1970 ish keeps overheating.
- Thread starter Jeffery
- Start date
The high 80s is not a problem. What are the symptoms you are seeing? Have you taken temperature readings? like maybe with a temperature gun of the upper tank or next to the radiator hoses? Is it physically boiling, as in steam blowing out? Is it pushing (liquid) coolant out of the overflow tube? If coolant is coming out of the overflow, can you quantify it?
Don McCombs
501 Club
I think Jim means how much coolant are you losing during a mowing session. The Cub cooling system is a non-pressurized thermosyphon type system. No water pump. Your gasket failures were likely caused by some other reason.
Is it blowing out the radiator itself or the overflow tube that runs from the cap to the bottom of the radiator?
Don McCombs
501 Club
Is it really “blowing” out or just leaking out? Many things could cause a leak. Bill has mentioned two. One or more of the tubes could have a pinhole, allowing coolant to flow down and accumulate at the outside bottom of the radiator. The radiator could be overfilled and running out the overflow at the neck, down the core and accumulating at the bottom. Improper installation of the radiator. The coolant should be no higher than the top of the rounded baffle when cold. Did you clean up the lower casting thoroughly before installing the gasket and radiator, removing all rust, corrosion and remaining pieces of the old gasket? Did you use a gasket sealer on both sides of the gasket when installed? Did you overtorque the radiator bolts caused the gasket to warp or pucker? Is the leak coming from the upper hose or hose connection due to a deteriorated hose or loose hose clamp? Check all these things and let us know what you find.
If you have a pressure cap and suspect too much pressure, leave the cap loose. If a pressure cap is just turned on to the first notch, it will release any pressure as it builds up.
No it literally blew water and steam 3 foot out from blowing gasket on bottom of radiator. I was filling it too far up is what I gathered from the comments I've received. I appreciate all the help! I will let yall know if having less coolant stops the issue! Again thank you all!
That really sounds like a pressure cap that isn't releasing excess pressure. I don't know what pressure the pressure caps were supposed to hold. I think they were quite low. Replacement caps now come in a wide variety of pressures and all claim to fit. I still think leaving the cap loose is worth trying. Not leaving expansion room in the radiator would cause the pressure to rise sharply as the engine warms up.
This is all assuming the radiator/gasket installation fit together well (as in the comments in #10 above). One thing Don didn't mention is that quite a few of the lower castings have been freeze damaged. Sometimes they are repaired and reused but end up with an uneven gasket surface that prevents a good fit of the radiator. I don't mind a phone call but will hold off until you have had a chance to check on the newer suggestions.
Hi,
Cubs came standard with a non pressure radiator cap, up to Cub serial number 248125, TM Tractor Parts listings for new caps say.
The Cub radiator shouldn't build up any pressure with the non pressure cap, unless the overflow is plugged.
The pressure radiator cap was extra, it is a 7 lb pressure cap, their listings say.
There are 2 pressure caps, the filler necks can be different lengths, the listings say.
Here are their listings below, you can look at the pictures.
https://www.tmtractor.com/new/co/1642fp.htm
https://www.tmtractor.com/new/co/2537fp.htm
https://www.tmtractor.com/new/co/3146fp.htm
Jim mentioned the radiator lower tanks damaged from freezing, I would check the casting surface with a long straight edge when the radiator is off, to be sure it is flat.
You could check the radiator bottom surface too.
They have said on here to use a non hardening sealer on the radiator bottom gasket, when putting it together.
Permatex Aviation Form A Gasket works well, people have said. They sell it at NAPA.
It comes in a small can with a brush under the cap. I would stir it well before using it, it can settle in the can sitting.
Cubs came standard with a non pressure radiator cap, up to Cub serial number 248125, TM Tractor Parts listings for new caps say.
The Cub radiator shouldn't build up any pressure with the non pressure cap, unless the overflow is plugged.
The pressure radiator cap was extra, it is a 7 lb pressure cap, their listings say.
There are 2 pressure caps, the filler necks can be different lengths, the listings say.
Here are their listings below, you can look at the pictures.
https://www.tmtractor.com/new/co/1642fp.htm
https://www.tmtractor.com/new/co/2537fp.htm
https://www.tmtractor.com/new/co/3146fp.htm
Jim mentioned the radiator lower tanks damaged from freezing, I would check the casting surface with a long straight edge when the radiator is off, to be sure it is flat.
You could check the radiator bottom surface too.
They have said on here to use a non hardening sealer on the radiator bottom gasket, when putting it together.
Permatex Aviation Form A Gasket works well, people have said. They sell it at NAPA.
It comes in a small can with a brush under the cap. I would stir it well before using it, it can settle in the can sitting.
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