KeithLS400

Hi all i have just replaced the thermostat on my car and it doesn't seem to overheat anymore the temp guage stays just under halfway but the water system still seems to be pressurised ???? after a ten minuite run sticking my right foot down the temps ok but the pipe on the right of the thermostat housing seems quite hard and warm and when i losen the expansion tank cap the water rises and starts flowing from the overflow pipe ??? not as bad as it was and before though. should the water system be pressurised as much as it is ??? anyone shed some light on the problem ???? any ideas would be greatly appreciated before i scrap it or sell it for spares lol Keith

Hi Royt I will try that suddestion as it seems simple and cheap to start with Keith

Hi all i have recently purchased a 1994 LS400 all has been well with the car until this evening I was driving and noticed the temp guage started rising above the halfway mark heading towards the red line i stopped the car and as i went round to the nearside i noticed water steadily dripping on the floor (from the overflow in the expansion tank) i let the car cool down for a few mins and decided to gently loosen the cap on the expansion tank as soon as i had turned the cap slightly boiling water and steam started to pour out i let the engine cool down and totaly removed the cap added some fresh water to top it up then ran the engine up after it had been running for a few mins it started boiling over and both hoses from and to the thermostat housing where rock hard and very hot !!! there seems to be too much pressure or an airlock in the cooling system ???? anyone else had a simular problem and have a simple cheap cure ??? thanks Keith