Cooling System Thermosiphoning

[ScottyG]

Hi everyone,

Just a quick question on how much coolant is acceptable to be losing out of the radiator without getting too concerned about overheating. Everything I've seen on this board indicates that the coolant level should be approximately 1.5" below the neck. That said, every single time I'm mowing, the coolant system is siphoning through well enough but I'm also losing coolant through the overflow. Just the other day, I put about 1/2 gallon of coolant in to bring it back to level. If I don't do this, I can't even touch the coolant that is in the radiator with my fingers.

Part of my lawn is on a terraced slope which makes me think that if I hit the hillside right, this will just promote the overflow action. Maybe in my case, the level should be 3-4" below the neck?

BTW, the tractor runs like a swiss watch and is timed perfectly.

[Arizona Mike]

Scotty, you must have a leak to be adding half a gal. (almost 25%)..does the level hold at 2 qts low?

I changed the coolant in my radiator last week. Good idea to mix the coolant and water together in a bucket before you add to the radiator, as the thermosyphoning won't mix it together.

Keep Henty cool

[ScottyG]

Arizona,

No, no leak. It's all coming out of the overflow, that's for certain. I know because I get hit in the face with it periodically from it being sucked in by the fan. Perhaps my RPMs are too high and I should be mowing a few notches slower?

[Donny M]

Scotty,

Like Mike said make sure all the coolant is premixed before adding it to the tractor. The system will not mix the two. The anti freeze will set at the bottom and will not mix with the water. That means the thermosiphon will not work correctly. I had the same problem as you. I drained the rad and mixed a new batch of brew and refilled to the proper level. No problems now
You should mow at full throttle as per mower instructions.

[Lurker Carl]

Pure water and pure antifreeze have different boiling points unless they are mixed. As goofy as this may seem, it will create a problem!

As far as overheating goes when the coolant isn't to blame, there is not enough air flowing thru the radiator or the coolant is flowing too slowly. The likely culprit is the radiator, crud is clogging it up inside and/or outside. Check the fan, make sure the belt is spinning it and there should be a shroud around it.

[capt jack]

When is the last time you had the radiator rodded ? If all else fails, pull the radiator and have it rodded (also a chance to clean the buckets of mud under the radiator). And every one is correct. Water and coolant dont mix when you don't have a water pump, my '18 T and 30 A Doctor's coupe have the same problem, so I mix it all up and pour it in...good luck

[ScottyG]

Thanks for all the great advice guys. When I had Henry apart last year, I flushed the radiator out pretty good by disassembling it and hosing it out. I also flushed out the coolant system in the engine too. I inspected the cooling fins on the rad as well and did not see any problems. New fan felt and the fan spins fine.

Before refilling, I also premixed the antifreeze and water and the only time that I really have ever separated the two was when I just brought the rad back up to level by adding a 1/2 gal of water. This was after I've been having a problem. I do know that when I refilled after refurbishing, I used old antifreeze. Not used antifreeze, mind you, just an opened container that had been in my garage for several years. I don't know if this has anything to do with the problem but it could be a lead.

Maybe I'll just take all of your suggetions and "mix a batch of new brew". It can't hurt right? 50:50?

[George Willer]

I use a 50-50 mix in everything, as I'm sure most of you do... even in the southern tropics. I use the last empty jug and add 1/2 the contents of the next jug and then fill both with water. I mark the jugs 50-50 so I'll know it's diluted. Then it doesn't matter how much I use to top off a system... it's always mixed thoroughly to the right proportions.

Just a refresher of what you already knew!