Some time back I had an overheating problem on my 380sec.
It seamed as if the thermostat was not opening and a pressure was building up.
I tracked it down. On the thermostat housing is a fitting for a small bore pipe which goes to a T joint and one side then goes to the radiator and the other to the expansion bottle. If you remove the pipe from the thermo housing, connect another piece of pipe to the nipple and see if you can suck thro it. There is a one way valve inside the nipple, which, if jammed, wont let out any air in the system, and stops the water circulating and the thermostat doesnt open.
It seamed as if the thermostat was not opening and a pressure was building up.
I tracked it down. On the thermostat housing is a fitting for a small bore pipe which goes to a T joint and one side then goes to the radiator and the other to the expansion bottle. If you remove the pipe from the thermo housing, connect another piece of pipe to the nipple and see if you can suck thro it. There is a one way valve inside the nipple, which, if jammed, wont let out any air in the system, and stops the water circulating and the thermostat doesnt open.
