Could someone please confirm if the rubber seal on the 4.2 thermostat is part of the housing or not. I've pulled the thermostat to change it and it left the rubber in. It looks like it's the original and didn't want to come out. I didn't want to force it and knacker it up if it's not meant to come out. I suspect it does need to be replaced but wanted to be sure before I pull it. Also will a 86degree thermostat be ok? It shows 84 degrees on the original but the replacement is 86. Many thanks for all help received.

 

When I got my new thermostat because mine stuck open it came with a brand new seal that went around the outside of the thermostat. I can't think 86C will be an issue, that is the temp that the thermostat will start to open so 2C isn't likely going to effect the peak temperature much if at all.

 

It's a good idea to replace the entire water outlet, which includes a new thermostat. The seal around the thermostat perishes allowing coolant to bypass the thermostat resulting in DTC P0128 being set and turning on the MIL.

The JLR part number for the water outlet is AJ811793.

 

Hi, thanks for the help. That part doesn't look like what I have on my car. I have a thermostat with a new rubber, just wondering if the one I can see needs removing from the housing.?

 

Bit the bullet and pulled it out. It's been in there for a long time and looked like it was part of the housing. Took a bit of cleaning up to get it off. Definitely not been changed for a long time. Lots of jag service history too. Oh well.

 

You're car has the aluminium thermostat housing doesn't it? At least my XKR does. Should just remove the rubber and use the new rubber on the thermostat that came with it. Taking the thermostat housing apart was just 3 torx bolts correct?

 

Yes I have realised now. It was in that well I wasn't sure if it was part of the housing. Thankyou for your help.

 

I found it really difficult to get to the torx screws, I had to use an allen key, and adapter and a torx bit to get it out and put them back in. It's the bend on the housing.