throttle housing flow

can anyone tell me if the coolant flows through the throttle housing at pressure my p38 is flowing through with quite a bit of force behind it when the car is ticking over you can see it bubbling in bottom of coolant resivior when you give it a rev it hits the roof of the coolant resivior,dont think this is normal can someone help please.

Blocked radiator small top pipes -Head gasket failure or slipped liner symptoms most likely

small top pipes on radiator are clear, coolant system pressurises and blows of. the harder you drive the car the quicker it will blow,tried a sealer which made no differance what soever thinking of burning it

Classic Head Gasket and possibly liners if it's a v8 get garage to do HC test with gas analyser over open coolant tank with engine running-if they jump from background.