The car is a 2002 XJR with just over 67,000 miles on it. After sitting in very slow traffic mostly stopped for about 15 minutes, car engine temp went to the maximum and the red light came on. parked the car, let it sit for about 25min, started it back up and drove home (15 min of driving). I turned everything(AC to 60 degrees, windows down, all the lights on, radio on (trying to repeat the problem), but the engine temp was normal the whole time.

It was hot today, 94 degrees or so outside when this happened

There was never a low coolant light (I will check the coolant reservoir tomorrow morning, once it is all cooled down, to see what the level is)

Is it normal, known, or has anyone else experienced their XJR overheating for seemingly no reason.

 

The 'no apparent reason' is either a thermostat or a cooling fan/sens failure.

The thermostat is a easy replacement.

Look for fan operation with the AC on. At least one should be running. No fan then you have to trace the temp gauge in the upper hose, fuse or other.

 

I'd vote for the thermostat. Sounds like it might be sticking...

 

I can't believe that you would still have the original T-Stat but here is an old TSB or 2

bob gauff

 

Thank you all for your responses, the fan is working and it kicks on higher (or another fan comes on or something) when it gets warmer. If it is really hot the fan will stay on for a few minutes after you turn the car off.

I looked at the TSB for the thermostat and my VIN is within the range of cars with a faulty thermostat, so I would bet that was the problem.

I will see to replacing the thermostat

 

let us know if replacing the thermostat solves the problem...

 

If it really is the original thermostat you are lucky you have no serious damage. Actually, same goes for the water pump. My water pump (plastic vanes) was coming apart when I replaced it (with a metal vaned one).

 

As far as the water pump is concerned, I thought that by the 2002 MY they had that figured out, but the TSB about the water pump (thank you motorcarman) has a year range all the way through for the X308.

The TSB references reading the part number off of the water pump, which would be very easy to do if the pulley was off of the water pump, but I am hoping to avoid removing the water pump pulley to check the number

I looked at my lincoln LS water pump (from disassembled engine) and the pulley seems to cover the number well

Has anyone been able to read their number without removing the pulley?

 

Pulley comes off in 5 minutes. Loosen the 3 8mm bolts about one turn, the tensioner is a 15mm loosen that and slide belt off of water pump pulley. Remove 3 pulley bolts and the pully itself. If u do it right the belt stays on all of the other pulleys.

 

I followed that procedure exactly and it worked, thank you. I can now confirm that my water pump is one of the good ones and will not need replacement at this time

 

Glad I could help.

 

Installed the new thermostat, not a hard job at all if you have the right tools, I am well equipped but this job required some odd things that I did not have. I had to get a 8mm universal joint type socket to get to the bottom bolt of the coolant pipe you remove to get to the thermostat. Also during the coolant refilling process, In order to remove the intercooler system coolant fill access I had to get a 19mm hex socket which was hard to find.

Took the car for a long drive and the engine temp did not rise above normal, problem solved, hopefully