Factory Block Heater Cracking Early Blocks: What Years??!!!???

[cleithau]

I just read how the factory block heaters in early 6.9 engines could crack the block. What is early, mines a 1985? I put a new factory 1000W block heater in last year before I knew about any problems. Should I not use it or am I OK to plug it in? I have only used it a few times.

 

[Diesel JD]

There were a set of serial #s that were the old casting, and after they updated it, people usually were OK. Maybe you can find it with the search feature or maybe somebody knows off the top of their heads. An 85 could be updated or early casting I think late 84 early 85 was when they fixed it.

 

[Jake S.]

ser # 59209 built in late 1984 and anything newer are the "b" model motors. I believe that is when the blocks got better. Check ser. # by the ip drivers head. Otherwise on the side of the block look between the frost plug holes. If the block is the same height as the plugs than it is a new style.

 

[cleithau]

Do you mean the block is recessed around the freeze plugs and earlier models and it is all the same thickness in later models?

 

[Joe Mc]

According to the information I have, the updated casting was implemented starting with block number 173828 (which translates to roughly halfway through the '85 model year). This was a different change than the "A" to "B" models.

 

[The Warden]

According to the information I have, the updated casting was implemented starting with block number 173828 (which translates to roughly halfway through the '85 model year). This was a different change than the "A" to "B" models.

+1

The change from the "A" to the "B" model occurred in early to mid '84, actually. The only "A" blocks you'll see are '83 and early '84. However, as Joe said, the block casting improvement occurred in mid '85.

 

[Jake S.]

Do you mean the block is recessed around the freeze plugs and earlier models and it is all the same thickness in later models?

Exactly. But Between each frost plug is lower on the early ones. The plugs themselves are the same height.

 

[mankypro]

Has anyone actually ever owned a block that cracked and positively identified the source as the block heater? No second hand stories.

 

[nightrunner84]

Yea, I'd like to know too. I have an 87 6.9 but looking at the freezeplugs, the block is recessed around the "hump" the plug is in. Am I ok to use the heater? I just want it to keep the truck warm while I'm at work.

 

[cleithau]

I just checked mine and its and 85 and the block is flush with the heater. I would have been bummed if I had put a heater in I couldn't use.

 

[Agnem]

All I can say is I used my block heater for the first few years I owned the Moose Truck. Didn't learn it was risky until it (should have been) way too late. I'm glad mine wasn't one of the unlucky ones. I don't think your going to read about any anymore, under my theory that the ones that are going to crack already have, and the ones that aren't, won't. I supose the potential always exists that somebody down south could sell one to a new owner where it is cold enough to use it, but that seems only likely to happen to somebody who found said truck through a knowledgeable forum which would have already edumacated said individual not to use it.