Block heater question - temp? time?

[Johnny248]

Hey guys,

In a gasoline engine, at what temperature would a block heater be a good option in a gasoline engine? Is there a general amount of time one would normally start it at before driving in the morning, or is it something you leave plugged in over night?

I live the SE Michigan. It gets cold in the winter, but not -40 or anything like that. A friend of mine gave me an OEM block heater that he purchased for his truck, but traded in before he installed it. Is it something worth having here? I've never owned a vehicle with a block heater.

Thanks

 

[SC Maintenance]

What kind of block heater - OEM type in the water jacket - or one of the stick on types?

How many watts?

When I was a kid on the Great Plains they were only like 300W and people just left them plugged in all the time. However cars didn't start as well back then.

Assuming its something like OEM I would put it on a timer maybe 3 to 4 hours before you want to start?

 

[WobblyElvis]

It has several benefits but it is unpleasant work plugging it in and remembering to up plug it. Snow/ice can get into the plug.
Heat sooner in the cab, less fuel consumption, less engine wear, drive off sooner....

 

[Danno]

I think block heaters are a good option to have. You will need to get it installed if it's the freeze plug type, which can get pricey.
On a timer for 4 hours, anytime it's expected to be under 10F overnight is a good place to start imo.
I'm a fan of the oil pan heaters. Blocj heaters only heat the water jacket and on one side of the engine. A 250Watt oil pan heater, heats the oil and then heat travels upward.

 

[fantastic]

Not sure how gasoline engines like to do it but they make some oil pan heaters. Not certain how you could heat up the antifreeze unless your engine has a provision for a heating rod. I suppose it would also depend on grade of oil & how good your battery is as well. I would say anything below 0F (-18c) is quite cold. Doesn't sound like you garage it?

The Diesel F-350 is a different animal and 20F is cold enough for plugging in.

 

[Johnny248]

What kind of block heater - OEM type in the water jacket - or one of the stick on types?

How many watts?

When I was a kid on the Great Plains they were only like 300W and people just left them plugged in all the time. However cars didn't start as well back then.

Assuming its something like OEM I would put it on a timer maybe 3 to 4 hours before you want to start?

lol good question. It is a Toyota part, and looks like this one I just snagged a pic from on Amazon.

 

[D60]

I'd also say four hours. They work slowly like a CrockPot on low.

My wife's '08 F150 had a factory block heater and it was nice for her to get heat sooner.

If you park outside, the windshield won't usually ice up at the wipers (Great Lakes may be different) because just enough heat oozes out of the defrost vents. Quite often the entire windshield won't need scraping at all (again, we get snow but the air is DRY) because the snow won't stick to the windshield

Honestly I think anytime you expect night time temps under 40F it's not unreasonable to use the heater. Some of it depends on your willingness to plug/unplug (I drape the cord over the driver side mirror) and concerns about electric bill.

 

[SC Maintenance]

lol good question. It is a Toyota part, and looks like this one I just snagged a pic from on Amazon.


View attachment 310760

Cool, that looks like industrial temperature sensor you would stick in a thermowell. I guess the thermowell is already installed? That should make it easy?

It will be slower but you won't have to worry about it leaking.

Does it indicate watts or amps anywhere?

 

[Johnny248]

Cool, that looks like industrial temperature sensor you would stick in a thermowell. I guess the thermowell is already installed? That should make it easy?

It will be slower but you won't have to worry about it leaking.

Does it indicate watts or amps anywhere?

Quick google search looks like it just slides into and locks into a hole that is in the back of the engine above the bell housing. I'm not exactly sure what it is heating.

 

[B1974]

I plug in my block heater at around -15 Celsius (5 Fahrenheit). You can leave it plugged in all night if you like but it should also work if plugged in about 3 hours before you plan on using your vehicle, depending on how cold it is outside.

That looks like a Cartridge style block heater that plugs into the engine block but not in the coolant passages of the block. Should be a easier install then the frost plug coolant style block heater but you may need to disconnect and move some things out of the way to access it's installation point.

Oil pan heaters are a great idea as well and I use mine on my F150 along with the block heater when the temp is bellow -25C (-14F), but I'm not too sure about using them on plastic oil pans that are more common on newer vehicles. I only plug in the oil pan heater for 2 hours and leave the block heater plugged in all night at those temps.

 

[Danno]

Oil pan heaters are a great idea as well and I use mine on my F150 along with the block heater when the temp is bellow -25C (-14F), but I'm not too sure about using them on plastic oil pans that are more common on newer vehicles. I only plug in the oil pan heater for 2 hours and leave the block heater plugged in all night at those temps.

It is called Winterpeg for good reason.

 

[D60]

The Pentastars also use a weird heater that just goes in a hole but doesn't touch coolant.

 

[ecotourist]

I used to plug in the block hater at anything below about -15F. I left it plugged in all night (partly because I could be called out at any time).

The big trick is to remember to unplug it. It wasn't that rare to see someone driving down the street dragging an extension cord, or as my mechanic used to say "it seems they got a quick start this morning".

Once I had a garage I never had to plug in the block heater. It was warmer in a garage if at least one wall was attached to the house but by driving one or both cars daily, it never got very cold in the garage, not even in very cold weather.

 

[B1974]

The big trick is to remember to unplug it. It wasn't that rare to see someone driving down the street dragging an extension cord, or as my mechanic used to say "it seems they got a quick start this morning".

We call this the Manitoba Winter road snake migration season. Not uncommon to find lost extension cords on the roads and in parking lots during the winter around here.

 

[Number_35]

We call this the Manitoba Winter road snake migration season. Not uncommon to find lost extension cords on the roads and in parking lots during the winter around here.

My company encouraged us to walk completely around the vehicle, looking for a low tire, obstruction behind the wheels, fluid on the ground, etc.

Those who did so did not drive away with extension cords dragging on the ground.

 

[Number_35]

When a block heater is used, coolant temperature follows an increasing exponential decay curve. That is, temperature increases rapidly early on, but the rate of increase slows down, and the temperature levels off.

End of 1st hour - approximately 50% of final temperature is achieved

End of 3rd hour - approximately 90% of final temperature is achieved

End of 4th hour - 100% of final temperature is achieved

Bottom line: Some time on the block heater, even 20 minutes, can help significantly.

Per the Scangauge, if the coolant starts at around -20°C, three hours on the block heater will take it up to around +20°C.

 

[andrew_j]

Personally I don’t think the install time and hassle of plugging in before is worth it for rare extra cold event.

I have started cars at -25F and they started.

 

[hemitom]

I remember one Christmas morning in the early 1970's it was around 35 degrees below zero ! my dad said I better go out and plug the car in or it will never start .
vehicle in question was a 1966 Plymouth fury with a 318 in it and had two block heaters one on each bank.
So he comes in says its so cold the antifreeze was slush in the rad so he plugged it in and put a charger on the battery and said to my mother in two hours we will pack the boys up and take off , sure enough it fired right up and off we went .
Block heater definitely has advantages in cold weather , saves fuel , faster heater, save's some wear on the engine and starter and piece of mind that car is mostly likely going to start when needed.

 

[Number_35]

I remember one Christmas morning in the early 1970's it was around 35 degrees below zero ! my dad said I better go out and plug the car in or it will never start .
vehicle in question was a 1966 Plymouth fury with a 318 in it and had two block heaters one on each bank.
So he comes in says its so cold the antifreeze was slush in the rad so he plugged it in and put a charger on the battery and said to my mother in two hours we will pack the boys up and take off , sure enough it fired right up and off we went .
Block heater definitely has advantages in cold weather , saves fuel , faster heater, save's some wear on the engine and starter and piece of mind that car is mostly likely going to start when needed.

Dad's '67 Newport with the 383 also had two block heaters. This was in Alberta.

 

[dfarr67]

I start plugging in below -15C for about 2 hrs, I also have oil pan heater and trickle charger- I feel it's important to get the starting rpm up with efi rather than lugging the starter.