In the instructions it says do not over tighten the bleed screw and tight it up to number 3 position but on my 06 XJ8 the bleed screw doesn't have numbers so I don't know how tight it should be exactly. If you loose it little bit the water starts coming out slowly from it so I guess it should be tight enough to stop the water coming out?
Also in the instructions it doesn't mention that the bleed screw should be tightened after bleeding process or it has to be left always on number 3 position?
Sorry but I couldn't find the relevant sticky note/link on the top of the page or in posts? Can you send/attach the link please?
Thanks for attaching the relevant section.

 

Hi Alex
The instructions say tighten the bleed screw to 3 Nm. Nm is a metric measurement of torque as in Newton-meters. The car is British, so is European, and they use Metric measurements for everything, including tools. It is equivalent to 26.5 Inch-pounds. That's a little more than finger tight. It is plastic after all, so just nip it up gently. Almost everything on the car has a torque figure.

The link for the manual comes out really long, but look in this post.

X350/X358 - 'How To' / DIY Repair & Maintenance

It's the middle post in the group of three 'sticky' posts at the top of the forum.
There's a list of sections at the top. You want section 21 or 22. Workshop manual.
Section 21 is the manual in one document.
Section 22 is the manual divided into 6 parts.
Right-click on the link and select 'save as' to a good place on your computer.

Hope this helps.

 

Installing a new expansion tank and a 183 degree thermostat today.
One add, instead of watching the dash temp gauge hook up a scanner and monitor coolant temperature. Shut off at 95C.

 

Started swapping expansion tank and thermostat. As thermostat housing was opened it was obvious the Stant (Motorad) thermostat is not for a XJR. Think it fits a Lincoln LS and Ford Thunderbird.
Was installing expansion tank and saw nipple on back was snapped off. Found in the bubble wrap. Quit right then. Spent several hours and now have a non-running car.
Hopefully Harper Jaguar will get one to me soon, and do a better job packing than previous provider.

 

Is there a lower temperature thermostat available. Found some that are 183 degree and will not fit but listed for XJ/XJR. They are one the piece thermostats. The correct the ones have four parts.
But all the correct ones I have found are 190 degree. Really want a 180 - 185. Surely a lower temp is made by someone.
Looking on line I found all kinds of non-usable thermostats and housings that cross reference to a x356 XJR. Some of the housings were comical they were so far off. They cover these mistakes by saying it may not look like diagram. But definitely does not like like an original.

 

Hi
If your VIN number is greater than G49700, the standard thermostat is AJ811788. It is used on a number of Jaguars, and is very common.
There is not really any point in specifying a thermostat with a ten degree difference. The temperature gauge is software controlled and reads mid-range over a wide range of actual engine temperatures. I think they wanted to reduce the time that drivers spend fixating on the temperature gauge, and to trust that the engine is not overheating if the gauge reads in the middle. I know I keep a very close eye on my V12's temperature gauge when I drive it, but it has no software control at all, and is very sensitive to overheats.
It was mentioned earlier about the plastic thermostat housing, but the XJR has a metal housing so doesn't have the same problem. Be sure to replace the sealing ring, fit the jiggle pin to the top, and torque the housing screws to the correct Newton-meter figure as in the service manual.
I hope this solves your problem.
Pete M

 

The cooling system is fine. I just would like a little lower normal operating temperature.
Coolant temp runs 93 - 95C. Ambient temperature runs 30 - 40C for six months a year. A really cold night is below 10C.
Had the car over seven years and never turned on heat. Or in any of over cars unless traveling. Or set it to where it would blow warm air.
Run AC 12 months a year in our cars and homes.

 

Replaced the thermostat housing, car shakes now with misfire codes, probably the mechanic messed something up. He opened the intake manifold to get access to the thermostat housing. He said shaking could be due to the intake gasket as it may need to be changed now. We didn't bleed it, will look into it again. Scanner was reading ECT 230F, that's probably the coolant temperature and seems high.

 

Hey Alex,
This seems a bit odd:
"...He opened the intake manifold to get access to the thermostat housing. He said shaking could be due to the intake gasket as it may need to be changed now. We didn't bleed it, will look into it again. Scanner was reading ECT 230F, that's probably the coolant temperature and seems high...."

230F is way too high. As others suggested above, need to test for combustion leakage before more damage is done. These AJ engines are very easily ruined by overheating. Sounds as if you may already have a blown head gasket. Next step is dropped ex valve seats/piston interference, at which point the engine is finished

Also, find an experiencedl Jag mechanic to help you going forward. Thermostat R&R doesn't involve intake manifold gaskets...though the thermo housing generally requires renewal

 

We did the bleeding and it doesn't overheat now, heat is working too. To replace the thermostat housing he took off the intake manifold so he can open the thermostat housing easily as it's hard to access down there. After installing back the intake the car was shaking a little with a misfire on cylinder 8. Before replacing the housing there was no misfire or shake. He said usually when the intake is off and on back then gasket should be replaced and that's most probably the cause of shake. I will look into it and test drive little more to see. Thanks