey just another 2-3 k and it will be very nice..." as we hear the door slam behind her ...
thanks again to the Forum
Phil in Tenn

 

I started getting over heating issues in the last week. I changed out the thermostat to a Stant 14718. Spent $16, stuffed rags over belts, three torx T-30 bolts and a half litre coolant puke.

Damn if that didn't straighten out a bunch of stuff. In the last month I have replaced the expansion tank (leaking from the bottom fill sensor) and the radiator (leaking from the lower drivers side metal tab).

I am now sick of the color orange...

 

While at it, it's a good idea to check the coolant temp. sensor with an ohm-meter, very easy and costs nothing. They can go faulty and break up inside making the micro assume the engine is at a different temp. than it really is. The ohms values at different temps. should be given in a spec. sheet for the device.
Leedsman.

 

I never had to "Burp" my coolant system. I just followed the Jaguar fill instructions after replacing the expansion tank(cracked at hose barb) and the sticking thermostat.

You simply ensure the bleed valve on top of the expansion tank is open(I removed it completely) when you fill the tank, close everything up, run it with the heat on high until it hits normal op temp,shut it down, and then repeat the procedure if you are still short coolant. Jaguar specifically states to NOT run the car without the expansion tank lid on.