Hi guys I need help I have problem with my cat
the car shut down by itself I didn't know it was because of overheating I opened the boot and I saw smoke and coolant was boiling any way I let it cool overnight and then I removed the thermostat and add coolant and start the car I heard loud cracking sound I highly believe it's the secondary tensioner bank A anyway I start the car and thermostat off
The temperature needle was rising very slow I noticed coolant leak but there was coolant in the reservoir half full
anyway since the temperature needle was going up and the thermostat was off is that mean it's head gasket is gone ?
Water pump is new there's tiny coolant leak
AC system works as it should
Radiator and fan also was working fine I highly believe the thermostat closed and stopped working .

Any idea ?
tomorrow I will tow it to my friend and he's mechanic

Thanks

 

Without thermostat, the engine will overheat. You need to have a good thermostat in place for any further testing.

 

Okay there was many leaks in the coolant system fixed it thankfully no head gasket damage we install new thermostat the obd read 220F AC on I believe that's the normal temperature. Thank stano

 

220*F (104*C) in my opinion is still high. Down here in Florida in my SV8 I get 203*F (95*C) with the A/C on as the average. If it’s really hot outside and I’m in stop and go traffic like a vehicle accident way up ahead, I might see 208*F (98*C) at most. You could also look in front of your radiator and condenser to see if there’s a lot of debris. I use an air compressor and a long blow gun wand to blow all that small debris out. Also, make sure both of your cooling fans are coming on low speed and high speed. If you’re ever in a situation where the engine is overheating, turn the A/C button off and heater on maximum with blower set to high speed.

 

195f while driving and at stop light 220f there was leak in the radiator itself and the reservoir cracked now no leaks thankfully and the fans working as it should. The Funny thing is my other xj8 need rear main seal . I love my cars but I believe we all agree beyond the 100k jag start fall unfortunately

 

Agreed across the board…. the only thing I would add is that with the clamshell hoods on these cars you can also pop the hood to help more of that latent heat dissipate which is an old XJ Series 1-3 V12 trick. They also didn’t like to run hot and some owners would routinely pop the hood when parking rather than rely on the cooling fans alone to do that.

 

Ken, don’t forget the XJS V12’s for that same trick. The aluminum radiator and dual electric fans are a great upgrade for those things. That is *IF* that one guy who makes them (if he’s still making them?) actually sends the product.

 

I suspect that most fails on these cars have to do more with age than mileage. Proper maintenance
will go a long way towards a trouble-free Jaguar. That said, there are always those Jaguars that have
had the "something to prove" mentality behind the wheel and those will be less trustworthy.