Block Heater How does it work?

I’ve had trucks that had a circulating block heater that is spliced into heater line . I found truck started very easy in minus 35 weather compared to the actual block heater .. nowadays I just fired up my webasto engine heater which warms engine coolant in a hour enough that your temp gauge starts showing temperature faster..ps when I had a APU boss would tell me to set cab temperature around around 40 degrees and leave it on cycle for the two days I was at home . It was safer then hoping it would fire up in minus 40 weather..

 

In Alaska we use all types,block coolant heaters,circulating heaters,oil heaters and heat pads.Ive seen the circulating heaters burn up a few cars and pickups.
The block coolant heaters are the best,no moving parts,you may have to change the power cord going to it every few years.
The oil heaters go into a fitting in the oil pan.The KW dealer said you only need to use the oil heater for 2 hours so it's best to pur a timer on the circuit,have it come on 2 hours before you want to start.

 

Beats building a charcoal fire underneath the oil pan. I’ve heard stories of that from old timers. Way back when.

 

I took lessons from my uncles who used to use build small fires under their model Ts when it was very cold out, if you know how a T works, you would understand. One used the gas light system to heat the bottom of the engine - his was a 1912.

So I had to use a fire pot with kerosene and rags to get a truck going in North Dakota in the middle of the winter. My kid and I went to recover the truck and it was left unatteneded in -30 weather for a week while the driver was sick and flew home. it took 10 hours to heat the truck and thaw it all out enough to get it running. The batteries were amazingly not frozen but low so it took almost as much time to slowly charge them so they wouldn't explode.

 

Thunder Parts Original HOTSTART Engine Heater TPS151GT10-000 - Coolant preheater | 1500 watts 120V 12.5A https://a.co/d/g9zMWop

A thought, splice into shutoff lines for bunk heat.

 

A standard block heater will heat the oil somewhat, just due to heat transfer from the coolant to the block, to the oil.

I stay mostly in the south in the winter, so I rarely ever plug in. On older diesels it was almost a must to plug it in below 40 deg, but modern diesels with good batteries usually have no trouble starting below 20 deg without being plugged in. It is better on any engine to be plugged in when below freezing.

 

You're old if ya ever used one of these. Lol

 

Now, is it still all right to start it with oil so dense?
I mean, when temps drop to below 10 and the batteries are all right to crank it but even if it starts, is it not wearing the material exponentially?

 

Not reqlly, yes kind of, but theres a film of oil on the bearings and that wont dissapear in the couple of seconds before it gets oil moving, if you have a mechanical gauge on oil pressure, its not instantaneous oil pressure even in the summer

Edit to add, at say -40 it might cause an issue but,fuel gel is a bigger problem then

 

IMO the best combo is a block heater and trickle charger. Use heavy duty extension cord so you warming the engine and not just the ground your extension cord is laying on.