DB885 temp gauge question

[ScottUSA]

The original gauge set was junk so when rewiring the tractor I used Stewart-Warner gauges. Does anyone know what the actual temperature numbers are at each color change on the factory engine temp gauge? Most importantly, what the temperature is when the needle hits the HOT range on the gauge.

While bush hogging today the temperature was in the mid 90°'s f, the water temp slowly got up to 220°f. Don't know if that is considered overheating but I parked the tractor anyway just to be safe.

[ollek]

When the thermostat opens, the needle will be juts between the yellow and the green field (around 72 to 78 degrees centigrade). When the coolant mixture (50/50%) will boil, the needle will show just between the green and the red field (around 102 to 107 centigrade. All temperatures given for a tractor with a radiator cap that is correct and working as it should. Are you sure that the temperature gauge you ´have fitted works correctly together with the sender on the engine? A new sender, correctly calibrated, has to be fitted if a non original gauge is fitted. If the sender and the gauge are calibrated together by the manufacturer of the parts and you get the temperatures you have stated, then it is overheating. In this case, check that the core is absolutely clean and pay attention to the corners. If overheating still accrues, flush the radiator and the complete cooling system in order to get all dirt out. If in doubt about the correct coolant temperature, measure the temp of the thermostat housing with a infrared laser thermometer.

[ScottUSA]

Gauge and sender were purchased as a matched pair from Stewart-Warner. I have a handheld temperature gauge that is guaranteed within 2% that can be used to quantify the gauge reading at a couple points. Thank you for the gradient numbers for the factory gauge.

I suspect your comments to the radiator core being dirty are correct. Once the growing season is over the engine is due to have the head removed to seek the reason for exhaust valve lash tightening and to repair a leak between the diff and transmission. The block is due for a good flushing and the radiator cleaned with the tanks removed at the same time.