Engine block heater

[Waspswatter]

Would like to get a block heater for a 2010 Silverado. What type/size do I need?

Winter is coming!

[Isaac Zachary]

I prefer the circulating tank heaters. The more powerful, the better, if you don't mind plugging it in an hour or two before you need to go.

If you have a 20A outlet, I'd go for a 2,000W heater. If you only have a 15A outlet then you can't go any higher than 1,500W. But if you plan on leaving it plugged in all night then you'd probably want to go with whatever a stock block heater would put out. For a Silverado, I'm guessing an all night block heater would be around 500 to 750W.

If you go with a high powered circulating tank heater, the Kat's brand (which is usually rebranded as the store brand in any parts store) don't have a one way valve, which could limit cabin heating as some coolant will bypass the heater core as you drive, but your mileage may vary. If you don't get temps well below zero Fahrenheit you're probably fine with a Kat's. However, i understand the Zerostart circulating tank heaters have a valve, but are more expensive.

[Isaac Zachary]

I thought I'd go ahead and explain my reasoning,
I have a 2.5L 4cyl engine. With a 200W OEM cartridge type block heater (goes in hole on side of engine purposely put there for a block heater) I have to plug it in all night for it to really do anything. And in the morning my engine is about 30⁰F to 40⁰F warmer than ambient. If I plug it in for 10 hours it'll use 2kWh of electricity per night, or at 15¢ per kWh, 30¢ per night. Multiply 30¢ by 30 days and that's $9 per month to have the engine only 30⁰F warmer than ambient.

But that 1,500W heater plugged in for an hour will use less electricity and result in a warmer engine. It'll be closer to 80⁰F warmer than ambient in an hour, and only cost $6 of electricity per month.

With the 1,500W heaters, on smaller engines at least, i can actually heat the engine enough to get in the car and have heat immediately for all my body warming and defrosting needs.

Another drawback to the circulating tank heaters, however, is that you don't want to start your engine (or water pump) with it plugged in. I've fried a few that way since the flow is opposite of that of the engine causing it to boil out, dry up and overheat.