Farmall Cub

My '59 lobby w/mower drinks water!! After mowing for an hour or two it may take a gallon of water to bring it back up to full! I know it would drop some w/the expansion but this is excessive. Have tried to top it off, leave the radiator cap off and look for air bubbles (none ), oil is not turning milky, no wet spots under it when left parked - my only thought is that the leak is so small it is only drawn into the engine when running?? Has good power, runs smooth at all speeds, just likes its water!! What am I missing or what else can I check?? Have not done a compression check yet. Suggestions welcomed! Dusty B

Normal water level is just above the tubes (1/2 inch or so) in the radiator cold. Any more thna that it will spit it out the over flow which runs down to the bolster and out the bottom.

John *.?-!.* cub owner wrote:Normal water level is just above the tubes (1/2 inch or so) in the radiator cold. Any more thna that it will spit it out the over flow which runs down to the bolster and out the bottom.

Way below that John!!

I would suspect a leak around the top hose fitting (they fit notoriously poorly), or in the bolster (my sons leaks there, gets the hand crank wet), or possibly into a cylinder through a bad head gasket. If small enough, that last one could be hard to find. You could try a pressure tester (free from AutoZone, etc), and pull plugs, but it may take a while to show up. Any steam out the exhaust?

Coolant leak is external to the combustion chambers, other wise the plugs would be fouling.

My thought, remove hood and grill, pony tank. Cold engine, top off radiator, look for leaks. Might take hours.

Start engine and let warm up, cover 1/2 of radiator to really warm up engine. Install 7 psi radiator cap. Shut off engine and with flashlight look for leak(s).

I have experience with two kinds of radiator coolant leaks: crack in head at exhaust valve (Super A) and radiator tube rust-through (FCub). The head crack allowed coolant to flash to steam and exit the muffler...this resulted in a noticeable white look to the exhaust. The radiator tube leak occured near the bottom-right corner of the tube bank and was found by parking on a clean and dry surface where the green coolant would form a small puddle on the floor.

The cracked head (Super A) was replaced with a re-manufactured head. This tractor has downward facing valves in the head.

The tube leak in the FCub was addressed by soldering (about three times) then by adding some "stop-leak" to the coolant. One of the soldering attempts was performed by a self-proclaimed expert and resulted in loosing the tube because the fellow used too much heat and burned-through the tube.

Dusty,
Are you using actual water, or antifreeze? The only reason I ask is that I've had a couple of cubs that had pin-hole leaks in the radiator. One, I didn't notice at all when I got it because it had all water in the radiator, but every time I mowed I would have to top off the radiator. It was summer, so I just used the garden hose to fill it up.

Later that summer I did the actual full maintenance on the tractor and drained the radiator and filled with 50-50 antifreeze. As soon as I drained and filled it with antifreeze, every time I ran it I would smell antifreeze. Finally, I found that it was leaking on the engine side of the radiator, about 3/4 way towards the top, and running down the fins towards the bolster. It never leaked enough to leave a puddle on the garage floor, but the bolster would be wet with antifreeze. My guess is that I never noticed it with water because when I ran it to mow, the water would just evaporate off without any noticable odor, but the antifreeze has that distinct smell, and really doesn't evaporate, so once I replaced the water with antifreeze I was able to notice and find the leak.

Bill

Thanks guys - I didn't mention that this is the new Turkish radiator and different head w/new head gasket (Yeah, this is the one I screwed up on and let freeze last winter). Think I w/try the stop leak treatment first - then probably leave a teardown until after mowing season (seems like the way my work schedule goes it might not get repaired between mowing schedule! LOL !) W/let you know how things work out. Dusty B

Hmm, you said it froze last winter? I bet there's more damage than you initially found.

Matt Kirsch wrote:Hmm, you said it froze last winter? I bet there's more damage than you initially found.

Wouldn't there be more evidence if that were the case?? There are no drips, puddles, drop in water level when left standing, nothing in oil - leads me to believe it has to be going out thru the cylinders while running (no air bubbles in radiator tho if filled to top?). For time being just going to keep on trucking and adding water! Thanks for all the suggestions tho. Dusty B

If you are running straight water, put in antifreeze. I know it is hard to let the money drain out, but water, especially when engine is hot will evaporate away much faster than antifreeze, including in oil. Antifreeze will stay put and be more obvious. Unfortunately it is also hard on rod bearings.

We run straight water with a C-3 on one of our LoBoy's. If we run it hard and it is hot outside, we will loose about that much water out the overflow tube. We have a rubber tube for the overflow that sticks out from behind the dogleg and you can see it drip away. A three bladed finish mower can really tax a Cub. --Lee

You could try this, then you could measure how much goes out the overflow and how much you're actually leaking. It's just a hose to the overflow tube and an old bottle for a garden hose fertilizer that happens to have ounces marked on the side. Held on with a piece of twine. I have always overfilled my radiator because I never really knew the proper level. If I fill it to where I see liquid just at the upper neck, it boils out about 12 ounces. I think this is just getting to the proper level, however, on a hot day while mowing for 2 to 3 hours it has boiled out as much as 28 ounces. This is with a 50/50 mix. Hope this may be of some help.