over-heating Cub

D

Dave #2

Member
Hi, fella's, got some more questions....

Do Cub's have a history of over-heating? I just rebuilt the engine in my father-in-laws 1949 Cub. It runs and sounds great. Before putting the front-end back on the tractor, I ran the engine for about 3-4 hours....I hooked up the garden hose to the cooling water inlet and had a drain hose on the outlet that drained out in the yard. While running this way, the engine only needed a very small flow of water to keep cool, so everything seems find with the engine.

Put the front end and radiator back on & now the engine runs hot. It has a 50/50 antifreeze/water mix in it. I shut the engine down at 212 deg. Up until the point that I rebuilt the engine, I have never seen this Cub run before but Dad has been using it since 1975. I gave him a call to see what he had to say about the over-heating and he said that it has always run hot. He also said that he ran a 50/50 mix when it was cold out but drained the mix every spring and ran 100% water all summer long because of the running hot problem. (The operators manual actually says something about running 100% water during warm weather.) I think he should be able to run 50/50 mix year round.

Asuuming the radiator was clogged, I pulled it off to have it cleaned. The radiator tubes are much cleaner than I expected them to be. I'm still going to have it cleaned but what now? If having the radiator cleaned doesn't help, I'm at a loss. Please help.

Thanks,
Dave #2

PS: It's timed correctly, the oil pressure gauge is off scale high at anything above idle, and the oil pan is about 140 deg.
 
The Cub has a thermosyphon cooling system , and that system relies on temperature differential to circulate the coolant. They wil run hot l;ike that at the top of the radiator, but if you feel the return line at the bottom it will be fairlycool. This is normal. Doesn,t take long at all ot get the outlet at top up to 200 deg. As long as the coolant was mixed before you put it in and kept full when hot it will circulate. If the bottom return tube gets hot, then you have circulation problems.
 
Make sure the fan belt and bearings are in good condition.

The tractor will run cooler with antifreeze than with stright water. Antifreeze does a better job of conducting the heat from the engine to the radiator.
 
My 49 Cub has been running extremely hot since this spring. I took the radiator cap off and rev'd the engine and bubbles came out of the water. I thought I had a blown head gasket, but replacing it did not help. I have since determined I have a cracked head. The new one is ordered.

Since you recently overhauled your engine, you might try re-torquing the head bolts. You may have a slight leak from your new head gasket.

Leon
 
The fan shrould is in place.

The belts are new and properly tensioned.

The fan hub and bearing is in good shape. The fan actually moves a pretty good amount of air but the temperature gauge still tops-out. And the gauge seems to be fairly accurate....with the gauge topped-out, the infared thermometer was reading 220 deg.

The fins on the radiator are in good shape.

The head has been re-torqued twice since it was over-hauled. No bubbles appear at the radiator.

The temperature gauge in the tractor tops out at 212 deg.....well into the "hot" section on the gauge. If 212 deg is normal, then how are you supposed to know when the engine is really over-heating (say 220 - 230 deg) when the gauge is already topped out at 212 deg?

Why does the manual suggest running straight water during warm weather? I would think that a 50/50 mix would be best.

Anything else I can do to get the temperature down? Once it gets dark out, I'm going to try and look in the radiator tubes with a spot light....see if they are clean or not.

Thanks for the replies.
Dave #2
 
One more thing...... I don't know what transfers heat better.....straight water or a 50/50 mix but according to Red Line Oil (redlineoil.com), straight water offers the best heat transfer. Check out their "Water Wetter" product. I've never used it but have read in magazines that it does work. Who knows? Just something to think about. It's cheap....if I can't figure anything else out, maybe I'll try it. But what a pain changing the coolant twice a year.

Dave #2
 
Dave #2":jmgglsz6 said:
One more thing...... I don't know what transfers heat better.....straight water or a 50/50 mix but according to Red Line Oil (redlineoil.com), straight water offers the best heat transfer. Check out their "Water Wetter" product. I've never used it but have read in magazines that it does work. Who knows? Just something to think about. It's cheap....if I can't figure anything else out, maybe I'll try it. But what a pain changing the coolant twice a year.

Dave #2
Click to expand...

Changing the coolant twice a year is the worst thing to do. Each time you add new water you also add a new dose of disolved minerals and oxygen which stay behind when the system is drained. By changing regularly the problem is multiplied. The system needs a good cleaning. Next time you add a 50/50 mix, leave it severly alone!
 
George Willer":3tze08hm said:
Changing the coolant twice a year is the worst thing to do. Each time you add new water you also add a new dose of disolved minerals and oxygen which stay behind when the system is drained. By changing regularly the problem is multiplied. The system needs a good cleaning. Next time you add a 50/50 mix, leave it severly alone!
Click to expand...
It would seem that running pure distilled water might help alleviate that, but it seems silly to me to change the coolant twice a year. I'm planning on running antifreeze in Black Cat when she's back together. If its good enough for modern cars with their high-temp engines year round, its good enough for me.
 
Water alone is better at heat transfer than is the 50/50 mix. But so long as the mixture is not boiling, a temperature of 220 is not alarming. For those who wish to delve into the subject more, water has a greater Specific Heat than does the 50/50 mixture. http://www.challengers101.com/CoolantMix.html Using mixtures other than 50/50 might be tempting, but forgetting to adjust during the winter is almost virtually certain.
 
Remember... even using softened water in place of the water straight from the well merely exchanges one ion for another... a mineral is still there. :( The softener just exchanges sodium ions for the calcium or magnesium ions present in raw well water. It all collects in the radiator tank and engine block. :( Maybe (probably) someone else can explain it better. My last H/S chemistry class was in 1950. We tried.
 
Using a spot light, I just looked through every single tube in the radiator....none of them were plugged and they only have very light surface deposits on them. No deposits at all is best but granted that is almost impossible to acheive. None the less, I'll get it cleaned.

Obviously I would like to run a 50/50 mix year round and I think that should be doable but I really hate seeing the temperature gauge buried high even if other Cubs do the same thing.

Thanks for the replies. And I'm always open for other ideas/opinions.

Dave #2
 
George Willer":e4jxy1jn said:
Remember... even using softened water in place of the water straight from the well merely exchanges one ion for another... a mineral is still there. :( The softener just exchanges sodium ions for the calcium or magnesium ions present in raw well water. It all collects in the radiator tank and engine block. :( Maybe (probably) someone else can explain it better. My last H/S chemistry class was in 1950. We tried.
Click to expand...
That's pretty much it. That's why I recommended distilled water, where through a distillation process of heating and cooling you remove minerals and end up with (if the process is perfect) just H2O. Of course, it is impossible to remove all the minerals and impurities, but you end up with almost none, especially compared to either "hard" or "soft" water.
 
"the temperature gauge in the tractor tops out at 212 degrees" - Cubs did not come with water temp gauges. If you have one, it was added by a previous owner. 212 is not a high enough range for this system. As others have said, the thermo syphon system requires a temperature differential in order to work. Leave plenty of room in the radiator tank for water expansion. As long as the top of the core is covered when cold you should be good to go.
 
Hi Dave,

In my humble opinion, with proper belt tension, an operable fan, & shroud in place, these old radiators usually causes vintage Cub overheating, most of the time.

(1909 - 1927 Model T fords had no water pumps either; in 1928, Ford added water pumps in the Model A's)

Not necessary to have tubes clogged to cause problems.

Some old radiators have a small coating of residue inside tubes, some have coat(s) of paint on exterior metal tubes & fins, both of which impair heat dissipation from tubes and fins -- doesn't take much of either one to make the radiator less efficient -- the originals were built to last, but need cleaning sometimes.

Even though never overheating in 100 plus degrees, mine was leaking slightly a few years ago, so I removed it to have it repaired & cleaned.

After soaking bolts at bottom with Kroil, tapping etc., about 3 radiator bolts sheared off flush with the top of the cast iron bottom.

I welded a washer on the sheared bolts, welded a nut on the washer & removed the 3 bolts.

Cast iron bottom under radiator had about 3-4 cups of wet black dirt -- appears for a few years, some former farmer used dirty ditch water to add water to the radiator.

Anyway, ran hose in water outlet on top of head, & more mud came out of engine at bottom hose -- let water run for about 15 minutes & thought the engine was clean -- but then took hose with faucet closed, kinked hose 180 degrees, turned water "on', released kink all of a sudden to cause a rapid surge of water & much more crud was blasted out of the engine.

If engines without water pumps have mud deposits, mud acts as insulation & stops heat transfer to water -- steam engine boilers on old river boats exploded mainly because of river silt deposits in boilers -- boiler metal got hotter from not being water cooled, & the metal became soft & got weak.

I put my Cub radiator back on with stainless steel bolts with Permatex non-seizing aluminum lubricant, filled with 50/50 -- no problems since -- next owner will not shear rusted bolts.

Just my humble experience with a Cub -- sure there are others.

Hope this helps.

H.L. Chauvin
 
212 degrees would actually be a good temperature for the engine to run at. According to the laws of thermodamics it would take about 941 (memory is dimming) times as much heat to raise the temperature one degree as it took to raise it from 211 to 212 degrees, so the system would be pretty stable. That's for an open system. In other words it will be very difficult for the temperature to rise from that point. A low pressure cap will raise that point a little but isn't recommended for older systems.

Do you know any specifics about when/why the non-standard temp gauge was installed?

Most likely the troublesome deposits, if you have any, would be inside the engine block itself.
 
An issue that has not been addressed is the timing of the cam. If it was off one tooth you might very well have a very hot running engine. I have seen it on the old dodge flathead six.
 
Couple of things come to mind.

1) Flush the block and lower radiator housing. It's going to take more than a garden hose stuck in the radiator. After a good flushing you might try washing soda to remove deposits then flush the block again.

2) Lean carburation.

3) Ignition timing. One tooth off will make a considerable difference - quite a few degrees. I'd have to check my manuals but I think the tooth count is 18/36.
 
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