Graham, My cap on my 98 is super hard to screw on and off. I did a coolant flush, new water pump (my original plastic impeller was ok), filled with OEM jag coolant, replaced the plastic T-stat housing with metal (plastic was ok), and and a beck arnley t-stat. Do think it's in my best interest to replace the expansion tank cap as well ? Thanks If so, should I go to the dealer, or online ok? __________________

 

Only place I could find one was dealer. I used Gaudin Jaguar in Las Vegas. cost was about $33

 

My cap was extremely tight when I bought my car. It has since become much easier to turn, probably because I check the coolant level a couple of times a week. I would not be concerned.

 

I replaced virtually every hose, hose clamp, thermostat, reservoir tank, cap, etc. with brand new parts. My brand new cap was tight, too. I had to use a thick rag with channelocks to remove mine.