The Jag needs a new water pump.
There companies that make parts for classic cars at competitive prices.
Parts are only part of it I have been told that Jags are somewhat of a bitch to work on
I've been told it depends. The older ones, made when Jaguar was owned by British Leyland, had serious quality issues. That's when Jags got their reputation.
The ones I have owned are all designed and made during Ford's ownership. My mechanic says they are far easier to fix and apart from a few well-known issues, the quality is significantly better. He frequently points out that the German competitors (MB, BMW, Audi) have far more serious issues.
But he is biased, of course. He owns a Jaguars only shop.