random_farmhick
Member
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?