Farmall model b

I recently bought a model b tractor at auction. Tractor starts and runs but overheats,I am pretty mechanical but cant find a water pump on this tractor, I hate to sound dumb but were there tractors produced without water pumps. I am also having a heck of a time locating the serial number, I have read that it should be on left side seat bracket, found a tag stamped 4.23.0 Any help would be great as I am new to these old tractors. Thank you Tom

Serial number is stamped on the block below the #1 (frontmost) sparkplug. It was also on the seat bracket BUT sometimes those are missing. I forgets how the coolant moves around but am not aware of a water pump. Others can give you more detail. The B is a nice little tractor without a lot of bells and whistles. Enjoy it!

the b is a thermosiphon cooling, no water pump. prolly need a good radiator cleaning and block flushing to get er clean. if the serial number is still there, best way to find it, sneek up on the tractor from behind, facing the back of the seat. with your left hand locate the brace that holds the seat to the deck. the serial number tag is located on the lower rear portion of that bracket, facing the inside of the other seat bracket. get in there with a flashlight, they are not the easiest ones to find.

Up at the front and underneath the left side of the tractor,just behind the center line of the ront wheels, you should see a hole in the bottom of the casting. If things are originalor anyplace near, you should see a pipe coming down through there, with a cap of some sort on it. The original had Mickey Mouse ears on it, but it could be any kind of cap. This is your radiator/cooling sytem drain. If there's nothing poking out, look above that, inside the casting, for an elbow with a pipe and cap or maybe even a simple plug in the elbow casting that might be the drain.

There are other issues that could be causing you to overheat, but I shouldn't doubt that it would benefit from as good a flushing as you can do in a thermosiphon system.

Drain it and, with the drain open, run a garden hose down through the cap for ten or fifteen minutes. While that's running, mix a couple of pounds of Arm & Hammer Washing Soda (NOT baking soda -- the washing soda will be right next to the 20-Mule-Team Borax in the laundry detergent aisle in your supermarket) into a two-gallon or larger pail. Mix it enough to dissole thoroughly, replace your drain plug, pour the soda and water solution in and add water to fill.

Then run the tractor and let it heat up. YOu don't want to let it overheat to wher eit causes damage, but energy like heat promotes the speed of chemical reactions, so let it warm right up. The thermosiphon is actually a pretty efficient system and it will circulate pretty actively when it heats up. Let it circulate. The first shot will likely get a lot of the crud out of the tubes on your radiator, as well as start to work on the pockets of sediment that build up at the rear of your head and around the #3 an #4 cylinder sleeves in the block. Run it until it gets good and warm and stop if it overheats again, then drain.

What comes out should be a nasty black. You can then try a running it with straight water to see if things are better, or give it another flush with hose water (after letting it cool down!) followed by another flush with washing soda.

If that doesn't ease the problem, you may have more sludge (it can really pile up!) than flushing will take care of, in which case you might pull the radiator and the upper engine outlet (that is also your fan support bracket) and the lower inlet, and nose a pressure washer in there to try and break up the clot.

If your overheating is not related to the cooling system, there are valve and ignition timing issues that could be in play, but I'd start with the easy stuff.

The B Farmall has a thermosyphon system to circulate the water. There is no waterpump. They will make a little boiling sound when they are pulling hard when you shut them off. This is normal. Check to see if there is dirt or chaff on the outside of the radiator and make sure the fan belt is tight enough.

Thanks for sharing the info on the washing soda. I have a 41 BN that I’m just putting back into service after having sat without a radiator for more than 5 years. It didn’t overheat before – but the morning I parked it, it threw a fan blade through the radiator core while I was pulling a one-way. I’d like to flush out the whole cooling system, including the (used) replacement radiator. Maybe I’ll hose out the block first to make sure there aren’t any mouse nests in it!