6.9 block heater?

adam g

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Where is a safe place to put a block heater on a 6.9? I heard that freeze plug style htrs can crack the block. Any recommendations?
 

Knuckledragger

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The stock ones are in the freeze plug hole, can't do much better than that. And no, they don't crack the block. That is what happens if you do not use coolant or a heater and let the truck freeze overnight.
 

jhnlennon

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83-early 85 engines had issues with the block cracking around the block heater. Well documented. Alot of people run a circulating tank type heater, there might be a lower radiator hose heater available to.
 

Diesel JD

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jhnlenon has the correct answer. Somewhere on here there probably is the info on the serial # breaking point where IH fixed this casting defect. It's probably safe to say if the engine was built in late 1985 or later you can just use the stocker. Mine is an 86 and has a Dec 85 build date. I use the block heater with no issues
 

dyoung14

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Yes if its a 83 84 and some 85 blocks un plug the block heater and throw the plug away cause it can cause your block to crack, the later blocks didnt have the prblem
 

dyoung14

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jhnlenon has the correct answer. Somewhere on here there probably is the info on the serial # breaking point where IH fixed this casting defect. It's probably safe to say if the engine was built in late 1985 or later you can just use the stocker. Mine is an 86 and has a Dec 85 build date. I use the block heater with no issues

posted at the same timeLOL
 

adam g

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It was in an early 84 truck and I plan on using a lower hose heater. Thanks guys.
 

ulmapache

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So, how long can I use the stock block heater? I've got an 84. Can I plug it in for a couple hours in the am, or just not use it at all...
 

Kevin 007

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If it is an 84, just stop using the block heater. You can leave it in place, but upgrade to a lower coolant hose heater (easiest upgrade) or circulating type heater and not risk the block cracking. They don't ALL crack there, but they can, in those early years.

With the lower rad hose heater (I have many in use) use good clamps and re-torque the clamps after a few heat cycles and then check them again annually, as the rubber rad hose material compresses and settles slightly with all the heat cycles. That's the only real problem with the lower rad hose style heater, and its hardly a problem IF you check up on your clamps and use good ones. They are not as effective as a block heater but they work fine. And install it closer to the engine opposed to closer to the rad, when you decide on a spot in your lower rad hose to install it. If its closer to the rad, then most of the heat will go to the rad instead of towards the engine, and in the engine is where you want it.
 
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Kevin 007

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I wouldn't even try. Nor would I try magnetic pan heaters. I mean, "I" have tried them both in the past, but wouldn't recommend it. Neither are efficient. A lower rad hose heater or circulating heater hose heater are going to be you next best bet. A wabesto is another option, but that's in a whole different league
 

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