i have a 70's JD diesel utility tractor and if it gets into the 40's forget about starting the thing. came from the factory with no glow plugs, do not know what the engineers were thinking but for cold weather it has an ether injection system which i refuse to use, once you start using either i think they become addicted to it and next thing you know you will be gassing it in the summer. i found the easiest thing for me was a heater on the lower radiator hose.
http://www.ebay.com/itm/LOWER-COOLAN...item1c21ff48ab
i can go out there when it is zero and plug it in for an hour and it fires right up,i can tell you that it warms the block almost as well as a block heater and 2 hose clamps to replace it.
just thought i would mention it for any one as an alternative to a block heater
