Tell me if this is a dumb idea

As many know the 2-135/2-155 tractors are known for bad heat/needing to speed the engine up in order for you to get heat in the cab. I had the front off to some steering box work and was looking at it. I went to change the thermostat and it is completely open through for the bypass back to the water pump, unlike most other tractors/engines that I ve messed with that have a bypass a quad to half the size of the upper hose/thermostat inlet. For instance, a 9420 deere with a 12.5L engine only has about an inch bypass, where the upper hose is 2 1/2-3 inches, and a comparable tractor, a 4440 has about a 2 inch upper hose, but only about a 3/4" thermostat bypass. So anyways, I was thinking that until the thermostat fully opens, most of the water will go either back to the water pump, or radiator depending on how much the thermostat is open, causing a lack of pressure in the block/upper water manifold compared to the other examples i gave. I put a restrictor in the bypass going to the pump. I made it 13/16 which is about half size. People get confused because some equipment actually has pressure checks for block pressure, which is different than the radiator cap pressure. Even on a 7 pound system, some things can have upwards of 40-50 pounds of pressure with the engine up to operating temperature. That pressure is what pushes the water to the heater. So after that novel, good idea or take it back out before I put antifreeze back in it?
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I don't know, but have you considered a 12v inline pump? I guess maybe it would have to have a switch and maybe a bypass?
 
(quoted from post at 21:02:32 03/28/23)
I don't know, but have you considered a 12v inline pump? I guess maybe it would have to have a switch and maybe a bypass?

I have thought about that, have seen people do it, but want something that I can do and forget it. Not worry about it leaking, wiring, switch, or forget about turning it on or off. I m trying to "fix" the issue, not put a bandaid on it.
 


Fair enough. I think your solution makes sense and is worth trying, if the rest of the system is in good working order, no flow/core issues.
 
(quoted from post at 23:41:42 03/28/23) Might be a dumb question but have checked your hoses? I
had my collapse under the cab.

Dad bought this tractor in the early 90 s, and granted i was only born in 87, it s been this way as long as I can remember, even after I put new hoses on. I did make it better several years ago by rebuilding the water pump and paying special attention to how far I pressed the impeller on to get it as close to the housing as possible, about 0.010" like deere water pumps that I ve rebuilt tons of. It had almost 10 times as much clearance before at about 0.095". Getting it closer made it so it had better flow that the tractor didn t run as warm and would keep heat going at 1000 rpm and up, but idle it down and it would still lose heat. Before anything under about 1500 you would lose it. Asked a guy who worked on these for years (and actually rebuilt this engine for dad) and he said most were like that, but not all.
 
Granted it s only 40 degrees out here, but at least initially it seems that it s working as planned. I can t be in the field working, but it s not getting the engine too hot, didn t seem to get up to temp any quicker or slower. Good hot heat even at idle. I shut it off after warm, and started it back up and left it at idle and it kept heat right away. You can feel the pressure in the feed hose compared to the return, especially when you speed the engine up. So as long as it is still alright when I m working in the field this spring, I think it ll be a pretty cheap solution.
 

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