The Fordson Tractor Pages Forum

Just a quick question guys. I had the Dexta up and running yesterday just sitting in the garage now that I have the axle and front wheels on her again. Just wanted to hear her running before heading off to Angola for another 4 weeks for all my sins lol. I noticed that she was running quite hot I.E. just above 175 deg F just above the blue band and at the start of the red on the temp gauge. The blue band goes from 150 - 175 deg F on the gauge I have fitted.Once the temp got to just above 175 it sat there and never went any higher. I have replaced the radiator all the hoses,water pump, new thermostat and also have the shroud fitted. When I had the engine stripped all water galleries were cleaned out as well. I have no coolant in her yet and unsure what temp thermostat I fitted. I also noticed that the top hose was hot to touch and the bottom hose was just starting to warm up before I shut her off so the water must have been circulating. No water was coming out of the overflow pipe either when she was running. Is this a normal running temp for the Dextas?? I just dont want to go and cook and damage the engine after all that has been done to her. Appreciate any advice.

Ive done a wee bit of digging and found that the thermostat that I purchased was from Agriline Pt # 5174 which is an 83 C / 181 F thermostat which would make the gauge sit just at the start of the red. I also found Mayhill sell one at 89 C / 192 F. This seems a bit crazy since all the gauges I have looked at have the running temperature i.e. the blue between 150 to 175 F. The thermostat from Mayhill would surely make it run higher in the red on the gauge. Does anyone know of a supplier that I can get a gauge with these temperatures within normal running temp??

Think you have to take a few things into consideration Charlie, none of the thermostats offered are of the same design as the one originally fitted. The original one was designed to shut off the bypass when it opened and divert all the flow to the radiator. The modern types only open and allow water to the top hose, the bypass is left open so water circulates in the block without being directed through the radiator. This will cause the engine to run slightly hotter.

The temperature gauge may not be entirely accurate. In work, just above the blue line would be fine IMHO. Your engine is still tight and will tend to run hotter until run in.

Make sure you do not have any airlocks in the system. I find squeezing the bottom hose as I fill the radiator helps release bubbles of air that have stopped the radiator/block filling correctly.

my repair manual says the thermostat is to be fully open at 199 degrees. It also says it is suppose to have one that blocks off the return like Brian was talking about.

For European conditions the thermostat specs are as follows:

Opening Temperature ... 156 to 165 Degrees F. (68.8 to 73.9 degrees C)
Fully open ... 185 degrees F (85 degrees C)

Thanks for the information Brian and Old Charlie. I didnt realise that the new thermostats supplied are different from the original ones. I did squeeze the bottom hose as I was filling it to dispel any air. She didnt get too hot or boil or throw any water out the overflow. I was just worried that the gauge was sitting above the blue at the start of the red but as you say Brian that should be okay as the gauges arent too accurate and I never thought about the engine being still tight after the rebuild having a bearing on it either. I suppose im maybe being over cautious after spending so much money and time on her and just love my blue machine I didnt want to do any unnecessary harm. Thanks again guys for your help youve set my mind at rest so hopefully sleep easier whilst im away lol.

Ive managed to purchase a 74 degree thermostat from Mayhill and fitted it. Have also put Anti-freeze/coolant in and had her running down the road so as I could flush out the gearbox since the gear oil I drained looked like cream. Put in a mix of 4 litres of paraffin/4 litres of oil. The engine was running a good hour and the temp gauge is now sitting at the lower end of the blue and never moved so all looks good and the gearbox has nice clean oil in now too.

Hi Charlie63

Can you confirm that the thermostats that you have purchased have a giggle/wiggle pin fitted?

The thermostats that I have purchased as suitable for the Dexta, do not have a pin to allow the air below the stat to escape. After a road run I would find that the cooling system had lost a considerable amount of water even though there were no apparent leaks. Eventually I removed the thermostat and found that the engine ran a lot cooler as expected but, at the end of a run the water lost was negligible. Leading me to conclude that air was being trapped in the block until the stat opened and released it.

Gerald

Gerald,
None of the thermostats have the wiggle pin in them. When filling the radiator I squeezed the bottom hose whilst filling and that seemed to dispel any air in the system. After running with the cooler thermostat and rechecking the radiator level it was fine and there didnt seem to be any apparent air locks or loss of coolant.

I have gotten that I drill a couple, maybe three holes 1/8" or so, in all my thermostats, (in the outer part of thermostat) not only to let air out, but just if it sticks you can stop and it will slowly cool off and maybe make, it back home. You can get 168 degree thermostat or so, most diesels operate around 180 degree. Any type thermostat like that is , as in my ford truck, works and you can get any temperature 160 degree on up. I put 168 degree in mine. Found the box and part # D8NN8575AAWG thermostat lists for ford tractors Dexta 957E super dexta 960E ford 2000 up through to 9700 168 degree

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