Put a new radiator in my 1990 22RE a few months ago. Been driving around a bit this spring. Engine temp trends to hotter every now and again, especailly up longer hills. Thinking of going back to my OEM radiator, which I had rewelded and painted. Was thinking it might also be the fan clutch. Anything else it could be? Before I take it apart? Engine, thermostat, water pump, all have less than 5,000kms on them.