Bam

edit: really hope there's no residual / long term overheat damage though.. strange failure mode for these.

 

Is there anyway to tell? Would that result in performance issues, or just parts that fail sooner than expected? (At 120k, everything is kind of expected...)

 

I mean the ECU also receives an input for cylinder heat temp, which may be what kicked it into overheat protection / ignition map. That sensor will rear high temp values regardless of coolant flow. I was unaware that lack of coolant flow would result in normal temp readings though (and no message center warnings) - that's kinda alarming.

As far as long term impacts - it's really impossible to tell. I suppose you could run a compression test on the motor and note the results, but that's something you'd do if you were bored and had two hours to blow during a weekend or something. You could probably rent a compression testing kit from advance or pep-boys, etc.

I really can't think of any other easy way to gauge the health of the motor. If it's not misfiring, doesn't exhibit any unusual or excessive noise, and the valves/heads sound normal as well, then all you can really do is keep driving it.

For the record though, ~120k mi SHOULDN'T be anything for these motors. Jaguar learned a lot of lessons with the earlier AJ-V8 4.2s which had been floating around for many years before LR adopted the design. Cam tensioner and some other major flaws had already been identified and fixed. With proper maintenance and care (and some good fluids) this really should be a 200k-250k mi. motor.