Mowing Kubota diesel overheating.

[4570Man]

 

[Menagerie-Manor]

Well this might not be the by the book method to flush a cooling system but it looks pretty flushed and confirmed the water pump is working.

Nothing wrong with a straight water flush.

 

[Williy]

In hot weather, antifreeze keeps the water in your engine and radiator from boiling over and in cold
weather keeps it from freezing
JUST PLAIN FACTS!!!

willy

 

[sandman2234]

In hot weather, antifreeze keeps the water in your engine and radiator from boiling over and in cold
weather keeps it from freezing
JUST PLAIN FACTS!!!

willy

I am not sure I agree with your statement in full. While it does prevent freezing, the boiling over is typically done using increases in pressure, which raises the boiling point. Antifreeze keeps it from freezing and has additives which reduce the corrosive properties of pure water. Most antifreeze actually reduces the disbursement of heat, in a minor amount over distilled water, which was what I have been taught, and is easy enough to check.

My thoughts about the original issue, was very similar with a Ford 1100 subcompact I own. It had a creeping temp, and I used a water hose to bring it back down, and it would eventually climb back up when I was working it hard on a hot day. It turned out to be very small particles that had gotten trapped deep inside the radiator which did not allow for a good heat exchange. I had washed the radiator out numerous times, using a water hose which flowed very well thru the fins. I finally removed the radiator and pressure washed it using pressure (be carefull not to damage the fins/tubes). The amount of foreign material that came out was unreal, and I had no clue that it was there. For some reason, I don't remember that there being light capabilities which should have told me that there was foreign material lodged in the fins.
Another thought, in this line of thought was a 1979 Chevy Chevette that my Wife got new as a high school student. She kept that car a lot longer than I wanted her to, but that is another story. The thermostat was sticking and because we were on a trip with time constraints, I simply pulled the thermostat and replaced the housing. If my Wife drove the car, it would overheat in a hurry, while the slightly more aggressive driver would be able to drive a considerable further distance before it overheated. We spent all of our extra time cooling the car down, which made for even tighter time constraints, so replacing the thermostat was put off until we got back. As soon as I replaced the thermostat, the problem went away. Seems the water was going thru the radiator too fast to be able to cool completely and it would slowly build up the temperature till it overheated.
Make sure the thermostat is opening AND CLOSING at the correct temps, and do a really good job of cleaning the accumulated crud out of the fins.
David from jax

 

[4570Man]

I just finished mowing about 2 acres with the straight water in the radiator and it didn’t overheat. The gauge stayed in the middle of the range. Checked with my ir thermometer the block is about 210 degrees and the radiator is 190.

 

[Midniteoyl]

In hot weather, antifreeze keeps the water in your engine and radiator from boiling over...
JUST PLAIN FACTS!!!

willy

Nope:

"Note! The specific heat of ethylene glycol based water solutions are less than the specific heat of clean water. For a heat transfer system with ethylene glycol the circulated volume must be increased compared to a system only with water.


In a 50% solution with operational temperatures above 36 oF the specific heat capacity is decreased with approximately 20%. The reduced heat capacity must be compensated by circulating more fluid.


Note! The density of ethylene glycol is higher than water - check the specific gravity (SG) table above, so the net impact on the heat transport capacity is reduced. Example - the specific heat of an ethylene glycol water solution 50% / 50% is 0.815 at 80 oF (26.7 oC). Specific gravity at the same conditions is 1.077. The net impact can be estimated to 0.815 * 1.077 = 0.877."

Ethylene Glycol Heat-Transfer Fluid Properties: Density, Data & Charts

Properties like freezing point, viscosity, specific gravity and specific heat of ethylene glycol based heat-transfer fluids, or brines.

www.engineeringtoolbox.com

______

"The specific heat capacity of ethylene glycolbased water solutions is less than that of pure water; in a 50 percent solution, ethylene glycol's specific heat capacity compared with pure water is decreased at least 20 percent at 36 degrees and about 17 percent at 200 degrees. Propylene glycol, another common coolant, has an even lower specific heat. Assuming a 100-gpm (gallons/minute) coolant flow rate and an energy loss through the coolant system of 189.5 hp, the water temperature increase would be 10 degrees, the ethylene glycol water mix would gain 20 degrees, and propylene glycol would gain 33.3 degrees.


Compensating for the reduced heat capacity of coolant/water mixes would require circulating more fluid through the system. Assuming a fixed amount of circulating fluid and radiator capacity, running 100 percent water would be the most efficient coolant in terms of its ability to conduct heat with minimal temperature rise. In other words, of all common liquids, water requires the most heat energy to change its temperature.

However, there are also differences in the vapor point of the three different coolants. Ethylene glycol and propylene glycol have higher vapor points and therefore can absorb heat at higher temperatures without boiling. Yet even with its lower vapor point, water still carries more heat per unit."

Glycol Or Water - Which Is The Better Coolant? - Hot Rod Magazine

The specific heat capacity of ethylene glycol–based water solutions is less than that of pure water. Propylene glycol, another common coolant, has an even lower specific heat. Of all common liquids, water requires the most heat energy to change its temperature.

www.hotrod.com

_____

And so on....

 

[the old grind]

Coolant doesn't go through the radiator too fast w/o a thermo'. (just too much flow to/thru it.) Lingering myth. A thermostat is also a restrictor/diverter to keep flow going through the engine block uniformly vs just dumped into the rad. A temp gauge won't tell you when top end is running hot from lack of flow when coolant doesn't circulate there as intended. That's why a thermostat's full opening is so much smaller it's bore. If the temp sensor was in the top end the variation would be more apparent, but it's usually not.

Racers use a 'washer' in place of a thermo to maintain coolant proportion between the whole engine and radiator. Without similar and proper coolant distribution the radiator is only cooling the block, not the top end too.

 

[Midniteoyl]

I just finished mowing about 2 acres with the straight water in the radiator and it didn’t overheat. The gauge stayed in the middle of the range. Checked with my ir thermometer the block is about 210 degrees and the radiator is 190.

Would still do a chemical flush then pull the radiator and do a proper cleaning of the fins. You *might* be able to use something like radiator cleaning foam, or acid, without pulling it, but I would just pull it to be certain.

And please do put a thermostat back in. More efficient that way as it not only allows faster warming, but also regulates the water in the block allowing it to absorb as much heat as it can. Especially from around the top of the cylinders and head.

 

[two_bit_score]

So straight water without a thermostat = no over heating? What does that tell you?

 

[RickB]

An important function of a thermostat is to create a flow restriction in the system that keeps the engine full of coolant and free of voids and hot spots.