where is the water going?

[brichter]

Two of my cubs have developed the same problem. When I am mowing in this Godawful heat we are having, the water seems to just go away in both of the motors. One is a lowboy and the other is a standard cub. I fill them up and of course it will spit back when I turn around and I realize this is normal but after about 30 - 45 minutes it is a solid stream of steam so I have to stop and add water. I cannot find a leak in the lines or the radiator. There is never any water showing on the radiator and below it. The oil shows no water. What's going on?

BR

[Clemsonfor]

It's boiling out. There is no pressure on the system. My guess is that the radiator need rodding out and crud flushed out of the system. Have you cleaned out the cooling system before? I'd start by just flushing it, useing a commercial flush before I pulled it down maybe.

[brichter]

I had thought maybe that was the case. I remember seeing some posts on here years ago about taking the hoses off and cleaning the system from that end. I think I will run a search and see what I can find. Thanks

[tst]

the bolster gets full of sludge, the block builds up the crap in the water jacket, pull the lower hose housing off the block and stick a hose in the block to clean it out

[staninlowerAL]

I had thought maybe that was the case. I remember seeing some posts on here years ago about taking the hoses off and cleaning the system from that end. I think I will run a search and see what I can find. Thanks

BR, someone posted that a pressure washer wand inserted into the block from the removed lower water outlet point works good to clean the block. You can also use a piece of metal tubing with a water hose fitting installed to get back to the rear area. Probably have to bend the tubing a little. Stan

[inairam]

recent post on cleaning cooling system viewtopic.php?f=1&t=108090&p=857503#p857503

[mbarcus]

Are you sure the fan belt isn't slipping?

[brichter]

yes, I checked the fan belt

[indy61]

Mine did that a couple weeks ago. I removed the grille and sprayed the radiator with a hose from both sides. It's been fine since but considering using the Lestoil flush.
I wonder if making an adapter to hook up a hose to the bolster drain will help flush debris?

[Glen]

The radiator fins need to be clean, to get good cooling.

Clean the radiator core with a garden hose, with a nozzle, like indy61 said above.
Make water go through the core from the rear, forward.
If there is debris in front of the radiator, remove the grille and clean it out.
Work when the engine is cold is better.

I think you meant you are using just water in the Cubs.
A 50/50 mix of water and antifreeze works better in Summer too. I think it will prevent some of the water evaporation. You can read on the packages how it raises the boiling point of the water.
1 gallon of antifreeze makes close to a 50/50 mix for a Cub cooling system.
A Cub cooling system holds 9 3/4 Quarts, so you need almost 5 Quarts of antifreeze for a 50/50 mix.

If you can't get the engines to run cooler, I suggest waiting until the weather is cooler to use the rotary mowers. It's not good for the engines to overheat them.

[BigBill]

Get a cooling system pressure checker. Don’t pump it up too much.

I have a plan to help it cool off better. Isn’t there a after market coolant pump that goes on the radiator hose to pump the coolant? I think one setup is used for a block heater. Also I have six bladed fans for the int154 I think it fits the fcub too. Now what about a after market 12 volt temp controlled radiator electric fan infront of the radiator?

My PO changed my 52 fcub to 12 volts.