1. Fix the stupid injector. It's not causing your overheating problem, but it's still something you should fix. The oil leak isn't causing your overheating either.

2. How did you check the thermostat?

3. Overheating at highway speeds is often indicative of a partially blocked or excessively filthy/scaled radiator. A water pump problem is possible, but I would go after the radiator first. Try a flush and see if that helps.

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Whoever said there's nothing more expensive than a cheap Mercedes never had a cheap Jaguar.

83 300D Turbo with manual conversion, early W126 vented front rotors and H4 headlights 400,xxx miles
08 Suzuki GSX-R600 M4 Slip-on 22,xxx miles
88 Jaguar XJS V12 94,xxx miles. Work in progress.