Hi all, Just had the pleasure this week of discovering my water pump is shot. Wanted to share a few things and as always I defer to any experts who wish to correct me:

1) A few days ago the car showed low coolant, then the guage went up to the red at highway speed.
Lesson Learned: If you are like me you are paying 20% attention right now thinking "it will never happen to me". Get it in your mind it may - and be prepared to draw the line on what to do in which sequence when it does. When you don't have this mapped out in your head, you will be more than a bit stressed with the options when it does. Do I drive a few more miles, can I sit on the side of the road and move in 1/4 mile increments, oh I'll miss my meeting, how bad can it be, can I fix it myself later. . . ? Easy for me now: These cars don't overheat unless something is very wrong. Just pull over and call a tow truck, not worth risking anything else.
2) I pulled over turned off the car. I needed gas and figured it was just low coolant, and a gas station was just 3 miles away. So after a while I started the car, the guage was normal, decided to drive to the next gas station. Shortly I was faced with a 1/2 mile up hill drive, the guage shot into the red again. I couldn't pull over for several hundred yards, steam started comming out. Called a tow truck and waited. Had it towed to my mechanic.

3) The independant Jag mechanic had to take off the intake manifold to replace a hose with a leak ($850). Got the car back yesteray at lunch and drove her home. It was super hot out so I even left the roof up and A/C on high. After 9.5 miles, the A/C went warm, I looked down and saw the guage climbing towards the red (guess they are linked). The climbing temperature reversed itself and all looked OK (yes I considered the fact that a new thermomiter may be just breaking in - duh). I drove another 20 miles to the office, as I pulled in the parking lot - it went Red. I parked and shut her off. Listened - nothing escaping, no hisss.

4) Decided to drive the car to the mechanic after work but before rush hour. Chose no A/C to validate that wasn't connected. All was fine for 9.5 miles - the guage started to climb! I downshifted and rapidly the temp went back to normal. Kept an eagle eye on the guage after that. When I stopped for Red lights, it would climb. Increase engine speed = all goes normal. Thanks to your previous conversations, I printed and came prepared to show the mechanic the Jaguar TSB on the pumps with Black impellers.

5) As soon as I pulled into the mechanics lot, the guage climbed. I called him over and showed him. He imediately recognized it as the water pump, as soon as I reved the engine the temp dropped. Called me 5 minutes ago it is now ready for pick up. The water pump impeller was in peices.

I don't know if I burst the hose by driving it too hot. The low coolant warning would say no. But if this were ever to happen again, I'd put her in neutral and rev the engine for a few seconds to see if it dropped the temperature.

This was a real inconvenience. If you have a 1997 or 1998 jag with one of these water pumps (the TSB has model numbers and instructions on where to look for the number), you might think about preventive maintenance.

Guess I'll have to reprioritze my to do list and install my realtime guage which is sitting on my work bench.

As a side note - I was under the impression that the temp guage was limited in its ability to display what's going on. Mine seemed to track the temperature situation, though I admit it always moves to normal position within 2 blocks of driving. Anyone know more about this?

Thanks, hope it helps.

John

 

It appears you were lucky. I didn't think there were any original pumps left, but the first things I did when I bought my 97 was check the pump, replace the thermostat housing and install Realgauge.
There are new pumps with black impellers by Airtex, but I don't think it is the same polymer. The black is due to carbon black, not the polymer.
The factory gauge is designed to follow the engine temp. to 185 F at mid scale, then stay there until about 235 F, when it jumps and quickly reaches red.

 

Thanks RJ, I apprecaite it. John

 

And trust me, you are not the only one with a RealGauge kit sitting on their workbench - as I stare at mine - and say to myself - WTF, why didn't I install it - as I rebuild my motor...