Farmall F-20s and Water Pumps

Speaking of F-20s, they did not have water pumps. Their circulation of coolant happened by thermo-siphon, where the hot water in the engine rose up into the top of the radiator, and this flow then siphoned the cooler water from the bottom of the radiator up into the engine, and a cooling cycle occurred. My question is, how effectively did this cooling system work in the field when pulling a 2-bottom plow all day? Were these tractors prone to overheating?

Thermosyphon systems generally had a very generously sized radiator and temperature was controlled upwards by utilisation of a blind or some other air-flow control system.

No experience of your particular example but you would have to offer information about the size of the bottoms (10s to 18s?), their type, depth of cultivation, soil type (a major consideration), condition of plough, ambient temperatures and maybe some other variables before you hope to get a definitive answer which would prevail for your conditions.

The alternative is for every reply to offer you this information (for which you have not made any request) and then you would need to extrapolate or interpolate for your particular set of variables.

These systems worked effectively, in their day, and if they could manage an hour without overheating then a day would be no greater problem.

One of the potential problems with this type of system was that it was not pressurised and needed regular coolant top-up. If dirty or 'hard' water was used it could quickly diminish the effectiveness of the system.

Remember also that the condition of the tractor is a variable too. Often compression ratios were changed at overhaul intervals and the engine may be making much more power with, say a higher compression ratio or larger pistons and modern day fuels and produce more excess heat energy than when in original condition.

Regards, RAB

We had a 1947 JD B with thermosyphon. ON a good day, under heavy plowing load, there could be a substantial difference in temperature as you plowed into or with the wind. We had a auxillary water pump added. Nice unit, worked well.

Now have a '49 JD B with thermosyphon, never had any heating issues.

My grandpa bought a 38 F-20 new, and wore out several plow bottoms doing cusotm plowing with it. I plowed with it some when I was a teenager, and we never had any problem with overheating, as long as the waterlevel was kept high enough to circulate. We were pulling 2-16s and usually in 3rd gear. Usually as fast as the tractor would pull it. Dad had an early C which had the same cooling system, and we worked that tractor hard without any problems. One tim I did overheat it was because I didn't check the coolant and it got hot mowing gov. acres. Got hot enough to burn the valve cover gasket! If you keep the coolant level up where it should be and the radietor is not plugged they work good.