2001 XJ8 VDP Cooling System is building up way too much pressure and is now running hot. The water temperature reading is 220, and the temp. gauge now at 3/4. The hoses are expanding and are now filled with pressure and antifreeze even after car has cooled down when hoses should be empty.


This is what has been done:


(1)The 3 way connector for the left side heater hose (heater return) was replaced (nipple had broken off) along with the feed and return heater hoses---all under the intake manifold. Old hoses were very mushy from all the excess pressure.
(2) New intake manifold gaskets
(3) New fan water pump housing polished and new gasket
(4) Fresh Antifreeze


Head gasket is fine. Why is all this pressure building up?

 

How old is your thermostat?

 

Test coolant for hydrocarbons with a tester @ the reservoir. Could be leaking combustion past head gaskets into cooling system. the only way to eliminate head gaskets.

cooling fans running?

air bound? (air trapped in system)

just thoughts.

 

I suspect the cap for the pressure tank is faulty.

 

How did you decide the head gaskets are fine? And the cap should release pressure, so I am with RJ, the cap is suspect even if some other problem exists. So where the intake gaskets and other work done to try and fix this or some other problem, or is this the result of that?

 

That was one of the problems along with a thermostat that was sticking! Thanks again!

 

And thank you for getting back to us.