Correct Anti-Freeze Type

Is there a particular formulation of anti-freeze that I should use in my un-styled "D" - s/n 143458?

Is there a particular formulation of anti-freeze that I should NOT use in my un-styled "D" - s/n 143458?

I did not seal the studs correctly when I rebuilt the engine so coolant can get into the stud passages in the head.
If I only use water and some stays trapped in these passages, the head could crack in the winter.

Your advice will be appreciated !
JGC

50/50 mix of antifreeze will protect your tractor to -34 degrees

My experiences with 50:50 mix has been temps run high especially with a thermo siphon cooling system! Unless it has a water pump, the 2 cylinder JD gauges are most always pegged if they're working with a 50:50 mix. If you don't work it (a parade tractor) then the 50:50 is excellent because it's easier to keep the temperature up, the carb can be adjusted a bit leaner & the plugs less apt to foul!

Whatever you put in it, be sure to mix the water & the antifreeze together BEFORE you pour it in the D. Even pouring a gallon of water then a gallon of antifreeze still lets the antifreeze go to the bottom and he will likely boil over before he starts cooling. You'll end up with about 1/3 of your cooling system's brand new coolant on the ground!

I suspect you're really inquiring about using the old green stuff, ethylene glycol, vs using the newer pink stuff, propolyene glycol. I think I have that info correct. When I use antifreeze, I use the old style green stuff in my old tractors. However, I usually use just water and drain them in the winter. Antifreeze can discolor paint and leaks out easier than water.

When it comes anti-freeze there is a few things that need to be considered. First off is the types, ethylene and propylene. Both are glycol based but the major difference is that propylene is food grade, meaning that it can be used in proximity to food and drinking water thus it can be used in RV water lines and such, and ethylene is not. Then there is heat transfer. The greater the concentration of either type of glycol, the worse the heat transfer. And lastly there is protection levels. Most people do not realize that there are two levels of protection, freeze and burst. When a glycol mixture reaches its freeze point it turns to slush, when it reaches its burst point it becomes a solid and it is at that point where it burst pipes, cracks castings and so on. Burst point is quite a bit lower than freeze point.

So the level of anti-freeze you want depends on what you are doing with the tractor. Generally a 50/50 ethylene mixture with a freeze point of -50 or so, depending on the inhibitors and additives in the mixture, is overkill unless you need the fluid in a liquid state so you can operate the tractor at that temperature. Since that is doubtful, a 35% mixture of ethylene will give you freeze protection, or keep the fluid liquid, to 0 degrees and burst protection well beyond -60 degrees. This gives you better heat transfer than a 50/50 mixture will protect your tractor against very low temperatures. Propylene works the same except it requires a 40% mixture for the same protection and thus has a corresponding loss of heat transfer ability.

Thanks very much for the detailed explanation.
I wasn't aware of the slush and burst scenarios with glycol based anti-freezes.

In looking at available anti-freezes online, there are products with additive packages for Asian vehicles, for European vehicles, and products that claim compatibility with ALL
anti-freezes.

The original intent of my post was to find out if there are any problems using today's ethylene glycol antifreeze in my "D".
Sounds like it will be ok with today's ethylene glycol antifreeze

My compliments to you Sir! Very well stated.