Hi guys was just wondering if it would be easier yo replace the engine or the head gasket.
Symptons i have are whilst driving round town temp sits in middle but fans come.on constantly. On a run at 75ish temp boils right of red line. Slow to 60 drops to normal as.quick.as speed drops

Bought from bloke who said put went and he replaced it. Thwre was no heat from heaters which i sorted by flushing system completely and fillin heater by disconnectin pipe from back of stat housing. Still boiled up. Took stat out now temp sits between 95-116 from the dash trick. Bubbles in expansion tank. So thinking the gasket has gone. But what is the easier job. Pls