Living in what temperatures should I start considering an engine block heater?

From what I have seen on this forum it seems like an easy install. Is OEM best or is there a better aftermarket option like a portable unit?

If you vehicle is outside and exposed to below 0* F regularly, it would not hurt to have an engine block heater. You will reduce internal wear that occurs on startup when the oil is very viscous and flowing slowly. Is it necessary for us, no? If you keep good, clean oil will you notice any difference before several hundred thousand miles... probably not. Either way, when starting an engine in that cold of a climate, i'd recommend 30 seconds to 1 minute from start up before you drive away and when you drive do not drive hard for the first few minutes.

Engines with turbochargers are far more sensitive because the turbocharger is usually the very last in the oil path. When I was a turbo engineer at Cummins, it took longer than a minute from startup to for the oil to reach the turbo at -40*F. That's a minute of the turbo running only on residual oil film and remember turbos spin ~10x+ faster than your engine. This was important for customers in extreme cold climate who used the engine as an emergency generator and so it would need to start and produce peak torque within seconds (think a hospital losing power..)

Engine Block Heater Installation on 5th Gen 4Runner - Step by Step

I installed one a couple years ago, mostly out of curiosity. I put a waterproof plug in the front grille, ran the wires nicely, and... it hasn't been super useful for two reasons.

First, I put it on a remote timer and when it's really cold out I have it turn on a couple hours before I know I need the car, mostly hoping I'll get heat & defrost quicker. It doesn't really work for that because it ultimately doesn't put out much heat. I think it's intended more as a "keep warm" feature rather than a "warm up" feature? In any case, starting from cold I don't notice a huge difference in "time to warmth" even if I run it overnight.

Second, it turns out when I really need it I'm usually traveling. I was staying at a hotel in Vermont yesterday and it was -14 when I started the car in the morning. Would have used it, but I was at a hotel...

At the end of the day the 4Runner starts up just fine when it's that cold. I do let it run or a minute before driving, and you can tell it's cold because EVERYTHING is "sticky" - wipers, brakes, heater motor, even the LCD screens look funny. But it all goes away in a couple minutes.

So even though it was cheap and easy, based on how much I use it in New England I wouldn't do it again, and I certainly wouldn't do it in Florida...

This is what the guy that wrote up the install measured (coolant temp before starting engine):



I grew up in Edmonton. Up there many many parking lots have outlets - hospitals, motels, schools, etc. But that's because it gets stinking cold 3 months of the year ... and always had an extension cord in the trunk.

Thanks, moving north is the main reason for my curiosity. It has been in the 30s in Florida, had to break out my ski clothes 😁