790 Operating Temperature

[heigar]

The instrument panel on my 790 works intermittently. I want to install a mechanical temp gauge. Does anyone know the maximum operating of the engine?

 

[Whitey]

Have you tried the JD web page?

 

[Willl]

My tech manual says "69.5 - 72.5ｰ C (157 - 163ｰ F)"

 

[heigar]

Thanks for the reply.

 

[RalphVa]

Reware of installing gauges that show exact temperature. The hotter thermostats are set at about 195 F, but you'll likely never see this on a temperature gauge. Never change out a thermostat based on what you see on a gauge. Did it once and saw no change and buggered up the aluminum threads in putting the "stat" back in. Best to leave the beast lie if its working at all. Thermostats either work or they don't, unless something gets caught underneath them that keeps them open. If it works to open and close, doubt it would fail to open at the right temperature. It's a pretty simple device. What's more likely to go bad is the sensor. Had that happen on a 1973 Benz, to the sensor that turned on the auxilliary fan.

My old (1983) Benz runs at 85 C most of the time but runs up to 95-100 C in the summer while running fast in summer heat. Has never overheated to point of boilover. Part of this heat increase is probably due to the timing chaing stretching and decreasing the valve timing about 6 degrees (in 210k miles). I may replace the timing chain this next summer and see what it does to the running temperature and fuel mileage. With antifreeze at about 50/50 mix, think the boiling point is 220 F.

The VW and Tacoma just run at mid point on the gauge. Have no idea what the actual temp is.

Ralph