About a month ago, wife.com was driving our 2002 XJR (same drivetrain as my new XKR). She reported the AC blowing warm.

Took it out for a test drive. AC was fine.

Right up until it wasn't, and the car suddenly overheated.

Limped it home, dead rolling it much of the way. Threw a new waterpump / thermostat in it, and all was well.

 

One other thing - we both noticed the fans running after the car was shut off. We thought it might be due to the heat. Record temps in Texas this summer.

 

what was wrong with your water pump? Did yours have the plastic impellers?

 

In a similar vein - was it the thermostat or the waterpump?

 

Yeah, 90k and plastic impellers.

Not sure if it was thermostat and waterpump, I just did both, both belts, and the coolant. Had to get that car on the road, and figured if one was due, I should just do them both. Penny foolish and all that rot. I mean, I love cutting up my knuckles on the radiator, but not so much that I want to do it more than required.

 

What happens to all of the little plastic pieces? Do they clog up the radiator? Seems like they would.

 

Last six of the XJR VIN was F49146. According to TSB 303-60, my car was in the VIN range that had the white waterpump impellers.

For future readers, Jaguars of this vintage had a waterpump design flaw. The early bad ones were black, the newer better ones were white. TSB about XJR/XKR waterpumps and their color is here:

https://www.jaguarforums.com/forum/a...pump-ident-pdf

Impellers were not broken off, but I did notice that they *seemed* to be cracking where they attach to the impeller axle. I am unsure on this point, since I didn't examine both closely to see what they should have looked like. I wish I would have taken before and after pics now so I could post.

We had record heat in Texas this summer. I noticed the fans running after wife shut off the car. She even noticed it. Since the fans didn't exhibit the same behavior immediately after I did the repair, I changed the behavior of the fans as well.

I noticed the AC being a little dodgy on the day before, when my brother and I were driving around. I don't remember the car being hot, and my brother (ex Jag dealer, knows Jags intimately) didn't mention it. I don't specifically remember looking at the temp gauge, since at that time overheating was not part of my mental A/C checklist. Which is why I am mentioning it now.

I don't think we can figure it out now, since if the either thermostat or water pump were cocked up, flow would be impeded.

I think the interesting thing is - why would the AC fritz? I am not sure how the AC lines run, but do they get close enough to the engine to get heat soaked? And would a failing cooling system really cause the outside of the motor to get that hot for that long? Or does it really take so little temperature elevation to cause it to fail?

These are the questions that come to me when I can't sleep at night

Good day, all.