6.9 serial number

Discussion in '6.9L IH & 7.3L IDI Diesels' started by KGIA103, Jan 13, 2018 at 6:47 PM.

  1. KGIA103

    KGIA103 Registered User

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    Just needing some confirmation on which updates my 6.9 has and if this is possibly the original engine in my 86 250.
    Looks like serial number is... 6.9DU2U247433.

    Also included is a picture of the block heater and freeze plug area found on passenger side just above the starter. The heater looks new but I'm hesitant to use it as I'm not sure my block won't crack.
    Thanks.
    IMG_20180113_142651.jpg
    IMG_20180113_152232.jpg
     
  2. KGIA103

    KGIA103 Registered User

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    Also, is there usually an asterick (*) of sorts at the end of the serial number?

    It's hard to tell in the picture, but there appears to be an asterick or a 1 after 47433. But 474331 doesn't make sense for a number on a 6.9 from what I understand...
     
  3. DaveBen

    DaveBen Supporting Member Supporting Member

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    The block heater will not hurt the block! it just warms up the water before you hit the starter. Truck jumps to life quicker.
     
  4. KGIA103

    KGIA103 Registered User

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    I've been reading about which serial numbers have the reinforced block heater plug, all 6.9s not built the same... Are you aware of that issue? That'swhat I'm asking about.
     
  5. IDIBRONCO

    IDIBRONCO IDIBRONCO

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    The later 6.9 blocks weren't reinforced, they were cast thicker in this location. From looking at your picture, it appears that you have the thicker block although it's hard to tell. The block appears to "wrap" around your dipstick tube like it does on the 7.3 blocks. Maybe I was told wrong, but what I heard was that if you plugged in the earlier engines with the engine at operating temperature, then you greatly reduce the chances of it cracking.
     
  6. TahoeTom

    TahoeTom Supporting Member Supporting Member

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    Here are the changes by serial# for 6.9's Looks like you have a high # so you have all the updates. You may have the 7.3 style rocker arms also, though they were introduced in '87. The earliest 6.9's had a problem with the block cracking if the block heater was used, but you should be good to go. I think the asterisk was used to prevent someone adding an additional number.

    Image (4).jpg
     
  7. snicklas

    snicklas 6.0 and Loving It!! Staff Member

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    Looks like 173,828 was the improved block. Yours being 247,433, or the important part, 24*,*** you should have the thicker block. Yours is higher than the last number on that list.
     
  8. KGIA103

    KGIA103 Registered User

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    Somewhere I got mixed up and thought the second "u2" was the made in USA code... And thought my serial number was only 47433.
    Glad to realize my error.

    So this is one of the last 6.9s? And probably original engine in a truck made 09/85?
     
  9. icanfixall

    icanfixall Official GMM hand model

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    The block number you posted is the upgraded block.Its the desireable block most want. The first 7.3 block serial number started at 500,079 and went up to 1,116,330. Then the turbo block came about 1,116,331 and up from there.
     
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  10. OldIron82

    OldIron82 Full Access Member

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    Awesome block#! I've looked for two years to find one that high with all the updates. Unfortunately I settled for a running 85 with the thicker block but still pressed on cooling jets. I simply swapped in 7.3 rockers.

    Sent from my LG-H810 using Tapatalk
     
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  11. snicklas

    snicklas 6.0 and Loving It!! Staff Member

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    Yep, the id number is:

    6.9DU2U247433

    Lets break that down for everyone.

    6.9D - This indicates a 6.9 Liter Diesel (naturally aspirated). In the 7.3 there was 7.3D and 7.3T, D was N/A, T was a Turbo Block.

    U2U - United States Production and which plant. Most for the Navistar Diesels installed in Ford Chassis were produced at the Navistar Plant on Brookville Road in Indianapolis, Indiana. This plant made the 6.9/7.3IDI, 7.3/6.0/6.4PSD Engines.

    https://www.google.com/maps/@39.7586345,-86.0702749,603m/data=!3m1!1e3

    247433* - This is the +1 serial number for this block.

    This is actually a carryover from IH back in the day. They did this with most of what they produced. I recognize the format from my IH Built Cub Cadets.

    This is the Kind Code/Model Code/Production Location/Serial Number type format.

    For Example:

    My IH Cub Cadet has a Serial Number of:

    2050660U620571 - The breakdown for these serial numbers are: 205 0660 U 620571

    Notice the similarity in the format? We can break this down, and it will help the IDI number make sense.

    205 - This is the Kind Code, it indicates an IH produced Cub Cadet Garden Tractor. There are other kind codes for the Rear Engine Riders, and the IH Cadet Lawn Tractors.

    These are Garden Tractors (actually mine) and the one on the left without a mower deck is the 1450 I'm referencing.

    Kind Code 205:
    [​IMG]

    This is a Rear Engine Rider:

    Kind Code 034:
    [​IMG]

    This is a IH Cadet Lawn Tractor:

    Kind Code 035:
    [​IMG]

    0660 - This is the Machine Code, which indicates a 1450 Model.

    U - This indicates this product was Made in the United States. In the case of IH Cub Cadet Garden Tractors, they were ALL produced at the Louisville Plant. This plant has been demolished and the location is under the runway of the Louisville Airport.

    620571 - This is the +1 serial number. It was the 620,070'th unit off the line. Like a lot of IH products the first production serial number was 501. There are some 400 serial numbers that exist. but they are "pre-production" models for testing and development. There is also a listing we have that has the beginning serial number for each month, so we can figure out the month the tractor was produced. (I wonder if there is something floating around for the engines). So, mine was produced December 1977. The first number is 620,313 and the first one for January 1978 is 621,744. So 1,430 were produced in December, 317 per week, 63 per day. So mine being 620,571, that is the 258th unit produced that month. Doing the math, (4.1 days) mine should have been made during the 4th day of production. Looking at the calendar that should have been before lunch on Tuesday, December 6, 1977.

    So if you compare the numbers:

    6.9DU2U247433

    2050660U620571

    You can see the "method to their madness" with their numbers. Their serial number has more information embedded than just a serial number.

    They use a similar system for their part numbers. At one point in time, the part numbers looked like this:

    IH-549930-R1 - This was an IH Part Designation-Part Number-Revision Number. There are times when you are looking for a part, it will come back with a, now use IH-549930-R2, which means they updated the original part, and now this is a revised part.

    Now the part numbers look like this:

    1807974C94 - This is how the part numbers now look. When the IH name was sold, it was dropped IH, but it still has the Part Number and a Revision Number. So this one is 1807974 for the part number and C94 is the current revision.

    **A bonus here- the 1807974C94 Part number is the current IH/Navistar/International part number for a 6.9/7.3 IDI Thermostat and Gasket**. I think I will add this to the parts bin also.....
     
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  12. IDIBRONCO

    IDIBRONCO IDIBRONCO

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    Let's not forget the serial numbers that had DM2U instead of DU2U. I don't know which plant they were made in, but this meant that it was originally in an International instead of a Ford.
     
  13. KGIA103

    KGIA103 Registered User

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    DU2U means international truck? All Ford 6.9 were DM2U? How can I find more info? Hmm, this is getting interesting.

    Here is some good info from an international document:

    Engine Identification
    On New OEM engines, the 6.9L and 7.3L can be identified by the permanent engine number stamped on the front
    top left side of the engine. This engine number tells much about the engine. An example of this engine number is
    the engine number 69LDM2U345678. The first three positions indicate the engine displacement, in this case
    6.9L. The fourth digit D, indicates a naturally aspirated or non-turbocharged engine. The fifth and sixth digits M2,
    indicate an engine built for truck use. The seventh digit U, indicates that the engine was built in the U.S.A. The
    rest of the digits 345678, represent the specific engine serial number. Early 6.9L engines with serial numbers
    below 59208 are known as 6.9A series and ones with serial number 59209 and higher are known as B engines.
    The 7.3L engine serial numbers begin with 500001. On ReNEWed™ engines, the serial numbers are in the same
    location as New OEM engines, but the fourth digit is a F, which indicates a naturally aspirate or non-turbocharged
    engine.
    Note: ReNEWed engines use the latest designed components. SN breaks do not apply.

    It confirms the M2 used for truck use, but doesn't say about U2...any ideas?
     
  14. IDIBRONCO

    IDIBRONCO IDIBRONCO

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    DM2U was for Internationals. DU2U was for Fords.
     
  15. KGIA103

    KGIA103 Registered User

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    I see, that sets me straight.
     

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