6.9idi Block Heater

[Hayden simpson]

I have an 85 F250 and am living in Colorado. With the cold winters I am hesitant to use my block heater until I am sure that my block is not one of the ones prone to cracking. First does anyone know how I can check my serial number to see if it is safe and does anyone have experience with lower radiator hose heaters(im thinking of installing one until I know what block I have). Thanks For the Help.

 

[IDIBRONCO]

If your engine is original to your truck, I would think that by 1985, it should be safe to use the block heater. Somebody on here will probably be able to give you the serial number breakdowns. From what I've seen, I don't think that the radiator hose heaters are as effective as the factory style ones are.

 

[Scotty4]

Copied from a past post:

6.9 blocks up to serial #u2u17900 had a thinner casting around the block heater. It is very common for these blocks to crack.


6.9L Old Style Block

Block Casting Number:


On left side of block (beneath oil cooler) 1805440C1
Note: Some 440 blocks are truly new style and must be visually inspected by raised donut around the block heater, frost plug (right rear). Old style below serial number 173828.
Visual Identification: *No counter bored area for block heater
*No defined area on side of block for dip stick
*Thickness of cast iron around block heater 3/8" (.375")
Head Bolts: *7/16, 12 point socket is used to torque head bolts
*Block tapped with 7/16-14 for head bolts

6.9L New Style Block

Block Casting Number: 1807996C1 Note: Some new style blocks have casting
number 440. Above serial number 173828.
Visual Identification: *Has counterbored area for block heater
*Very defined relief area cast in side of block for dip stick tube.
*Thickness of cast iron around block heater 15/32" (.470")
*Latest style (not all new style 6.9) has ribs around head bolts, rear two on left side go from head gasket surface to pan rail - same as 7.3
Head Bolts: *Same as old style 6.9