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Upon removing the old thermostat, it's installed with a square section ring with a slit in it to seal both faces of the thermostat to the two housings, like this from 2:25
I can't see how the single O ring can work, as there is no seal between the housing halves.
From what I can see online, all the genuine and aftermarket thermostats are the same - is this an issue where the thermostat listed for the XJR is the normal X308 item intended for the plastic housing?
Secondly, I tried installing the new thermostat using the old seal as it was in pretty good shape. Unfortunately it contacts a lug inside the aluminium hose elbow.
Has anyone else had similar issues?
Thanks Housing showing the lug which hits the thermostat Old thermostat at the top, new one at the bottom. Part number The new one has a single O ring on one face only and also has a shroud, which hits a lug inside the housing elbow
Last edited by alistairolsen; Nov 25, 2021 at 07:32 AM.
Did you ever work it out? I just ordered the same thermostat but haven't tried to put it in yet. On the Jaguar parts website it says to get the AJ86484 which is what I got.
It’s not easy for me to tell from a picture if the new o ring has a slit on the inside all the way around or not. If there’s a slit, then it goes on the outermost circumference of the thermostat. Use the old thermostat as a reference. If the new o ring has no internal slit, then I’d suggest going to the parts store to see if they have the correct thermostat gasket. If you can’t get a new thermostat gasket locally and you can’t wait any longer for the correct gasket, dry off the old gasket and housing with a paper towel. Install the old o ring on the new thermostat, install the assembly inside the housing and apply a small amount of rtv around the top of the o ring. When you install the aluminum cap back on, there should be very little or no rtv being squished out after the 3 bolts get tightened down.
Did you ever work it out? I just ordered the same thermostat but haven't tried to put it in yet. On the Jaguar parts website it says to get the AJ86484 which is what I got.
Nope, bought another thermostat which was also wrong.
Originally Posted by Addicted2boost
It’s not easy for me to tell from a picture if the new o ring has a slit on the inside all the way around or not. If there’s a slit, then it goes on the outermost circumference of the thermostat. Use the old thermostat as a reference. If the new o ring has no internal slit, then I’d suggest going to the parts store to see if they have the correct thermostat gasket. If you can’t get a new thermostat gasket locally and you can’t wait any longer for the correct gasket, dry off the old gasket and housing with a paper towel. Install the old o ring on the new thermostat, install the assembly inside the housing and apply a small amount of rtv around the top of the o ring. When you install the aluminum cap back on, there should be very little or no rtv being squished out after the 3 bolts get tightened down.
No slit inside the new gasket as noted in the OP
Reusing the old gasket would be fine ( I tried that), but as mentioned in the OP, the body of the thermostat hits the inside of the elbow.
The fitment of this thermostat is just wrong unfortunately. I got another one from Euro Car Parts, which had the correct style of O gasket, but the gasket was too thin and the thermostat slightly too small in diameter and still hits the housing.
Does anyone have a manufacturer and part number for something which is known to fit?
Last edited by alistairolsen; Dec 20, 2021 at 10:21 AM.
Nope, bought another thermostat which was also wrong.
No slit inside the new gasket as noted in the OP
Reusing the old gasket would be fine ( I tried that), but as mentioned in the OP, the body of the thermostat hits the inside of the elbow.
The fitment of this thermostat is just wrong unfortunately. I got another one from Euro Car Parts, which had the correct style of O gasket, but the gasket was too thin and the thermostat slightly too small in diameter and still hits the housing.
Does anyone have a manufacturer and part number for something which is known to fit?
X308 XJR thermostat change
