@simon posted:Thats correct, maybe you have cavitation into your engine because the long time of iddling there is not enough coolant flow into your engine.
I remember on a Mangusta this can be a problem.
Do you know for sure you have the right Cleveland thermostat or the Windsor themostat whit the block off plate ?
is your pressure cap on the pressure tankand not on the overflow tank ?
ignition timing not to early ?
when engine is on teprature , is the top of the radiator hot ? or cool ?
than it can be air into the system.
when everything is OK , for me it will be not such a problem that when a hot engine iddling for a few minutes the prsuure tank boiled a little.
there are some tools when you can check if there is exhaust smell into the pressure tank , that means a failed head gasket.
Simon
Thanks! And yes, right, brand new Cleveland T-stat with the block off plate. The pressure cap is on the header tank (the thank more to the rear end), the cap without pressure on the overflow tank.
Timing is also correct and the radiator was completly hot, the temp switch in the radiator switched on the fans.