Overheating Information

   / Overheating Information #1  

LMTC

Veteran Member
Joined
Apr 19, 2002
Messages
2,086
Location
SW Ohio
Tractor
yanmar
This is intended to be a general fyi. Seem to be a lot of posts lately from people having to be overly gentle with their tractors because they are flirting with the red zone. I can only speak to the models and units we have processed, but that covers a lot of ground so here goes. The CLOSEST I have ever known one of our units to come to overheating when all components were in good repair involved a customer making a first mowing in July (i.e. tall stuff) on hills during a period of daytime temps that were consistently upper 90s and one or two broke 100. Also very, very high humidity. How much more can one challenge a cooling system? I am sure this customer kept the screen clean, etc., as he is very attentive to his equipment. The unit would get close to the red zone, but never got there. It had a good clean cooling system, probably the typical 30% blend we try to use in warmer months, and it did not overheat.

And this was before we learned how to thoroughly "summerize" a unit. We recently did some tests with a 2210D, new radiator, water jacket flushed, yada, yada. Ran 30% glycol and water and pulled a 5' rotary cutter into pasture that had not been cut this year. Cut in range 3, gear 2....so we weren't going slow. Cut for an hour, mid-day, temp right at 90, high humidity (70% or so). Radiator temps were in the 160-170* range, head temps 180-190 in various locations, 218 on the hottest part of the block we could find. We then (well after it cooled down completely) drained the coolant, flushed (it was clean) and put in a very specific blend of several products. Went out and did the same thing under conditions that were very similar. Radiator temps ranged from 130-160, and the highest temps on the head and block were 162 and 202 respectively. The single most remarkable fact is that in this second test the top of the radiator was registering app. 160* where water came from the engine, and app. 130* at the bottom hose where it re-entered. This solution was losing app. 30* as it traveled through the radiator.

Three major conclusions to be drawn:
1. if a tractor is showing a tendency to even approach overheating under anything other than extreme operating conditions, there is a problem. Fix it now, or expect more problems later.
2. there are things to be done to significantly improve cooling in the summer, so long as one is willing to make VERY sure the coolant gets drained and replaced with proper antifreeze protection before temps go below freezing.
3. even if you use the typical 30% glycol/water blend, a tractor in good operating condition will likely be just fine under all but the most extreme conditions.

In our experience, the #1 problem contributing INITIALLY (i.e., before you damage your head gasket) to overheating is lack of adequate flow in the radiator. Probably 25% or more of our units get new radiators during processing. Add to that the fact that some processors/refurbishers/pick-your-own-word seem to have a tendency to go heavy on the glycol (probably because the dark color looks good and hides the **** in the crummy radiator, and with this extra burden you have a formula for early and potentially extensive damage to the engine. Remember, glycol doesn't even work unless mixed with water, and pure water dissipates heat better than any blend of glycol, but pure water does not lubricate the pump nor prevent corrosion in the cooling system.
 
   / Overheating Information #2  
Good information.

But what temp is considered overheating?

I have a YM1700 with a new temp gauge I put on.
Here in the Louisiana heat and humidity it will run somewhere between 210 - 230.

Is that too high?
 
   / Overheating Information #3  
Thanks Len! I knew either you or "Tractor Ernie" would come through with some good input.
 
   / Overheating Information #4  
Big thanks LMTC! From the weather conditions you described for the testing, they would tax my cooling system! Again thanks for sharing your knowledge.
 
   / Overheating Information
  • Thread Starter
#5  
vietvet--I'm wayne, not Len. But I've been called worse, so no harm done.;)

meisal...yes, I would expect it to run cooler than that. You probably do not have full flow in the radiator, and/or your coolant is too thick. Do you know what % it is? If not, shame on you....you need to. If you're not worried about freezing reduce it to 20% and add water wetter.
 
   / Overheating Information #6  
This is good info Meisal. I have a YM2000 and bush hogged with it this Saturday with the temp around 97 and the humidity in the mid 70s. It never got above 155*. What I do is to run the 70/30 mix and flush and replace the coolant every year. I don't go any higher because the tractor's kept inside and it dosen't get that cold in SC. I also check the radiator and screen often to make sure I've got the best possible air flow. I also installed a temp gauge so I can be sure what's going on. My experience is that these tractors tend to run on the cool side if the system is operating properly.
 
   / Overheating Information #7  
Great Post Wayne!

There is so much detail in your testing and questions answered applicable to warm weather operation.

Thanks for taking the time to share.

Mark
 
   / Overheating Information #8  
meisal said:
Good information.

But what temp is considered overheating?

I have a YM1700 with a new temp gauge I put on.
Here in the Louisiana heat and humidity it will run somewhere between 210 - 230.

Is that too high?

The OEM temp sending unit on your YM1700 is set to turn on the temp light @ 248 degrees + or - 5.4 degrees and turn it back off when it cools down to 233 degrees + or - 5.4 degrees.

Danny
 
   / Overheating Information #9  
LMTC said:
vietvet--I'm wayne, not Len. But I've been called worse, so no harm done.;)

meisal...yes, I would expect it to run cooler than that. You probably do not have full flow in the radiator, and/or your coolant is too thick. Do you know what % it is? If not, shame on you....you need to. If you're not worried about freezing reduce it to 20% and add water wetter.

Sorry Wayne - my bad! :rolleyes: Len has nothing on you - you're both great!!!
 
   / Overheating Information #10  
Even though I don't own a Yanmar anymore, I want to say THANKS for the information.

Travis R
 
 
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