98 XJ8 Calorstat Thermostat - mod required to make it fit
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Since completing the transmission rebuild, I've been busy catching up on outstanding mtce routines on the Jag....
I also changed out the thermostat & coolant as part of the winterizing program for the family cars. The OE p/n is AJ86484 with the OEM supplier being Waxstat. This past year I had been having the fans run on occasionally post shutdown regardless of how warm it was (and it never gets really warm on Vancouver Island) so I was pretty sure the thermostat was on its way out.
The following is an FYI on the thermostat I ordered, a Calorstat p/n TH5753.84J - which is shown in the Calorstat catalogue as a cross reference to the OE p/n. Dimensions and temp (84 C) all matched OE so I ordered it.
When installing the unit I found that while the dimensions are correct, the Calorstat has a raised circular central section while the OE unit is flat. While this shouldn't have been an issue, the plastic (OE) thermostat housing has a narrow (@ 2mm wide) flange inside the housing that butts against the face of the thermostat, presumably to help keep it in position. This flange hit the raised centre section preventing the Calorstat from being seated. On the Waxstat, the flange just butted the surface of the thermostat.
Rather than return the Calorstat, which had come as part of a shipment of a winterizing material for the household cars, a process that would take several days, I was able to make it fit by shaving about 1mm off the top of the flange. This was all that was required to clear the raised central section and still left lots of material to support the thermostat in position.
This is a less than elegant solution and I think most would prefer to stick with a unit that fits right out of the box (NB I don't know if the flange found in my housing is the same on all engines or was changed in later versions).
Scott
ps - I've had no fan run-on since changing the T'stat, so am sure I found the cause of the run-on. I only read the post in the forum on lazy thermostats after the job was done, but that is exactly what I think I had.
I also changed out the thermostat & coolant as part of the winterizing program for the family cars. The OE p/n is AJ86484 with the OEM supplier being Waxstat. This past year I had been having the fans run on occasionally post shutdown regardless of how warm it was (and it never gets really warm on Vancouver Island) so I was pretty sure the thermostat was on its way out.
The following is an FYI on the thermostat I ordered, a Calorstat p/n TH5753.84J - which is shown in the Calorstat catalogue as a cross reference to the OE p/n. Dimensions and temp (84 C) all matched OE so I ordered it.
When installing the unit I found that while the dimensions are correct, the Calorstat has a raised circular central section while the OE unit is flat. While this shouldn't have been an issue, the plastic (OE) thermostat housing has a narrow (@ 2mm wide) flange inside the housing that butts against the face of the thermostat, presumably to help keep it in position. This flange hit the raised centre section preventing the Calorstat from being seated. On the Waxstat, the flange just butted the surface of the thermostat.
Rather than return the Calorstat, which had come as part of a shipment of a winterizing material for the household cars, a process that would take several days, I was able to make it fit by shaving about 1mm off the top of the flange. This was all that was required to clear the raised central section and still left lots of material to support the thermostat in position.
This is a less than elegant solution and I think most would prefer to stick with a unit that fits right out of the box (NB I don't know if the flange found in my housing is the same on all engines or was changed in later versions).
Scott
ps - I've had no fan run-on since changing the T'stat, so am sure I found the cause of the run-on. I only read the post in the forum on lazy thermostats after the job was done, but that is exactly what I think I had.
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