over heating 8n

[Mortyouery]

For some time now my 8n has spit some fluid from the radiator overflow when under heavy load. The radiator is filled properly to just over fins. Last weekend, plowing more ground than I usually take on, she began to steam after an hour or so. I let her rest for an hour, added some water, started plowing again, and fairly quickly she was blowing steam. I let her cool and drained the radiator. Nothing shocking though I think slow to drain. Refilled, went to plow, same problem. I drained again and filled with vinegar. Left for 2 days, drained, again nothing surprising came out. Pretty clean really, but I still think she drains slowly. Refilled, did a little bush hogging and soon overheating/blowing steam. I heard an infrequent "click" which might have come from the water pump. Upper hose was hot, lower not so much. There is not a lot of obvious swirling water in the radiator when you peek in. I thought I had a thermostat in her, but did not feel anything in the upper hose and there is no extra hose clamp. This only happens under heavy load.

Suggestions? I must get sunflowers planted!

 

[JMOR]

I can see plenty of flow looking into my radiator. Might check thermostat.

Specs as I recall are for 16 gallons per minute.......ought to be visible!

Haven't replaced the water pump between the time that this was not a problem and now have you?

 

[QC]

You may have a bad head gasket.

 

[duey]

Since this may be a long term problem, you might be the victim of water pump that has the impeller cast with the fins curving the wrong way... sounds like the classic symptoms.

With the pump removed, and the shaft turned CLOCKWISE as viewed from the front, the vanes should serve to centrifuge the coolant out and away, not "carve the coolant inward".

BUT FIRST:

Your fan belt is tight enough and NOT RUNNING in the bottom of the groove, right? It has gotta run on the sides of the sheave.

Good luck with it duey

 

[Bruce (VA)]

The most common reason for an N to “over heat” is over filling the radiator, but you already know that. (check out tip # 23, below as well as tips 25 & 35) If it was overfilled it was not actually over heating; it is just spewing out the excess water.

If the radiator is not overfilled, check for low coolant, a loose fan belt, debris in the radiator fins or a stuck thermostat. A bad water pump will usually squeak or leak. A head gasket problem usually gives you performance problems. Pull the spark plugs & see if you have one really, really clean...as in steam cleaned! Sometimes, but by no means always, a compression check will show a blown gasket. But, sometimes not.

Lastly, and this just happened to a friend, the radiator might be clogged. After years of running straight tap or well water & infrequent anti-freeze changes. all of that rust & scale settles in the bottom of the radiator.
50 Tips

 

[Jerry/MT]

Make sure that your timing is correct and that the carb mixture is not too lean.
Make sure the fan belt is tight and not slipping. Rev the engine and see if the lower hose collapses at high rpm.
Make sure that you have a properly working pressure cap and it's the correct pressure for your tractor.
You really should be running with a 50/50 antifreeze/water mixture and not straight water and you should have thermostat.

 

[Mortyouery]

Wow...lots of ideas here. I have owned this tractor for 20 years and she's running as well as she ever has (absent over heating). Reviewing all the input, I believe my problem is a clogged radiator. I can pour water in the radiator from a jug, bottom hose off, and fill the radiator with ease and have to wait and watch it slowly drain. Does anyone know how long it should take a healthy/new radiator to drain? Or ounces/gallons per minute coming out the bottom pipe? I am guessing I'm getting 20 oz./minute. "JMOR" indicates the specs call for 16 gallons per minutes from the pump into the radiator! Should I be getting 16 gallons per minute out the bottom pipe? If so, that's my problem. Water pump is "starving" for water.

You guys think so?

 

[Mortyouery]

...thinking about this more, the 16 gallons per minute from the specs are the result of the water pump exerting its pull/push through the system at 1400 rpm. So I am left wondering the gallons/minute that should come thru the radiator on a static basis?