I'm about to replace the thermostat as my rad fans run on for around 10-20 seconds after switching the engine off even though the weather is pretty cold.
The gauges don't indicate overheating, but I gather they're just dashboard ornaments anyway...
The engine is a Jag replacement 35,000 miles ago but I have no idea about the water pump.
BTW.... The car runs beautifully and sweet as a nut.
Is there any way of checking the pump is ok without taking it all to bits, or would it be prudent just to replace it anyway?
I don't want to throw money needlessly at my car, but I want all to be AOK.
Prevention is better than cure, as they say.

Roy.

 

Roy,

The only two things to go wrong with the pump are bearing failure or the impeller breaking up. You can check for play on the bearing or leakage from the 'weep hole' in bottom of the Pump body whilst the Pump is in situ but can only really check condition of the impeller by removing the pump. (spinning the Pump should cause the coolant to surge or ripple in the Expansion Tank but this isn't a reliable test)

The early pumps got a bad reputation from the impellers breaking up. Later ones appear to be more robust. Colour of the impeller is NOT a reliable guide. The original problem ones were orange and later improved ones black or white but many of the aftermarket pumps available more recently have orange impellers.

I've changed Thermostats on my last three V8's and each time have bought a new Pump at the same time. When the Pump was removed it was OK in each case but I replaced it anyway once it was removed. If in doubt, take it off to check - it's only seven bolts. Odds are it will be OK but you never want to risk overheating a Jaguar V8.

Graham

 

Roy
My fans run on for a bit aswell,surely they are meant to do this with the heat generated under our bonnets!
Regards
Keith

 

in hot weather..standing in traffic yes..winter no..need to replace your themostat pronto..to be on the safe side..10 min job

 

I did query the heat run-on issue, but it was suggested that considering we've had pretty chilly weather recently, the fans shouldn't be running on.
I'm not really sure what to do about it.
Roy.

 

Bullet well and truly bitten now.....
I couldn't be bothered with the worry and doubt.
My black-beauty is booked in to Marshalls Jaguar for diagnostic/remedy next Tuesday.
Roy.