Cub overheating uestion

[rob511]

Hello, I'm new to working on these Cubs, have only worked on N and Hundred series Fords, so I apologize in advance for what may seem like simple questions.
This is my first experience with Thermosyphoning systems. I recently acquired a 58 Cub Loboy for what seemed like a great price. After initially using it I noticed quite a lot of water and steam coming from the radiator. So I removed the radiator, cleaned the front bolster, was hardly any gunk in it, flushed the block with the head on and put a new radiator with a no pressure cap on. Started it and ran fine, puked a little anti-freeze. no noticable bubbles in coolant nor any sweet smell coming from the exhaust. While running, the radiator cap is cool and the lower hose is cool as well. After I shut it off, a couple of minutes later there is steam coming from the front of the radiator and from the radiator filler neck area and the radiator cap is too hot to touch. Any ideas, i'm at a loss for the moment. Thanks again.

[PAUL K. in N.H.]

What Type radiator cap is on there ? Should use a non pressure cap.

Paul K in NH

[bob in CT]

When you flushed it, did you remove the cast nipple on the side and get up inside the block?

Follow this thread for the 100% coolant flush method:

http://www.farmallcub.com/phpBB2/viewtopic.php?t=18457

[Bigdog]

Thermosiphon system relies on temperature differential to circulate the water. What you describe sounds pretty much normal. The cub will spit out excess coolant until it is happy with what is left. Usually an inch and a half or more below the bottom of the fill neck. As long as the tops of the radiator tubes are covered by coolant you should be OK.

[Barnyard]

Welcome to the forum. I just want to add that you need to pre-mix your water and coolant since they will not do that if put in separately.

[goldencub]

Bob - regarding the flushing, you said "did you remove the cast nipple on the side and get up inside the block?" I'm not sure what you mean by that. What would I be looking for and on which side. Is it shown on the blow-up of the crankcase with a part number? Thanks Al

[evielboweviel]

right side, up front, low
unbolt from engine block, unhook from rad hose and flush the bottom of the bolster and engine real good. lots of reports of bottom of bolster being full of crud
Ron

[jnr127]

I have some input on this situation, which will probably show how " not so quick" I am. I recently got a f-cub and it also was steaming and overflowing everytime I fired it up. I remembered on this forum talk about the cub finding its own level sometimes for the radiator. Didn't think much of it but it did it everytime I started. I looked at the overflow tube for a minute and noticed the tube was so easy to see, I finally figured out the fan shroud was missing. Put one on and it hasn't over heated since. Guess I couldn't see the tree in the forest. Jon

[bob in CT]

Bob - regarding the flushing, you said "did you remove the cast nipple on the side and get up inside the block?" I'm not sure what you mean by that. What would I be looking for and on which side. Is it shown on the blow-up of the crankcase with a part number? Thanks Al

There is a cast water neck on the right side, like Ron said. It is below the distributor and above the starter. It comes off the block using 2 bolts. I stuck my pressure washer up there and a lot of crud came out. Eugene's hook nozzle is even better.

You can get GSS-1016 Blue Ribbon Service Manual off the manual server or PM me and I'll email it to you. It has a cutaway diagram on the block and shows what needs to be flushed. You may be OK as BD said. The hottest place is in the block when the engine shuts down. The "heat soak" from the iron will heat up that water and it will siphon out. Since the fan is not running the radiator will get hot at the top because that is where the hot water comes in. Since the radiator is cool when you first shut it off, that tells you the system is working properly and the cooling system is able to keep up in operation.

[goldencub]

OK - now I know what you're talking about. The term "Cast water neck" there is little question about. "Nipple" is apt to get me all excited and I tend to lose my focus!!! Thanks Al

[rob511]

Thanks for the quick resonse. I pulled off the lower water manifold when I flushed it. I am using a no pressure cap on the radiator. While the Cub is running, the cap is cool and the lower manifold is almost cold, but after I shut her down the cap gets very hot and I get steam from somewhere. The steam is coming from the hole in the hood where the radiator filler neck comes through. It looks like this has been happening for a while because there is no paint left on the hood in that area. Could the steam be possibly coming from the overflow tube from the radiator. I looked for cracks in the head/block and am unable to find any.

[Don McCombs]

Look for cracks in the solder joint between the radiator filler neck and the overflow tube.

[Eugene]

Something else to check. Check the ignition timing.

The thermosyphon systems, with a fully warmed up engine, operate warm to hot - 180 or more degrees F wouldn't be unusual. When you shut off the engine the coolant keeps circulating but the fan shuts off. This will rapidly warm up the radiator/coolant to block temperature.

You may not have a problem. Could be an over filled cooling system.