MF1240, overflow has coolant run out

[geekwithoutacause]

I went over everything on my new to me mf1240. I topped off the coolant a bit. As soon as I started it and it was warming up, the coolant started running out of the overflow hose. This hose runs straight to the ground. Since there is no overflow bottle like on a car I was wondering if this is normal. Perhaps need a new radiator cap? The current cap looks old.
IT says it is a 15psi cap.I doubt it is holding pressure since it's just warming up at idle, ambient temps about 75F. Engine runs great, doesn't overheat when I use it in the field.

 

[gary49]

Sounds normal. Coolant expands when heated, has to go somewhere, so it goes past the pressure relief on the cap. That's why engines generally have expansion tanks. My son has a MF1240, nice tractor, I'll look at it and see if it has an expansion tank.

 

[geekwithoutacause]

Sounds normal. Coolant expands when heated, has to go somewhere, so it goes past the pressure relief on the cap. That's why engines generally have expansion tanks. My son has a MF1240, nice tractor, I'll look at it and see if it has an expansion tank.

I'd appreciate if you could check. I don't see it on the manuals I have.
IT just seems weird it just runs on the ground. And it's not supposed to run out until it reaches 15psi or above. I found a replacement cap at napa. Will see how it behaves then.

 

[gary49]

It'll be a bit before I see it. Sometime in the upcoming week. I think your cap is fine. I'm old enough to remember when coolant systems didn't have expansion tanks and they all would expel coolant out the overflow tube if you didn't leave a little headspace in the radiator. Coolant doesn't have to boil to get to 15psi, it is incompressible and it expands whenever you heat it, even a few degrees. The "headspace" or air in the old style systems give the coolant space to put 15psi before it overcomes the pressure relief valve n the cap.

 

[geekwithoutacause]

It'll be a bit before I see it. Sometime in the upcoming week. I think your cap is fine. I'm old enough to remember when coolant systems didn't have expansion tanks and they all would expel coolant out the overflow tube if you didn't leave a little headspace in the radiator. Coolant doesn't have to boil to get to 15psi, it is incompressible and it expands whenever you heat it, even a few degrees. The "headspace" or air in the old style systems give the coolant space to put 15psi before it overcomes the pressure relief valve n the cap.

Okay, that makes sense. I guess I just filled it too much. I know about the pressure, it's raises the boiling point. I just thought it started spitting out the fluid rather quickly.