After an hour of bush hogging with a batwing mower OR bailing hay (anything with the pto), my hydraulic oil temp creeps up to over 156F (as measured at the sight glass and oil cooler with IR gun) and eventually the stop light on the tractor comes on.
- Changed Hydraulic oil and filter
- Ensured coolant is topped off at max fill
- Removed output hose from cooler to and made sure oil is flowing out
- Made sure rocker arms are not up
- Confirmed oil level is between the lines on the sight glass
- Made sure the engine radiator and fuel cooler are normal temps. Hydraulic cooler is the only one hot
- Confirmed with JD that there is no sump filter that could be clogged. Its only filtered by the hyd. filter
- Attempted to bleed air from the cooler but not sure how to do that since the input and output are on the bottom.
- Used only hyguard oil and filter
- Cleaned the cone-shaped caps on the tractor(I don't know what they are called) where hydralic cylinders get locked in place. LIke a float valve. They were pretty cruddy inside.
- Washed all coolers (radiator, oil, fuel) thoroughly
- Cleaned air filters
OTHER INFO OF INTEREST:
Oil temp on the right side of the oil cooler seems to be the same temp as the left side (outgoing) as measured on the main tube. Shouldn't it be cooler? Also, the small tubes on the oil cooler are 138 (I assume these tubes are for the coolant to pass through?).
When the PTO is engaged and the engine is revved, some oil dribbles in from the top of the sight glass and it has air bubbles. Eventually makes the sight glass a little cloudy from the bubbles. After stopping, they clear within 10 min.
ONLY REMAINING GUESSES:
- Clogged oil cooler? How would I know? Could it be after only 900 hours? Can the IR gun tell me?
- Air bubbles in hydraulic oil not normal and causing the overheating or accumulate in the cooler until it is turned off
- Internal hydraulic leak (how would I know?)
- Open the bleed valve on the radiator while running? Not sure how that can help.
- Check to make sure filler cap vents are clean