At what temps do you plug in your block heater?

[BobsArmory]

So a few weeks ago I picked up a slightly used 2023 GMC Sierra AT4 with a 3 liter Duramax. For this winter ( Michigan) I was thinking of installing an outdoor timer for the factory block heater on the side of my garage and setting it up to turn on about 4 hours before I leave to go to work.

Would 4 hours be enough time?

At what temps would you consider plugging it in?

 

[BrendanC]

IIRC the cord has a thermostat in it set for 0°F

 

[KrisZ]

The his question needs to be asked in January

On a serious note, fours hours is probably not enough for a diesel truck with a large coolant capacity. What’s the wattage on that block heater?

 

[Thermo1223]

Such a newer truck, plugging it in isn't needed til past -5F maybe. Quick heat glow plugs & high pressure fuel you are off to races almost instantly.

 

[Snagglefoot]

It all depends on the ambient temperature. I plug in at -5 F. Usually, I’ll plug it in when I arrive at home, so as a result I get way more than 8 hours on it. This routine lasts for about two weeks during the winter. I run a 0w30 in my 6.0 gas engine. There are 0w40 motor oils available for diesels. Try four hours and see if it works at the temps you experience. You’ll notice the difference. Nice truck!

 

[Snagglefoot]

Here is the 3.0 Duramax Diesel owners manual supplement. It suggests 0w20 Dexos D. You won’t have trouble starting it but I understand why you would want to baby it with a block heater.

 

[Snagglefoot]

And for the thickies out there.....

 

[dfarr67]

I plug in at -25C, for two hours, below -30C three hours. Let idle to warm up 15minute. Drive easy until warmed up.

 

[carviewsonic]

The last GM truck I drove at work and my 2018 Impala both have thermostat's built into the block heater cord that don't allow operation until the temp drops to 0 deg F (check your owner's manual). So 0 deg F and lower - plug it in. I use an outdoor plug in timer for block heaters. 4 hrs to 6 hrs is about right for the block heater to be most effective, without wasting energy.

 

[DriveHard]

I usually only plugged in at 0F and below. I would set my timer for about 4 hours.

 

[ka9mnx]

4 hours is plenty of time. You don't need the entire coolant system warm, just the block.

When I lived in Superior, WI in the 70's/80's we didn't have timers. We plugged in every night after work if it was going to be below 0F.

 

[Thermo1223]

I plug in at -25C, for two hours, below -30C three hours. Let idle to warm up 15minute. Drive easy until warmed up.

Diesels don't really warm up unless worked,15 mins seems excessive.

 

[BobsArmory]

IIRC the cord has a thermostat in it set for 0°F

The thermostat is in the cord, interesting. I would have liked to see it trip at 10f but it is what it is I guess. Makes me wonder if an aftermarket cord would have a thermostat or not.

 

[BobsArmory]

The his question needs to be asked in January

What’s the wattage on that block heater?

It was a slow day at work.
No clue what the wattage is.

 

[tnt_motorsports]

So a few weeks ago I picked up a slightly used 2023 GMC Sierra AT4 with a 3 liter Duramax. For this winter ( Michigan) I was thinking of installing an outdoor timer for the factory block heater on the side of my garage and setting it up to turn on about 4 hours before I leave to go to work.

Would 4 hours be enough time?

At what temps would you consider plugging it in?

View attachment 220222

I think this is personal opinion but I just stopped plugging mine in a couple weeks ago here in Iowa. Why not start with coolant at 130F rather than 50F...

I have mine on a timer that goes from midnight to 6am when I leave. My truck is garage kept. If you are outside it might take all night...

Just my $0.02

 

[CT Rob]

So a few weeks ago I picked up a slightly used 2023 GMC Sierra AT4 with a 3 liter Duramax. For this winter ( Michigan) I was thinking of installing an outdoor timer for the factory block heater on the side of my garage and setting it up to turn on about 4 hours before I leave to go to work.

Would 4 hours be enough time?

At what temps would you consider plugging it in?

View attachment 220222

4 hours is fine. Thats how long i had my timer set for my Ram back when i had it . Though i only plugged it in when it was going to be in the teens or colder.20s-30s no need.It always fired right up no matter what.

 

[Number_35]

Assuming the block heater is appropriately sized for the engine, about 90% of the maximum temperature gain occurs after three hours, and the curve is flat after four hours (that is, there's no further increase in coolant temperature).

 

[BrianF]

I try to consistently do it at -15c and colder. Mostly to take the edge off.

Once I accidentally command started my 3500 at about -30c or a bit colder ambient. It was cold soaked for days and not plugged in. Fired right up after one cycle of the grid heater.

 

[dogememe]

Plug in my what?

But to answer the question I’d say 4 hours is reasonable.

 

[Mickey D]

It was a slow day at work.
No clue what the wattage is.

Block heater is 71 - 120 watts for a duramax.