Block Heater

railguy777 · December 17, 2020

My truck came with a block heater. It was -20 last night here in Ottawa and no more than -15 today so I thought I would plug in the block heater and see how it worked.

I plugged in the heater cord that came with the truck and checked the voltage =120 v. Was curious about how much draw there is but my amp probe showed zero amps

when plugged in. I checked the continuity of the cord, all good. I checked the resistance of the heater at the plug on the truck , it shows open circuit.

I read on other posts about block heaters that the thermostat is in the cord itself. It appears that GM has moved the thermostat into the heater itself on the new models so that

the cord cannot be tampered with. For me I would just like the heater to work when I want it to, not when GM feels its necessary, I think -15 is cold enough to warrant

use of the heater. Attached are pics of the cord that came with the truck -2020 Sierra SLT

redwngr · December 17, 2020

You have a 3.0L (that includes the block heater) or an optional factory block heater on a gasser?

Ottawa area, so working in *C and it was -20*C (-4*F) ?

Was it -20*C when you started it?

How did it start?

Mine hasn't seen temps that low yet.

Salsa De Piña · December 17, 2020

On my 2019 LD, the thermostat is further up the cord, under the hood near the fuse block. Can you chase where the wiring goes in the engine compartment from the outlet in the bumper? Be forewarned that bypassing the thermostat will most likely result in a CEL as there will be a discrepancy between engine sensors on startup. That's why the thermostat was included in the first place.

The bumper plug is probably the biggest feature I'm envious about regarding the T1 because it's a clean look, except I'm concerned it would freeze with road spray or leaving a car wash.

AlaskaErik · December 17, 2020

1 hour ago, Salsa De Piña said:

The bumper plug is probably the biggest feature I'm envious about regarding the T1 because it's a clean look, except I'm concerned it would freeze with road spray or leaving a car wash.

Mine gets all covered up when it's snowing. It should have been placed much higher up to keep as much snow and road spray out of it as possible and to make it easier to reach.

jmer98 · December 17, 2020

Hey Guys Question
I have a 2021 1500 3.0
While driving normal not towing my coolant temp sits about 210 slightly and tends to fluctuate up and down from 210 to about 225. Is this normal I have only 675 mi and has done this from the first drive.
Thanks

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Grover67 · December 17, 2020

Yep normal temps, it'll steady out more you drive it and temps stabilize. There is alot going on and if you get a chance read up on it on why there is fluctuations on how the cooling system works

-Grover67

jmer98 · December 17, 2020

Yep normal temps, it'll steady out more you drive it and temps stabilize. There is alot going on and if you get a chance read up on it on why there is fluctuations on how the cooling system works

-Grover67

Where can I find that information?

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jnissen · December 17, 2020

Search here works well. Read up on engine temperature as there were a lot of posts on it.

jmer98 · December 18, 2020

Thank you very much!

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BigMick2023 · December 18, 2020

My 2020 RST CC has the block heater as an option, have not used it yet.

Will have to give it a try to see if mine does the same.

Is a slick setup with the plug port in front though, just need tp keep the connection cord they provide in a easy to find spot!

railguy777 · December 18, 2020

17 hours ago, redwngr said:

You have a 3.0L (that includes the block heater) or an optional factory block heater on a gasser?

Ottawa area, so working in *C and it was -20*C (-4*F) ?

Was it -20*C when you started it?

How did it start?

Mine hasn't seen temps that low yet.

railguy777 · December 18, 2020

I have the 5.3 .It started ok in that weather just wish I could warm it up before.

I don't like not having the option

YYC-SIERRA · December 18, 2020

Two months ago, I cut a 2" hole in my splash guard under the truck and installed a "NOCO Splitter GCP2 15 Amp 125V AC Port Plug"

The NOCO splitter has two 18" extension cords.

I then bought a quality 3 way outlet (yellow) and secured it up under the bumper, inserted it into one of the NOCO cords.

I installed an 125w Temro heat pad to the oil pan (with build in thermostat), as well as a 100w Besco/Alaska heat pad transmission pan. Also installed a 75w Kats battery blanket. Plugged the 3 of those into the yellow triple outlet. The oil pan heater was a pain because of the grooves in the oil pan, I had to get a narrow 1.5" x 3" pad that just barely fit the confines of the flat section of the oil pan without grooves. Applied a liberal amount of silicone to both pads after installation.

Plugged the factory block heater into the other NOCO extension cord.

So now when I plug my cord from the house into the splash guard, it powers all 4 heaters. The combined wattage does not exceed or trip the 15amp breaker. Slight nuisance to have to get down on 1 knee to plug it in, but everything seems to work great after 2 months.

Edited December 18, 2020 by YYC-SIERRA

YYC-SIERRA · December 18, 2020

More pix.

I've driven in a lot of snow, slush, mud, etc. Both the splash guard and the yellow 3-way under the bumper stay 95% clean and dry, no issues. The NOCO plug has a nice soft rubber plug seal that helps keep any moisture and debris out when driving.

It's clean and hidden. When I change my oil, after I remove the bolts to lower the splash guard, I just reach up and disconnect the 2 NOCO plugs then the whole thing is removed as normal for each oil change.

After a few hours plugged in, I find it raises the temperature on my transmission by approx 10 degrees Celsius. I can only assume the oil pan heater is similar. It definitely starts easier when it's -15 out.

Edited December 18, 2020 by YYC-SIERRA

YYC-SIERRA · December 18, 2020

18 hours ago, railguy777 said:

My truck came with a block heater. It was -20 last night here in Ottawa and no more than -15 today so I thought I would plug in the block heater and see how it worked.

Sorry, forgot the whole reason I came to this thread.

When I did the above installation, I noticed on the cord, hidden away, is a tag attached to it. Says something like "-17 or below" for operation.

I agree with you, I wish it would activate when I choose to plug it in, not when GM decides.