Engine block or oil pan heater?

[Bill Bob]

My tractor has an engine block heater installed as well as an oil pan heater.  Unable to run both at the same time, some say heat the oil for those cold start up days while others say heat the engine block as it will be easier to turn over a warmer engine and be easier on the battery.  For the past several days we have enjoyed morning temperatures from -3 to +7 this am.  What is the recommendation from those in the know?  Tractor is 4 cyl. diesel and 100 HP.

Regards
Bill

[TDKPE]

Nothing authoritative, but all the big diesels I've been around for the last 40 years or so (100-1000 hp) have jacket water heaters. Some have coolant circulators too, especially stand-by generators that automatically start and are put under full load as soon as they're up to speed.

Oil heaters seem to be mostly after-market type units, often with stick-on heating pads. And stay away from dipstick heaters - the surface area is too small for the wattage, so the oil temp can get pretty high right at the dipstick surface.

My Jeep Grand Cherokee diesel has a jacket water heater, from the factory, but they charge several hundred dollars to 'install the heater', which is really just installing the cord, which is only around $15 on Amazon.

[daddo]

I'd say that warm oil will radiate heat upwards and also warm the block internally a little. It's one thing to start an engine and then pump cold syrup, then another to get it started and pump much needed oil. Can you used a synthetic oil to help or use a winter additive?

[Roly]

If the block heater is the type that heats the antifreeze usually the ones that go in a freeze plug I would use that one as the antifreeze would distribute the heat.   It would heat the cylinders which would aid starting.    The magnetic ones are not as good.   All the trucks we had have the water jacket type.    Roly

[Robert Adams]

What Roly said. 

   The stick on pan heaters are very good for transmissions though.

[JGrout]

As one who had to be able to heat engines sitting out in the boondocks with average morning temps 0 to - 40 ( we had machinery that we plowed oilfield roads with) we learned early on that the block style water heating systems worked far better than oil pan heaters. The one time we were darn near stymied was at -60 F but we eventually got the equipment started. We did have a generator to supply power that we started before we left the shop to be sure we had power when we arrived at the machinery  

We even had some tank type heaters that used propane fuel to heat the water. 

they were just as effective as the block heaters

[R Clark]

For what it's worth, when I was stationed in Fairbanks AK 30+ years ago, I had three heating devices on my 1982 Honda Accord:

- Frost plug heater for the water jacket

- Battery blanket

- Interior hot air heater to keep the interior vinyl from cracking

Worked just fine down to -58F.

Conventional wisdom then was that oil pan heaters were inferior to keeping the water jacket warm.  The advantage they had was they were cheap to install and weren't model specific.

[goaliedad]

Can't give any advice as to which type works best, but...make sure to wrap the extension cord you use for power around the steering wheel or door handle that way you won't forget to disconnect it. Don't ask

[A Squared]

Why can't you run both? Running off a generator without enough capacity?

[Stwood_]

Around trucks and equipment since I was young.
Engine block heaters always did the job. Oil heaters, not so much.