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G-MAN
10-01-2002 10:22:13
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Re: AC in 4030 not cold enough at high rpms? in reply to Richard in IN, 09-30-2002 23:53:14
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Richard, the other posts bring up some very good points. A/C problems are generally pretty easy to fix. First, check the condition of your cab air filter and recirculation filter - over the top of your head in the cab. The cab air filter drops down, and the recirculation filter is located in the black plastic grille with 4 or so screws in it - directly in front of the cab filter housing. If dirty, blow the cab filter out, and you can wash the recirc filter out with water. With the recirc filter out, look at the evaporator and make sure it looks clean. If it's dirty, you'll have to raise the cab roof and remove the airbox cover to blow it out. Also check the condensor/oil cooler for plugging, and the radiator as well. Even if the condensor is clean, the fan is obviously on the other side of the radiator, so air has to be pulled through the radiator also. Also make sure your blower fan is working properly and is flowing sufficient air. If all of these check out, look at the sight glass on the receiever/dryer. It is located on the inside of the LH rear fender. Run the tractor for 10 minutes on max cool to stabilize the system. Look for bubbles in the sight glass. If there are bubbles, add R-12 until the sight glass goes clear and then stop. This method will work on R-12 but not on R-143a, as even a properly charged 134 system can still have bubbles in the sight glass. Also look for streaking in the glass or cloudiness of the refrigerant, as these can point to air or water contaminating the system. It sounds to me like you're under-charged. The expansion valve can flow enough at lower compressor rpms to cool decently, but at higher rpms, you're low-side pressure is dropping too much - possibly into a vacuum. Sorry about the long post, but I wanted to give you a variety of ideas to try.
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