> Hey all -
> I hope that life is good in Jaguar land. My mother's Jaguar has me a
> little bit flummoxed, and I was hoping that you guys might be able to
> She has a little problem with exploding thermostats. The first three
> lasted about 18 months each. The first went with a seized AC compressor
> that caused the engine to overheat, and the car was towed to the
> dealer. The dealer replaced the compressor, thermostat under warranty
> and returned the car. 18 months later on a very hot day again, the
> thermostat snapped closed causing an extreme overheating condition and
> the car was then towed to the independent garage who replaced the
> dealership when they were unable to service the car competently. Again
> the thermostat was replaced. 18 months later that thermostat went on a
> very hot day, and again the thermostat was replaced. That thermostat
> lasted about 1 month leading to an overcooling condition and inoperable
> heat. My mechanic showed me the remains of the thermostat, which was
> mostly lieing in the lower radiator hose when the clips to the housing
> blew apart.
> I had him replace the water pump along with the thermostat since I felt
> that there must be something else wrong with the car. It currently
> operates perfectly, but I have inspected the old pump, heated it and
> tried to get the impellar to spin on its shaft, and I can't really find
> a problem with the thing. Any theories as to whether the pump was bad
> or if there is something that I am overlooking? I have had the fans and
> fan switches checked and they are working at specification. I don't get
> it, and we are looking at selling the car if my mother can't rely on it
> to run.
> Anything that you guys can tell me about Jaguar cooling systems could
> help. Help! I am at a total loss.
The S-Type uses a pretty standard thermostat. I've had thermostats
"stick" on me in either the open or the closed position but I've never
had one "explode" and I'm not sure how an engine could possible cause a
thermostat to explode.
I would suggest making sure that you use a good quality thermostat but
if the work was done at the dealership then this should already have
been the case.
Even if the engine were overheating and the coolant pressure getting
too high I can't see how this would case the thermostat to explode. One
reason is that the hoses and radiator are much weaker than the
thermostat and they would go first. The other reason is that the
built-up pressure would be the same on both sides of the thermostat so
the pressure differential would be pretty negligible.
One thing to possible check would be the makeup of the coolant... make
sure the concentration/mixture is correct. If it isn't correct I could
see other longer-term problems but it's a bit of a stretch to see a
scenario where this would cause thermostats to explode.