Hello,

I just replaced my faulty thermostat in 1996 jaguar vdp, which was running at 156 degrees f. The new one runs at 194f. I checked the overflow tank and it is up to the top, but it is not hot at all, dipped my finger in and it is cold. This is after a one hour ride. Is this normal? Did the air not bleed out from the thermo change? It just does not seem right?

 

Unless there's recirculating flow through the tank, I wouldn't expect the coolant to be hot.

 

This thread is something of a coincidence, as i used my x300 for an errand today traveling about 25 miles and on my return I noted that my coolant expansion tank was not the slightest bit hot, not even warm, but it has been rather cool here this week and I always get the impression that x300s run a little on the cool side.

 

Thanks for confirming nothing is wrong, now I hope this winter I will get better heat!

Kevin

 

I've never checked my thermostat,but removed it once to flush and change the coolent , once the engine is started the temperature gauge does soon start to move but probably needs at least fifteen minutes or so before it settles down to its usual place which is just under the half way mark, it will fluctuate a bit but only under this point, I've never had it go higher even in traffic, hope I'm not tempting fate by just saying that!

 

I saw that my temperature gauge needle was going from normal to almost cold when driving and never really got good heat this winter. I bought a Blue Driver obd2 Bluetooth reader for my iPhone, I was able to monitor the temp when driving and it was going from high 140's to 156 f. I got a 88c thermostat and new gasket (this one does not use an O ring, had to buy the gasket separate). I installed it and now it runs at 194 f and the needle does not move and the heat is fantastic. I had the same symptoms and resolution in my 94 xj40. If your needle is moving, it might be time to change it. Also, mine takes only about 4 minutes to reach operating temp now.

 

dumb question -
where does the blue driver USB thingie connect to the car?

 

Hello,

It connects to the obd2 connector under the dash. Trying to figure why photo uploaded but I could not insert.

 

Well I've taken "Kevinls" advice and bunged in a new thermostat, now its up to temperature in minutes, and the gauge doesn't move from normal, many thanks.

 

Great! You will probably notice a smoother running engine and your fuel mileage should increase with a properly maintained engine temperature.