poppet valve

[capnzee]

what is the function of the poppet valve? Can this function be eliminated? Would a malfunctioning poppet valve cause engine to overheat at speed then return to normal at idle? If so, what is fix? If not poppet valve, then what thermostats? Pee stream appears as strong as "sister" motor which is operating fine.

[reflect]

Poppet acts as a relief when thermostats are closed, so there's no excessive pressure in the block. If a poppet is stuck closed you would have crazy high readings on your gauge [when engine is still cold]. Stuck open, the water pump puts out so much volume there's enough water for reliefing thru the poppet and for cooling. I've run 2.5s with poppets removed. If water pump and pressure is good possibly NG thermostats.Put them in some water on the stove and see if they open.

[flabum1017]

could be a formed impeller (old), engine too high, blown gasket under the lower water pump housing (if a 2.5 or 2.4), restriction somewhere like plugged thermostats or blown powerhead base gasket.......