That's a good point, as already pointed out, it's not an engine that suffers head gasket issues, I don't know what or how things get cooled on these engine'sI'm not familiar with that engine, but does it have an oil-water heat exchanger for an oil cooler or transmission cooler?
Maybe, just maybe...
Thanks for the heads up, I had the reservoir off and cleaned it all out before it disappeared and I have a new reservoir on route for them.McK,
Hoping your local Jaguar guy finds the root cause for a permanent reasonable cost fix. One more thing about oil in the coolant Left unchecked, it can sometimes create a precipitate sludgy material in the cooling system. If this clogs your heater core (like it did in my wife's then new Nissan POS Xterra over two decades ago), it can be a much bigger costly job to rip apart the entire dash/firewall to replace the actual heat core which usually can't be blown out to unclog.