What temperature should I run at ?

[martinrdb]

I bought a new (to me) Deuce but the temperature gauge didn't work. I recently replaced both temperature sensor and gauge and it seems to operate around 140 degrees which seems very low.


The instructions suggest I should not drive until the needle moves from the starting position of 120 degrees - this seems to take 15-20 mins of idle. It then seems to run at about 140 degrees which is less than 1/8th in from the start of the gauge. The book however, suggests the engine runs at 200 degrees (which is center of the gauge).



Granted the book seems to be for earlier Deuces's - mine is 1984 is that makes a difference.



The guys at Saturn Surplus says the engines run colder than you think, but to check in this forum



Is the above correct ?

 

[Desert Rat]

Martin,
Yes, the multifuel does run colder than what most people may think. The ideal operating temperature is between 185* and 200*. It usually takes running down the road for about ten minustes before the engine gets to temp.. Stopping at lights and such reduces the temp. dramatically. The cooling system is too efficient for the engine with intention. Out in the field when the truck is working real hard and real slow the cooling system needs to disipate the heat building up from excessive work. I hope this helps.

 

[cranetruck]

This is a subject that I have touched upon many times, in posts, article(s) and just by verbal discussions.
The control of the cooling is done by one thermostat, which begins to open at about 180 F, it is fully open at 195F.
At idle, the engine will probably never get hot enough to open the T-stat. For low load situations, use the winter cover with the flap closed.
In ambients with the temp below 65 F or so, use the winter cover with the flap open.
When driving on the highway, the temperature will drop when you go downhill, as much as 40 degrees. I have seen it go from 180 to 140 on a 5 mile long interstate down grade.
The deuce really needs a radiator shutter with a thermostatic control. Electric fan(s) is another option.
Personally, I now have a piece of plywood in front of the radiator to keep a reasonable operating temp. see image below. During the Aberdeen trip a couple of weeks ago, the temperature was held at 180 to 190 most of the time. It climbed to 201 during one long uphill grade, which is still just fine. The trip for us was about 800 miles. The engine should be kept at operating temp (about 185) for best performance.

On my gauge, the right temp is when the needle is just to the right of the center.

Straight up and down is 177 F on my gauge.