[Shuriken_57]

Originally Posted by SD1too

Thanks Brahim. A sealed cooling system, pressurising correctly, should run in the low nineties whether the car is moving at 35 km/h (20 mph) or 130 km/h (75 mph). It should only rise to 100° when the car is stationary for long periods.

Your symptoms are a classic case of an unsealed cooling system. This could be due to anything from worn expansion tank cap seals, a faulty cap, a loose hose connection, a slowly seeping 'O' ring in the 'V', a defective water pump gasket or bearing, a leaking radiator, inlet manifold gasket etc. etc., the list is almost endless. It will not be easy to find because there won't necessarily be drops of coolant visible.

It won't be a problem provided that you reconnected that hose at the same time as lowering the expansion tank back into its fixed position.

Simon

Thanks you Simon, i'll check when i can.