856 blowing water out radiator

Anonymous-0 · Mar 10, 2009

I put a motor out of a 1256 in my 856 last spring. It runs good, uses no oil, has power and does not run hot but you can run it for hours a a high rmp, 1800 to 2200 but when you go to idle it down it will blow water out the over flow every time. Never blowes out when pulling only when you shut the throttle down at the end of the field. Have to add around one or two gal. to rad. each day. Anyone have an ideal whats going on?

Brian Bell · Mar 10, 2009

Have a thermostat in it?

NawlensGator · Mar 10, 2009

What I think: Cylinder wall themperatures are hotter at higher rpms because heat is being generated at a higher rate. Water circulation rate is also higher and water temperature remains about constant. Water circulation rate decreases at lower rpm so water temp around the cylinders increases. The higher temperature causes water to vaporize (bubbles) around the cylinders which displaces liquid water out the overflow. This is a temporary situation since the water flow slows immediately while the cylinders take time to cool to a lower temp.

If you don't refill the radiator, the water level will decrease to a point where it won't overflow anymore. If you keep the rpm's up for awhile after the load is decreased it may overflow less when rpm's are lowered.

Anonymous-0 · Mar 10, 2009

This was a common problem with the introduction of the 66 series, IH's answer under warranty was to have dealer install expansion tank, then they changed to a internal baffle in the radiator later on. If you can keep the coolant level just to well below the top of the tank but still covering core you should be ok. If not, the cheapest easiest fix is a recovery tank.

mkirsch · Mar 10, 2009

That may be what's happening, but it shouldn't happen. We used to work the snot out of our 856 pulling a 16' disk and 16' drag in tandem along with a 16' length of well casing that would load up with dirt. Never spilled a drop of water.

Not being a diesel expert, would it be possible that this is a head gasket problem even though you aren't finding any oil in the water, or water in the oil? Could the head gasket have failed such that cylinder pressure is leaking straight into the water jacket?

Hugh MacKay · Mar 11, 2009

Larry: Your trying to keep the radiator too full. The coolant must have room to expand. As the fan slows down the coolant heats up. You may think it hottest when pulling steady and hard, heat actually builds up as fan slows down after that hard work. Keep your coolant in most Farmall tractors 2 to 3 inches below cap.

856 blowing water out radiator

Anonymous-0

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Brian Bell

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NawlensGator

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Anonymous-0

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mkirsch

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Hugh MacKay

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