CK20 Running hot

[SwedeSpeed]

I recently purchased a used (obviously) 2006 CK20 with 330 hours on it. I bought it to do a variety of jobs, mowing being the most common. To do the mowing I got a 60" Bush Hog finish mower. The trouble I'm having is that after about twenty to thirty minutes of work (mowing fields, 6"-8" grass) the tractor starts to run pretty hot. The gauge gets up to about 1/3 between the middle and the red and stays there. I have checked the coolant and oil levels, they are both fine. The coolant doesn't appear to have any oil in it and the oil appears normal. There are no obvious leaks. I removed and cleaned the radiator screen, removed the battery and cleaned out behind it and cleaned the radiator fins (they weren't that dirty, but, I did it anyway). The tractor continues to run hot. The other day I was using the FEL to scoop out some multi-flora rose bushes and I had the same problem, approx. 20 minutes working, gauge rises about 1/3 of the way between midpoint and the red and stayed there. Any idea what the trouble might be? Thanks in advance for any advice you might have, I appreciate it.

 

[Billrog]

Thermostat maybe, run it at higher rpm, clean the air filter or you may have to flush the system if it's had high calcium water added to it ??

 

[SwedeSpeed]

Forgot to mention that I replaced the air filter. I'm not sure if if it's had high calcium water added to it or not. I ordered a thermostat today and am planning to put that in and change the coolant. Is there a coolant drain in the block somewhere? Also, why would running it at higher RPM help? Just because the fan would run faster? Not saying it wouldn't help, just trying to understand. My knowledge of tractors and diesel engines is very limited.

 

[ritcheyvs]

Cross check the head/coolant temp with another thermometer, maybe a non-contact type. Maybe the indication is bad. Is your fan belt tight? Are the radiator hoses pressurized after the engine cools or are there bubbles in the overflow tank (both bad: possible head/gasket leak). Is the radiator hot at the top hose and cooler (but not cold) at the bottom hose (another use for the thermometer)?

 

[Ranchofla]

Swede, welcome to the forum...

My CK20 runs at the middle point of the temp gauge this time of year when mowing ( I live in north florida). I have had it run higher (more in the range you are talking about) but after cleaning the screen in front of the radiator it dropped down to about the middle. In the fall and spring it runs a bit lower than middle but not by much.

Rancho

 

[mj007]

Swede, welcome to the forum...

My CK20 runs at the middle point of the temp gauge this time of year when mowing ( I live in north florida). I have had it run higher (more in the range you are talking about) but after cleaning the screen in front of the radiator it dropped down to about the middle. In the fall and spring it runs a bit lower than middle but not by much.

Rancho

Ditto - exactly how mine runs

 

[SwedeSpeed]

Cross check the head/coolant temp with another thermometer, maybe a non-contact type. Maybe the indication is bad. Is your fan belt tight? Are the radiator hoses pressurized after the engine cools or are there bubbles in the overflow tank (both bad: possible head/gasket leak). Is the radiator hot at the top hose and cooler (but not cold) at the bottom hose (another use for the thermometer)?

Fan belt seems tight. I will check to see if the hoses stay pressurized, check for bubbles in the tank and check the temps. I'll post what I find this evening. Thanks.

 

[SwedeSpeed]

Thanks, Ranchofla. I tried cleaning the screen and the radiator fins, hasn't made any difference.

 

[SwedeSpeed]

I got the tractor out, did some mowing and got the same results as usual. It gets a little hot and then seems to stabilize at about 1/3 between midpoint and the red. I used a Snap On infrared laser doohickey to measure temps at the thermostat and the block. Readings were between 196 and 206. The higher numbers were on the canister side. Upper radiator hose is not pressurized after cool down and there are no apparent bubbles in the overflow tank (although it did look like there were some fine particles of dust in there, maybe they fell in when I took the cap off? I dunno.)

 

[Billrog]

No bubbles and no oily film that's a good thing.

 

[oldpilgrim]

If you see those temps, you don't have a mechanical problem, you've got a gauge or sending unit issue.

Those temps are showing you're not overheating at all.

 

[SwedeSpeed]

What do you reckon I should do? Replace the gauge, the sending unit or both or just run it the way it is?

 

[gilbertmsg]

I have a 07 and my gauge runs very close to what you are stating. I have no issues with mowing for extended periods at those temps. I have about 800 hrs on my tractor and have learned not to worry.

Eddie

 

[ritcheyvs]

If the indicator doesn't go into the red, I'm not sure you have a problem. The service manual has a table that shows the sensor resistance vs temperature:

60C 153 ohms
80C 74 ohms
90C 55 ohms
110C 30 ohms
120C 24 ohms

If you want to pursue this, you could measure the sensor resistance vs the temp you measure with the IR thermometer.

 

[oldpilgrim]

If you decide you need to fix it, I'd replace the sending unit first. It'll be the easiest piece to replace.

 

[ksbrdmkr]

If the temp stabilizes and you are not boiling water the engine should be ok. If overheating you could probably smell the antifreeze. When mowing with grass seed I stop and clean when the temp is a bit more than half way towards the red and still creeping up. I might worry more about winter operations with not heating up enough.

 

[SwedeSpeed]

Thanks, everybody for your help. I guess I will replace the coolant and the thermostat (probably needs to be done anyway) and go from there. I appreciate all your responses, hopefully I'll learn enough about this machine to be able to return the favor someday.

 

[TJP89]

I don't think you have a problem. You're running a big piece of equipment that is a size bigger than the proper one in the middle of summer. 60" rotary cutter is fine for the CK20, but you're pushing it. I'd expect the tractor to run hot with that kind of load on it. That temp reading is not overheating at all, just running a little hotter than normal, which is to be expected. Keep an eye on it, and if it starts heading up, take action, but if it's stable, it's probably fine.

 

[Coyote machine]

Antifreeze/coolant breaks down over time which is why it needs to be changed periodically. You are running a big hog for that tractor and by replacing/flushing out your cooling system you may find the gauge reads differently. Either way, change out the coolant and flush the system with clean water then refill it with the correct mix of coolant. Keep the radiator and other pre screens and trans cooler fins clean and free of chaff.
Higher RPMs on the engine allow the tractor to run more efficiently and less likely to overheat. Seems counterintuitive, but diesels run cold to begin with and stay within operating temps by running at minimum 1900- 2200 RPMs for a general range. A hog takes a lot of torque/ energy to run effectively, the faster the blades turn the better cutting one gets with less effort. Centripetal force, (of circular motion) keeps the blades cutting effectively and puts less strain on the engine with higher RPMs turning HP power into motion at the blade tips. They don't even have to be sharp necessarily, just spinning enough to beat the grass into submission.

 

[SwedeSpeed]

Just to be clear, I'm running a 60" finish mower, not a brush hog (Bush Hog is the brand name of the mower). According to the owners manual this should not be too big for the tractor. Thanks for the explanation regarding the pto speed. I was thinking higher rpms= more heat, your explanation clears that up.