Re: Diesel Truck for hunting
I believe you will find it's the flash point of diesel fuel as compared to gas.
The preheaters on the Dodge heat the fuel and the vehicals with glow plubs heat the cylinders and also the fuel that is being pumped in. Heating the fuel and/or cylinders help the diesels start in cold weather since the flash point of diesel fuel (under pressure or not) is much higher then say a gas engine therefore, heating of the fuel and combustion chamber first, is needed in cold weather.
That's another reason the over the road drivers seldom shut the engines down in cold temps. They may not get them started again if they cool off and a glow plug or two doesn't function correctly.
Your teacher was correct , "if" the engine was gas and had high compression like gas engines do, heating wouldn't be needed in cold temps.
With the flash point being higher in diesel fuel and many times lower compression then a gas engine has, the preheaters and glow plugs are needed to get them started.
If you keep the block heaters plugged in or keep the vehical in a warm garage, no problem at all starting. You don't even have to wait till the warming cycle light goes out.
I think most will find that the flash point of Diesel fuel being higher then it would be for gas engines is the main reason for heating the fuel and chamber "first" in cold temps.
I have a Case backhoe with a diesel. In cold temps that engine won't start at all unless it's heated first. When the temps climb above 30 degrees, it fires right up. Needs glow plugs replaced.