Engine Block heater working
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Trailering
Joined: Jul 2016
Posts: 23
Likes: 9
From: New Orleans, LA
Engine Block heater working
How can you tell if the engine block heater is working? My 24XLT came with one even though I live in New Orleans area. Well, if you watched the news lately, you saw what we were hit with. So, while stuck at home, I decided to experiment. I plugged in my heater expecting the snow to melt off the hood of the truck after a few hours. Nothing. I unplugged and started the truck to let it warm up. It was mid 20s but the truck started as easy as it does in warm weather. I noted the water temp gauge read 80-ish. I assumed that this meant the block heater did its job. But, I'm not sure. Can someone with more experience with the heater give a couple things to look for in case I ever need to use the heater again???? Thanks.
Mountain Pass
Joined: Dec 2024
Posts: 202
Likes: 110
I'm pretty sure my coolant always says 86 when starting like it's the lowest it reports, but with the block heater I get around 89-93. I could be wrong, I'll check tomorrow morning as I am running trickle chargers with the cord so will not have it plugged in.
I have it on a metered plug and it runs 100% without stopping at approx 900w the whole 3 hours I have the plug active.
It does start instantly, no short delay on the glow plugs and the cab is warming up within half a mile. Supplemental helps there though.
I have it on a metered plug and it runs 100% without stopping at approx 900w the whole 3 hours I have the plug active.
It does start instantly, no short delay on the glow plugs and the cab is warming up within half a mile. Supplemental helps there though.
Cargo Master
Joined: Mar 2021
Posts: 2,044
Likes: 1,336
My truck reads well below 80° coolant temp when starting on cold days.
If he’s coming out in 20° weather and his coolant temp is 90° then I’d say it’s working. But then again, maybe we can get some more numbers from people who use the engine block heater and see their numbers too.
If he’s coming out in 20° weather and his coolant temp is 90° then I’d say it’s working. But then again, maybe we can get some more numbers from people who use the engine block heater and see their numbers too.
Fleet Mechanic
Joined: Dec 2016
Posts: 1,817
Likes: 544
From: Florida
I've had the block heaters on my previous 6.2 and the current 7.3 gassers, but I haven't used them much. However, I used the block heater on my 2004 5.9 Cummins extensively. For starters, a few seconds after plug-in, I could always hear a faint gurgle in the block as the antifreeze began to warm up. Almost sounds like a Keurig warming up. Similar principle. Second, while I never saw it melt snow or ice off the hood, it did a great job on the windshield. Many mornings I walked out to see a nice half-moon of clear windshield extending from the cowl.
Again, not saying this behavior extends to your 6.7, nor am I trying to compare apples and oranges, but a block heater is a block heater is a block heater too. It's simply heating antifreeze within the block.
Again, not saying this behavior extends to your 6.7, nor am I trying to compare apples and oranges, but a block heater is a block heater is a block heater too. It's simply heating antifreeze within the block.
Mountain Pass
Joined: Dec 2024
Posts: 202
Likes: 110
My truck reads well below 80° coolant temp when starting on cold days.
If he’s coming out in 20° weather and his coolant temp is 90° then I’d say it’s working. But then again, maybe we can get some more numbers from people who use the engine block heater and see their numbers too.
If he’s coming out in 20° weather and his coolant temp is 90° then I’d say it’s working. But then again, maybe we can get some more numbers from people who use the engine block heater and see their numbers too.
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Mountain Pass
Joined: Dec 2024
Posts: 202
Likes: 110
I've had the block heaters on my previous 6.2 and the current 7.3 gassers, but I haven't used them much. However, I used the block heater on my 2004 5.9 Cummins extensively. For starters, a few seconds after plug-in, I could always heart a faint gurgle in the block as the antifreeze began to warm up. Almost sounds like a Keurig warming up. Similar principle. Second, while I never saw it melt snow or ice off the hood, it did a great job on the windshield. Many mornings I walked out to see a nice half-moon of clear windshield extending from the cowl.
Again, not saying this behavior extends to your 6.7, nor am I trying to compare apples and oranges, but a block heater is a block heater is a block heater too. It's simply heating antifreeze within the block.
Again, not saying this behavior extends to your 6.7, nor am I trying to compare apples and oranges, but a block heater is a block heater is a block heater too. It's simply heating antifreeze within the block.
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Laughing Gas
Joined: Apr 2023
Posts: 921
Likes: 1,867
From: SE PA
EDIT: If you really want to check the block heater has a resistance between 12.5 and 17 ohms.
Last edited by Strider250; Jan 26, 2025 at 06:17 PM. Reason: Added resistance values.
Trailering
Joined: Feb 2024
Posts: 20
Likes: 13
I'm pretty sure my coolant always says 86 when starting like it's the lowest it reports, but with the block heater I get around 89-93. I could be wrong, I'll check tomorrow morning as I am running trickle chargers with the cord so will not have it plugged in.
I have it on a metered plug and it runs 100% without stopping at approx 900w the whole 3 hours I have the plug active.
It does start instantly, no short delay on the glow plugs and the cab is warming up within half a mile. Supplemental helps there though.
I have it on a metered plug and it runs 100% without stopping at approx 900w the whole 3 hours I have the plug active.
It does start instantly, no short delay on the glow plugs and the cab is warming up within half a mile. Supplemental helps there though.
Hmm wonder what’s up with that.
Cargo Master
Joined: Jan 2017
Posts: 2,251
Likes: 563
easiest quickest way is just test with multimeter. sounds like the dash dispay is useless as it doesnt read below 80 ? if it read water temp with no limitations then of course this would also tell if the block heater was working
Cargo Master
Joined: Apr 2018
Posts: 2,410
Likes: 1,123
I haven't used any of mine in years, but I do remember at night seeing a spark and hearing it when plugging the extension cord in to the truck, assume the cord is plugged into a power source of course.
I don't think much has changed considering it's the same type of coolant heater that have been used for decades.
I don't think much has changed considering it's the same type of coolant heater that have been used for decades.
Logistics Pro
Joined: Jan 2010
Posts: 4,117
Likes: 1,645
Interesting to note that Ford changed the readout on coolant temp to not read below 86°. My Ram reads at least as low as 40...I haven't been in it and started it after sitting overnight, since it has remote start. It's a programming change, I would presume you could edit that with Forscan.
To the OP, at mid-20's, if it isn't waiting to start with the block heater plugged in, then the block heater is definitely working. My FIL's '24 waits to start at basically anything under about 35°
To the OP, at mid-20's, if it isn't waiting to start with the block heater plugged in, then the block heater is definitely working. My FIL's '24 waits to start at basically anything under about 35°
Banned
Joined: Jan 2025
Posts: 73
Likes: 21
From: Pennsylvania
The engine block heater is a wonderful feature, especially during cold snaps like the one you experienced in New Orleans. To determine if the engine block heater is working, look for these indicators:
1. Warm engine: As you've already observed, a working block heater will warm up the engine, making it easier to start in cold temperatures. A temperature reading of 80-ish on the water temp gauge is a good sign.
1. Warm engine: As you've already observed, a working block heater will warm up the engine, making it easier to start in cold temperatures. A temperature reading of 80-ish on the water temp gauge is a good sign.
Banned
Joined: Jan 2025
Posts: 73
Likes: 21
From: Pennsylvania
2. Cord warmth: When the block heater is functioning, the cord and plug might feel warm to the touch after a few hours of being plugged in.
3. Reduced cranking time: A block heater will help reduce the cranking time required to start the engine. If the engine starts quickly and easily, even in cold temperatures, it's likely the block heater is doing its job.
4. Coolant temperature: Use a thermometer or a scan tool to check the coolant temperature. If the block heater is working, the coolant temperature should be warmer than the ambient temperature after a few hours of being plugged in.
3. Reduced cranking time: A block heater will help reduce the cranking time required to start the engine. If the engine starts quickly and easily, even in cold temperatures, it's likely the block heater is doing its job.
4. Coolant temperature: Use a thermometer or a scan tool to check the coolant temperature. If the block heater is working, the coolant temperature should be warmer than the ambient temperature after a few hours of being plugged in.