Both my diesel trucks came with OEM heaters and in really cold weather the heaters helped, especially with the Ford (needed more help.) My Kubota tractor (Grand L-4610HSTC) has no engine heater and always starts OK. In really cold weather (below freezing and on down to about zero F.) I wait until the glow plug indicator lamp on the dash goes out and then I turn the key switch off and right back on to cycle the glow plugs a second time and crank it as soon as the indicator lights go off (the second time.) This seems to help. I also am using multi-viscosity oil rated down to 5W which reduces cranking effort. Thick oil will contribute to difficult starting as will any problems in the starting circuits. A tractor may start with one or more marginal connections in warm weather but in cold weather the battery output is less and the energy requirement to crank is higher. A battery maintainer/trickle charger will help keep the battery topped off and better able to crank a cold engine. These are available at auto parts stores and places like Harbor Freight. I now have several and use them, especially in the winter. I have considerable electronics background and can attest to the fact that the el cheapo (about $7 at HF) works just as well as the $25 name brand I bought when I needed one right away. They do not overcharge and "boil off" your electrolyte. You used to be able to buy battery warmers from places like JC Whitney. They were a flat plate that you put under the battery. A suitable substitute is heater tape like you use to freeze protect plumbing. Wrap the battery with heater tapes ( I prefer the ones with a thermostat molded in) and wrap that with duct tape or similar. You can then wrap the battery with some insulaltion over the top of the heater tape. A warm and fully charged battery will crank way better than a cold battery and may eliminate the need to have a block heater. I spent 3 years at Minot AFB in North Dakota where the winter temps were colder than -40F. every year. Cold weather (Arctic) operations teach you a lot of practical experience regarding starting equipment in cold conditions and the preventitive measures that work. Most of the enlisted men living in the barracks who had cars, took the battery out and took it inside with them to keep it warm and effective enough to start their car in the cold. If you have a battery that allows you to add water and you don't mind having to top it off more often then you can put a stronger charger on it and the charging current will help warm the battery. Don't go crazy, just a few amps will git 'er done. I have even seen a heat pad from a second hand store used to cover a battery and warm it. Dipstick heaters: I have never personally witnessed one that worked well. One I saw was pretty enthusiastic and heated the oil really well but it also scorched the oil in contact with the heater. Tank heaters that "percolate" hot water in the hoses do a good job. Heaters that replace a "freeze" plug heat the oil and block directly and they seem to do a good job (I'd look for one with a thermostat.) There have been heaters that replace the crankcase drain plug but I don't know how well they work. There were heaters that attached magnetically to the pan, block, or wherever a magnet would stick that you wanted heat. Sounds like a good idea but I don't know how well they work. In X-treme conditions I always used a tank type "percolator" heater AND a trickle charger and a battery warmer or removed the battery to a warm location. I always got instant starts. I even drove an MG 1500 roadster in these conditions (for a while) and it started instantly but then cooled off when removed from the garage and would get so cold while running that its performance turned to s--t within 10 min. Reader's Digest version: keep the battery fully charged and warm for better starts in cold conditions. IF that isn't enough add an engine heater. @#$%^&*()_)(*&^%$#$%^&*(---- Pat P.S. Anyone know what to do to be able to make paragraphs? Carriage returns are elliminated and all lmy formatted text is unformatted and run together.