John deere 301 running hot.

[Billrog]

That's the purpose of the expansion ( over flow tank ) and when it cools it siphons back into the rad. An air breather that is clean plug up with grass & dust can also cause over heating.

 

[jcharley]

This tractor doesn't have or come with an expansion tank. I understand this is how modern systems work but seems odd that they would be designed to lose coolant every time it is operated.

 

[Billrog]

That should happen only when it's filled to the top of the rad once it's found the level of expansion it should be stable.

 

[jcharley]

Ok, I'll try not adding next time and see if it stops leaking just don't want to run it low on coolant. Thanks again

 

[KWRB]

Is the radiator corroded? A heat exchanger will lose effectiveness as the material corrodes. Don't sweat the overflow. Let it do its thing and overflow. It will only do so until it has the proper amount of coolant, then it'll only expand up to (not beyond) the point of overflow. I'm actually a little confused as to why there would be a vent cap if there's an overflow tube. I'm not familiar with this particular model.

Whatever it is, it doesn't seem like a coolant flow issue, given the water circuit work you've done. It seems like poor heat transfer. Are you sure when you clean the radiator you didn't bend the fins, thus preventing proper through flow of air? Also, sometimes the dust can really pack into a heat exchanger and you'd be shocked at how solid it becomes. I like to clean mine by using compressed air blowing from back to front, opposite the direction that the radiator got dirty in the first place, rather than front to back, which just tends to jam it in tighter.

Keep us posted.

 

[jcharley]

I appreciate the advice on the overflow, I would have kept filling it up and watching it run out. I was pretty carefully when cleaning the radiator but maybe I didn't clean it as good as I needed to. I'll try to blow it out with the compressor some more. Then when the new cap comes in and the weather clears up I'll give it a good test and put a load on it to see if it gets hot still. I don't think the radiator was overly corroded, there was definitely signs of some corrosion but might be worse than I what was visible. If it's still getting hot I will see about replacing it.
Thanks again everyone

 

[KWRB]

I want to re-emphasize the importance of blowing the debris back towards the direction from which it originally came. In a conventional radiator configuration, this means blowing the air through the radiator FROM BACK TO FRONT.

Good luck.