Re: 322 Overheating/Oil Pressure Issue
Drake, As far as overheating, make sure the belly screen, the 3 vents on the pedestal, and the screen behind the radiator are clean. If you have an air compressor, blow the radiator from the engine side. If no compressor, a garden hose will do the same...WHEN THE ENGINE IS COOL !!! If garden hose, try not to get wiring wet!
Another possibility is the thermostat...which you can check. First, get a new gasket/0-ring from JD dealer, T32587, and a thermometer...infrared available at Harbor Freight for about $25. Remove thermostat and place in a pot of water. Heat water and monitor temperature and thermostat. At 160ļF, thermostat should start to open. At 184ļF, it should be fully open. Could also be a loose fan belt...check for tight...or a bad water pump or a partially clogged radiator.
Oil pressure light. Based on your findings, it's NOT an oil pressure problem. Also, if you removed the wire from the sensor and the light stayed on, it's NOT a sensor problem. You have power to the light when the key is "On". The light needs to be connected to ground to illuminate...this is done through the sensor. If light is on when wire is off the sensor, you've got a short in the wire or a bad ignition switch...possibly a bad diode, not sure.
Due you have TM1591? Schematics there will be helpful...as well as other info.
One last comment: A single wire from the ignition switch will turn on the oil pressure light and the coolant temp light. You may have a bad ignition switch! If original, I'd start by replacing that and see where things go from there. Bob