Coolant Flow

Want to install a temp sensor for monitoring engine temps. Does anyone know the coolant flow direction in a YZ250T, 2005 ? Does it flow from the radiator to the head, or from the radiator to the water pump..?

I believe it flows from the radiator to the head, so cooled coolant goes from the rad to the engine

Is it my cap? Was riding and my head fried my ring(no compression but no seizer) heads was hot as heck but rad was cool collant wasnt hot in rad?

Is it my cap? Was riding and my head fried my ring(no compression but no seizer) heads was hot as heck but rad was cool collant wasnt hot in rad?

Is your water pump working?

Yes just replace seal and impeller notice it lose compression rings loss tension immediate ly opened cap not thinking of explosion but no hiss or anything.

And what about the gear that drives the pump? I think it's plastic... Might be broken and then the impeller will not spin

Have two extra bottom ends for parts had all of the impellers, shafts and gears out all teeth were there no major damage.

Coolant flow in most engines is bottom to top so radiator to water pump to cylinder to head back to radiator.  To instrument coolant temperature you want to measure the temperature of the coolant coming OUT of the cylinder head.

Edited by 1987CR250R

Yeah but with a bad cap would it still transfer from head all the way back to top of rad if my cap wasnt holding pressure?

Yes, the radiator cap just keeps the water from boiling it does not affect the cooling capacity of the system.  As the system loses water less the water stops covering the radiator core and your cooling capacity starts to drop.  If the head o-ring failed and you lost water through the engine that would certainly cause an overheat. The radiator will feel cool because there is no water left to carry heat from the engine to the radiator.

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