8 replies to this topic

[shupedan]

I have a 1086 IH Tractor that the air conditioner doesn't work properly. If the temperature is 90 or above outside it works fine, but any outside temperature cooler the high pressure light turns on and it stops working. Any ideas on what the problem is? ( Leak in AC coolant, over-charged, ???)

[8gross]

Could be over-charged or a leak somewhere. I had the same problem on my 1086. The a/c would quit working even though there was enough pressure in the system. If you're in a bind and need it to work then run a jumper wire off the headlights to the compressor clutch. Somewhere in that system is a sensor that measures the amount of product in the system. That could be where the problem is coming from. I've had to replace that on a different tractor and swather. If you don't like to spend the money on freon then propane works just as good.

[mlappin]

Well, other than the fact propane is a wee bit explosive. Is the light strictly a high pressure light or is it a generic AC light? Check and see if your condenser is freezing up at cooler temperatures. Could be a bad thermostat. If it's a generic AC light maybe you're a touch low on freon and the higher out door temperature causes the system to run at a higher pressure. I kinda doubt it could be low freon though if it works just fine above 90 degrees.

[Toyes Hill Angus]

Speaking for all mechanics everywhere, please don't use propane! It never seems to blow up, or make a flame thrower to the guy that charges the system with it, just the poor unknowing sap working on it. I've never seen it myself, but it there is a leak on the high pressure side and you are fooling around in there with an incandescant trouble ligh, evidentally it makes for quite a show!
Aside from that if your tractor does catch fire someday (in happens, and nobody plans for it), you have just provided a high pressure hydrocarbon injection system - can you say "adding fuel to the fire."

[Farmineer]

I have a couple things that might seem basic but easily overlooked to check and will affect cooling

Check to see if the evaporator is freezing up, the evaporator is the one in the cab by the fan. Also, check to see that the sensing wire from the thermostatic switch- the one in the cab by the fan switch- is stuck into the evaporator through all the cooling coils. While you are at it make sure it-the sensing wire- is not cracked where all the gas escaped. If you park it, is there a puddle of water under the evaporator tray drain lines? If there is, it likely came from ice on the evaporator. Is the evaporator matted over with crud? Keep the windows closed if the fan is running and you are recirculating cab air.

[Iowa hay guy]

that light is a generic light for high or low i would get out the gauges and see for yourself
also are you using replacement 12 or is it a 134 conversion
from what your daying i would guess its low on stuff our 986 does the same thing

[8gross]

We've got a licensed mechanic that does all of our work we won't touch. Maybe it's due to the area or the equipment we operate. But if the systems leak out over winter storage then I'll use something a little bit cheaper than than topping up with freon every year. My iron is as old as the hills.

[mlappin]

From personal experience the drop in replacements for R-12 usually are more trouble than their worth. I've had two compressors lock up with two weeks of using a drop in and the "special" oil additive. Drain it, flush all the lines and replace with proper oil for R-134A, I've yet to have to change anything other than oil and the freon when converting. If it was low on coolant, it should work barely at all when in the 90's, but you could very possibly freezing up your evaporator if the thermostat probe is not in the fins or you could have a bad thermostat. From my experience as well, if your tractor still uses the a tecumseh or a york piston style compressor, first time it goes out convert it to a rotary style pump. I've yet to have a rotary go out and after changing out three piston style ones won't waste my time or 134A on a system unless we upgrade to the rotary.

[mlappin]

We've got a licensed mechanic that does all of our work we won't touch. Maybe it's due to the area or the equipment we operate. But if the systems leak out over winter storage then I'll use something a little bit cheaper than than topping up with freon every year. My iron is as old as the hills.

Before parking it when your done, pressure wash and degrease everything to do with the AC, look for the oily spots next spring, that's the leak. Not to brag, but before I learned to fix AC myself, we paid the local garage twice to "FIX" the AC in our MF 4880, still leaked when they were done, paid the local Agco dealer at least twice as well to "FIX" it, still leaked, did it myself and went two years then only needed half a pound to get it full. Found a faulty o-ring in the quick disconnect at the cab, for about 10 bucks I just went ahead and replaced all the o-rings in the entire system.