Cub Low Boy overheats

M

MK111

New member
Hi new here. I have a International Cub Lowboy that I use for mowing. I believe it is the last year production with the 6 Volt Positive ground electrical. It over heats when the temp outside is hot when mowing with a Woods 60" mower deck. My question would it help if I installed a radiator fan to help cool? How would you wire up the fan for the 6 volt system? Thanks for help I don't want to ruin the motor.
 
The first step is to make sure it is really overheating. It is normal for thermosyphon systems to spit out a little coolant. As long as the level in the radiator stays above the tops of the tubes you are ok. Adding an additional fan will probably not help as the regular fan is usually adequate. Is the fan shroud still in place? They don't cool well without them.
 
Here is a recent thread on this topic:
http://www.farmallcub.com/phpBB2/viewtopic.php?f=1&t=43075
Review it for comments related to both overheating and flushing the system. Follow the link in that thread to a post on a flushing tool. If you really have an overheating problem, you would be better to spend your time addressing the problem (which probably means cleaning the system) rather than trying to patch around it.
 
MK111,

Welcome to the Cub Forum. I see this is your first post.
The Forum is a great place to gather and share info on/about Cubs.

Jim gives some very good advise. Fix the problem, don't dance around it.
Give the Cub a good flushing and see if that helps.

Good Luck and keep posting.
 
One thing that is always worth checking is your ignition timing. Too much advance will contribute to overheating too, especially if the system is marginal. Flushing the block is important as most Cubs may never have been properly flushed up inside the top of the block where the sediment collects.

Running a 60 inch mower of a hot day is probably the the biggest challenge for a Cub. They can handle it if properly maintained.

And.... welcome to the forum. :D :D
 
Welcome to the forum! As others have said, a good flushing of the block is a great first step. Here's a picture of one I made out of Home Depot stuff and what was on hand for probably under $10. Hook it to a water hose, take off the lower inlet pipe and work it around in the opening over by the starter (shown in the picture below). You'll be surprised at the junk that'll come out of there and the lower part of the radiator.

Good luck,

Dave

flush_tool_1.jpg


water_jacket_port.jpg
 
I have a 154 Lo Boy. I am also having an overheating problem. Last year, I had a radiator leak that was repaired. That was when the overheating started. My symptoms are....losing water through the overflow tube. I have had the radiator checked again, and I have been told the flow is good and no leaks. 8# cap. I have also changed the upper and lower radiator hoses. I can flow water through the block with no restrictions. I still think I have a radiator issue, but not sure. Fan turns at full speed and shroud is in place. Is there anything else I can check or do, or could there be another cause as to why the 8# cap (which is good) releases a ton load of water to the point I need to refill 3 times mowing a 1 acre lot?

Any help here is appreciated.

Thanks.

John
 
jcb209":3jmymtxl said:
I have a 154 Lo Boy. I am also having an overheating problem. Last year, I had a radiator leak that was repaired. That was when the overheating started. My symptoms are....losing water through the overflow tube. I have had the radiator checked again, and I have been told the flow is good and no leaks. 8# cap. I have also changed the upper and lower radiator hoses. I can flow water through the block with no restrictions. I still think I have a radiator issue, but not sure. Fan turns at full speed and shroud is in place. Is there anything else I can check or do, or could there be another cause as to why the 8# cap (which is good) releases a ton load of water to the point I need to refill 3 times mowing a 1 acre lot?

Any help here is appreciated.

Thanks.

John
Click to expand...

John - it really depends on where you are trying to maintain a level in the radiator. Most thermosiphon systems spit out excess until the cold level is just above the top of the radiator tubes. When the water heats and expands the upper tank will be full. If you can, when you think it is time to add water, let the tractor cool completely and see if the level is still above the top of the core tubes. If it is, you do not need to add any more water. If the level has dropped below the tops of the tubes then you do indeed have a cooling problem.
 
The only thing the guys haven't suggested is making sure the fins are not plugged, covering the front of the radiator. I have to blow (air compressor) out radiator 2 or 3 times a mowing season.
 
Bigdog":efez26ls said:
John - it really depends on where you are trying to maintain a level in the radiator. Most thermosiphon systems spit out excess until the cold level is just above the top of the radiator tubes. When the water heats and expands the upper tank will be full. If you can, when you think it is time to add water, let the tractor cool completely and see if the level is still above the top of the core tubes. If it is, you do not need to add any more water. If the level has dropped below the tops of the tubes then you do indeed have a cooling problem.
Click to expand...

Bigdog, it is below the core tubes when i go to refill (after letting the tractor cool down).

Eugene":efez26ls said:
The only thing the guys haven't suggested is making sure the fins are not plugged, covering the front of the radiator. I have to blow (air compressor) out radiator 2 or 3 times a mowing season.
Click to expand...

Eugene, did that plus used a pressure washer to clean the fins. Also removed the front grille. Removing the front grille will just mean cleaning the front of the radiator more often (easier to clean, though).

I'm thinking about having the radiator re-cored with larger tubes to help in the cooling, not sure yet. Trying to eliminate all possibilities before going that route.

Thanks for the replies. Any additional ideas appreaciated.
 
Welcome to the Forum John.
Take a look at the photos above, follow the links and do the same thing. A lot of crud will build up inside the block around the cylinders that will lead to overheating. Also, next time you run the tractor, fill up the radiator to the point that you can see the water. Run the engine and look down into the radiator and look for bubbles. This will indicate a blown head gasket or cracked head.
 
And another thought. Remove the grease and grime from the engine. Probably already done. Just a thought.

Guys have suggested flushing the block and lower radiator housing. If you haven't done this, do so. Crud will build up between and behind the cylinders - you won't be able to see it but it's there. The crud will cause over heating and score the cylinder walls and pistons.

And then, a complete engine tune up.

Neighbor has a 154 and I have a standard Cub. We use them in 100 degree outside temps - no over heating problem.

You might want to set the radiator cap on at the first notch - not fully tightened down. 8 lbs is a lot.
 
Already tuned up. New plugs, points, condenser, etc. Fresh Oil at spring start :) I left the cap loose once and had water spitting out of the cap. That was with the original cap. I'll try that also with the new cap. Since the problem started when the radiator was fixed, I'm still leaning toward it being the problem. This week is going to be nice, so I'm going to try all of your suggestions that I haven't done yet.

Thanks again for the replies. If any other ideas crop up, feel free to let me know.

John
 
Don't over fill the radiator. The coolant expands then finds its own level. The excess goes out the overflow hose. Just fill it above the coolant tubes in the radiator.
Never had any of my three cubs overhead. I run the 60" mower on my 154 on a hot day. The old Ford cars used a similar cooling system. Never a problem.

Causes if your really overheating.
Steam??

Head gasket.
Ignition timing
Leaky radiator
Leaky hoses
Cracked head or block.

To get steam upon overheating something is drastically wrong.

These cubs don't overheat never.
 
Here is something I don't see addressed yet:

What, exactly, makes you think it is overheating?

Is it just coolant running out the overflow? Do you have steam? Loss of power?

Most cases of "overheating" in a Cub or Cub-like tractor are induced by the operator simply overfilling the radiator, and then panicking when the excess coolant begins to blurp out the overflow tube. "OMG, it's overheating!!!!" No, it isn't :P
 
I hope he is NOT still experiencing overheating problems over the last six years, if he is....he's got real problems. :lol:
Bruce.
 
Exactly they don't understand the old cooling systems with no catch bottle. You don't fill the radiator to the top. Coolant expands and the excess runs out the overflow hose.
The coolant in the radiator will seek it's own level. It should be about an inch down from the top of the radiator when cold.

Where's his excess coolant out the overflow hose going?
 
I don't know which is the bigger "crime" here; responding to a six year old post or giving the same advice Bigdog did in the VERY FIRST reply. :D :wink: :lol:
MK111"s last post shows as Oct 22, 2013, not what I call an active member that'll see the replies soon anyways.

Well, I guess he could be a reader not a poster :D If so, HI MK111 :big smile:
 
You must log in or register to reply here.
Back
Top