What Temp Should I Use Block Heater? | The Diesel Stop

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Incorrigible I Thanks for all the great reads here here folks, I'm new to diesel. Here's the question: at what temperature should I be concerned about plugging the block heater in? Follow up question: Besides cold weather starting, do you consistently plug in more with an eye to prolong engine life? Follow up question x2: can engine or heater be damaged if remote started with block heater plugged in? Thanks in advance! #1 · Dec 29, 2012 Thanks for all the great reads here here folks, I'm new to diesel. Here's the question: at what temperature should I be concerned about plugging the block heater in? Follow up question: Besides cold weather starting, do you consistently plug in more with an eye to prolong engine life? Follow up question x2: can engine or heater be damaged if remote started with block heater plugged in? Thanks in advance! Sort by Oldest first Oldest first Newest first Most reactions #2 · Dec 29, 2012 I start plugging mine in at -10C but I also have an oil pan heater on my truck. IMO anything that makes it easier to start an engine will prolong its life. (I also have an oil pre-lube system) Engine running with block heater still on is a big no-no but I can't remember why though. Sent from my iPhone using AutoGuide.com App #3 · Dec 29, 2012 (Edited) I can't think of 1 reason why the block heater would be a problem while the engine is running ( other than you might drive off with it plugged in HaHa) matter of fact the last two times this came up everyone concurred that it was fine . I plug My truck in anytime I am leaving early and it's below 50 you heard Me LOL even in AZ I like a nice warm engine and I live a mile from the on-ramp so makes Me feel better about 3-4000 rpm I also have a oil pan heater ,, it's all on a timer for 3hours before I leave #4 · Dec 29, 2012 Living in N. Texas...hardly at all....we spend a lot of time in CO in the winter. I plug in when it gets to single digits. It seems to like that a lot better! Not sure why remote start and an active block heater would be an issue. I have owned a ton of these and there has never been anything in the owner's manual stating not to remote start with the block heater plugged in...its a pretty simple heater with no tie in to the trucks electrical at all....just don't drive off plugged in... #5 · Dec 29, 2012 From what I've read here, the 6.7L starts well down to around Zero degrees and with synthetic oil even below zero. But with that said, I'd recommend plugging it in any time the temp is freezing or below to save the strain on the batteries & starter. Plus the engine warms up much quicker and you'll have heat & defrosters almost immediately. The quick start up of the warmed engine reduces start-up smoke, promotes a better fuel burn that reduces fuel dilution of the engine oil, and lets the oil circulate faster to critical engine parts like pistons, main & rod bearings, the turbo bearings, etc. I use a heavy-duty timer set to warm the block heater up about three hours before I normally start the engine in the morning. That's enough time to thoroughly warm the engine and not run up the light bill excessively. Many of us have used the block heater on running engines, and starting the engine with the block heater plugged in is common so using your remote start should be O-K. However extended idling to warm your truck engine should be kept to a minimal amount. An idling engine takes much longer to get to operating temp than an engine that's put under some load driving at low loads & speeds. Plus running a diesel engine in a closed garage is not very safe to begin with. There was a discussion here a year ago about use of the block heater on the 6.7L setting a trouble code on the engine due to some tempurature being outside the acceptable parameters of the engine management computer. I seem to remember only 3 trucks having this issue but FMC was working on the situation about the time temps warmed up last spring and the discussion died. Cold starts are a terrible thing to do to ANY engine. I've had block heaters on most of my gas engines as well as any diesel that may have to run year-round. #6 · Dec 29, 2012 (Edited) Driving away with an extension cord still connected could be a problem, but that's about it. The coolant's circulating, preventing any hotspot from forming, and the radiator & heater core can easily dissipate an extra thousand watts. #7 · Dec 29, 2012 (Edited) Agreed the block heater will never get a system up to operating temps so once the engine is running I cant see it pushing the motor over normal operating temps in the say 15 minutes you may have it running on remote start I Know my 6.0 won't I also suggest the Marinco mod to help with the drive off with the cord in issue LOL http://www.thedieselstop.com/contents/getitems.php3?Marinco Block Heater Plug Mod #8 · Dec 30, 2012 Forget about when to use it. I'm more interested in what the temp spread is when it's used. The other week I was using it and never got more than a 15 degree spread. The funny thing is the tranny always showed 19 (OAT was between high 20's & low 30's) but came up immediately to ambient when running. There was a pretty good wind chill but not that much... #9 · Dec 30, 2012 Any temp below 40 and my truck gets plugged in. #10 · Dec 30, 2012 (Edited) Basic rule of thumb, if its going to freeze, 32*, plug it in. It just makes life more pleasant in the morning! Being a calif truck, mine didn't come with one and didn't order it that way. Kinda miss it as my 7.3 had one and made cold mornings great! #11 · Dec 30, 2012 It's really a comfort issue for the driver. If the truck has been plugged in, Your coolant will be warmer, and hence it will reach the temp where it will start blowing hot air out of the ducts faster. Previous diesels trucks I've owned, had always came with the element and you just needed to add the cord. So I didn't order the block heater on this truck assuming the same. And now I have no block heater. I spent most of last winter in a much colder place. Truck was parked outside in -25°F temps and I usually hit the remote start. I did use synthetic oil and the truck always just purred to life when I hit the remote. If you look at Fords opinion. They consider the block heater unneccessary is 35 states. Since it's only available as an option in those areas. #12 · Dec 31, 2012 Agree with Painted Horse, although I usually start plugging in a little earlier, around 0 to +5F, but I don't have any data to back up *why* I do that other than I've always done it that way. I never plug in for more than 2 hours (usually ~1 hr) prior to starting, and Jan-Feb can regular see -20 or -30F with stiff winds blowing in my usual travel around MN or over to SD and WY. Regarding the engine running with heater plugged in: I had always started my 6.0 and currently remote start my 6.7 with the engine block heater plugged-in and never have had any problems. As expected, my coolant temp normalizes (>190F) much sooner once i start driving if its been plugged in, with seemingly no effect on tranny coolant temp. 1 Reply #14 · Dec 31, 2012 Just hasn't been an issue. The truck starts when I push the remote button. I do use the Synthetic oil in the colder months to make it easier to get oil flowing. If I was having trouble getting it started on cold morning, I'd get the block heater added. But right now I push the button, 5 seconds later, the engine cranks over and it usually fires up on the 2nd or 3rd revolution. This winter, I'm back in Utah and normal night time temps are 15-20° for two months. Remember Roeckler, You have two seperate cooling systems. A engine block heater, heats the coolant in the engine. But the tranny, CAC, Fuel and EGR are all cooled by the secondary coolant system. So your block heater has no effect on those components. And you should not expect to see a warmed up tranny from being plugged in. #15 · Jan 2, 2013 If I recall Ford recommends pluging the 6.7L in a -23C. I plug in at -15C and the truck has started great every time. Takes about 3 or 4 mins for heat to start comming out the vents and the seats to start to warm. I use my remote start to start my truck every time my truck is plugged and leave it like that until I am ready to leave and never ran into any problems at all. Good Luck #16 · Feb 23, 2016 LOL! I did it twice this year. #17 · Feb 23, 2016 (Edited) The various block heater manufacturers provide the following instructions: DO NOT RUN YOUR ENGINE WHILE THE ENGINE HEATER IS PLUGGED IN. This will create an air bubble around the element which will them cause the element to burn out prematurely. Edit: OK, sorry, I just saw that the previous poster brought this thread back from the dead. Insert Quotes Post Reply

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