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Experts, I need your help:

I know that "IF" and "CI" are the radiator side tank codes.

I also know that "EC" is the radiator assembly code, found in both GM assembly manual and also the build sheet code.

But, what does the "74" mean???

 

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Experts, I need your help:

I know that "IF" and "CI" are the radiator side tank codes.

I also know that "EC" is the radiator assembly code, found in both GM assembly manual and also the build sheet code.

But, what does the "74" mean???

I'd like to know myself.

Lance, the "74" can't be a production year designation as was speculated on the Oldsmobile web site because the code for my '70 Elky radiator is 53. Gotta be something else.

Rich
 

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it is a date code .. may be a julien date code month, of the year the car was built ... as part of the brodcast code .

there numbers make no sence as a actual date .. but if you have worked in the big three factory you know julien dates are strange as related to a normal date of the year .
 

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FWIW,

The 1968-1969 version of the radiator tag was larger than the 1967 tag and added the codes for the radiator end tanks in a smaller font next to the broadcast code. On this larger tag, beneath the broadcast code and tank codes, is a row with a 1 or 2 digit number and the letters O, R, or S. The meaning of this row of characters is unknown, as is the meaning of the extra number stamped after the part number.
http://www.camaros.org/coolingsystems.shtml
 

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it is a date code .. may be a julien date code month, of the year the car was built ... as part of the brodcast code .

there numbers make no sence as a actual date .. but if you have worked in the big three factory you know julien dates are strange as related to a normal date of the year .
I suspect that you might be right about the number being a date code of some kind but I'm not so sure about it being a Julian date. If I understand the Julian calendar, the same number (00 through 99) for any given month will appear four times within a 12 month period, based on the day of the month. For example, the "4" on Kieth Tedford's tag could be January 4th, April 14th, July 23rd or October 31st. Without the day code (1 through 31) that determines the month code on any given day, it would seem that having the possibility of a manufacturing date by month being one of four possibilities wouldn't make much sense.

Sounds like the only way we'll ever know is to hear from someone who worked with these numbers back in the day.
 

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I suspect that you might be right about the number being a date code of some kind but I'm not so sure about it being a Julian date. If I understand the Julian calendar, the same number (00 through 99) for any given month will appear four times within a 12 month period, based on the day of the month. For example, the "4" on Kieth Tedford's tag could be January 4th, April 14th, July 23rd or October 31st. Without the day code (1 through 31) that determines the month code on any given day, it would seem that having the possibility of a manufacturing date by month being one of four possibilities wouldn't make much sense.

Sounds like the only way we'll ever know is to hear from someone who worked with these numbers back in the day.
I was thinking that as in the number 74 it might have been 7th month 4th day .
I do know its a date code but how to determine the date is a mistery .. the build manuals dont have it from what i have heard .

Don
 

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I was thinking that as in the number 74 it might have been 7th month 4th day .
I do know its a date code but how to determine the date is a mistery .. the build manuals dont have it from what i have heard .

Don
Yes Don, I hear ya, but that theory doesn't work either when it comes to a single digit like Keith's #4. Is that the 4th day or the 4th month? All that I've ever seen is one and two digit numbers so if a build date happened after the 9th day of any given month, there would have to be three numbers such as 714 indicating the 7th month and the 14th day.

It would be easy to assume that it's just some screwy numbering system that the manufacturer (Harrison) of the radiators dreamed up, but that same screwy numbering system finds its' way into the automobile manufacturers' (Chevrolet) system by way of the number appearing on the broadcast sheet. Even the proliferation of the large, two letter codes on the tags is enough to make your head spin. Anyway, it's fun speculating as to what they all mean. Keep trying!
 

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On ark 68 RADIATOR tag

I JUST WENT THRU THIS LAST YR WITH MY 69,I DID A LOT OF RESEARCH AND THERE ISNT MUCH INFO OUT THERE ON RADIATORS EITHER AND I HAVE A LOT OFLITTERATUR GM AND OTHER RESTO BOOKS ETC AND STILL NOT MUCH GOOD INFO ON RADIATOR DECODING.

I GOT MOST OF MY INFO HERE FROM TEAM CHEVELLE MEMBERS IN THE KNOW THAT DO PROFESSIONAL JUDGING ETC.

SO FROM WHAT I LEANERD THE "J" INBETWEEN X & F ON TANK MEANS 10TH MONTH/OCT BUILD.

THE XF & IA ARE THE DESIGNATION IDS FOR LEFT AND RIGHT RADIATOR TANKS DEPENDING ON HOW MANY CORE THE RADIATOR IS.

THE OP IS DESIGNATOR FOR IF ITS A 2 CORE/3 CORE/OR 4 CORE RADIATOR FOR OPT HD COOLING OR FOR AC FOR A 68 CHEVELLE SS 396 .

AS FOR THE 25 ON THE BOTTOM OF THE TAG,THAT I AM NOT TOO SURE OF AT ALL AND I COULD NOT GET AN NAS FOR IT EITHER. BUT IT MAY MEAN THE RADIATOR IT SELF OR RAD TAG WAS BUILT/STAMPED ON 25TH DAY OF 10TH MONTH/OCT THAT THE RAD WAS BUILT BUT I AM NOT SURE ABOUT THAT ONE.

Again,thats the way i understand it to be but if anyone has a diff take on it by all means post it so we can all collectively try to figure it out what the correct scoop is on it for all to learn from.

SCOTT
 

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On ark 68 RADIATOR tag

AS FOR THE 25 ON THE BOTTOM OF THE TAG,THAT I AM NOT TOO SURE OF AT ALL AND I COULD NOT GET AN NAS FOR IT EITHER. BUT IT MAY MEAN THE RADIATOR IT SELF OR RAD TAG WAS BUILT/STAMPED ON 25TH DAY OF 10TH MONTH/OCT THAT THE RAD WAS BUILT BUT I AM NOT SURE ABOUT THAT ONE.

Again,thats the way i understand it to be but if anyone has a diff take on it by all means post it so we can all collectively try to figure it out what the correct scoop is on it for all to learn from.

Scott,

My number is 53 and the number in Lance's example is 74 so day of the month doesn't work. Also, just curious - in your example above how would you determine that production was the 10th month?

Rich
 

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HI Rich,well just like i already stated in my 1st post for the ARK/68 example ,look at the " J " inbetween the X & F on the tanks of his radiator in his photo.

The J = 10th month/October & in my car's case it was the letter C inbetween letters on the rad tank & C = 3rd month /March.

But as i also already stated i was nor sure at all about the 25 on Arks rad tag so i cant ans that same question of thats the &$ /25/etc mean for any of the examples here in this post.

So maybe someone else will chime in to insert that piece of the puzzle so we will be that much closer to having decoding radiators nailed down.

But is seems you need both that rad tag and the rad itself to fully decode a rads beginings.you cant do it from the rad tag or radiator itself alone without having both on hand to complete all the required info other then what the build sheet states was the radiator your car was ordered with/came with .

That's what i learned form researching it myself & thats the best i can tell you on that one.

Scott
 

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Some interesting info on the Camaro research group .. to bad theres not one for Chevelles .

http://www.camaros.org/coolingsystems.shtml#tag
click on the tab for radiator tags .

still ...On this larger tag, beneath the broadcast code and tank codes, is a row with a 1 or 2 digit number and the letters O, R, or S. The meaning of this row of characters is unknown, as is the meaning of the extra number stamped after the part number

Julian Calendar Generator
GM dated some components using a Julian type of calendar, where the days are counted continuously, starting on January 1st. For example, February 1st would be day 32. The calculator below will generate the Julian calendar for the 1966 through 1969 calendar years.

see this link
http://www.camaros.org/numbers.shtml#Calendar

try out the Julian Calendar Generator
it may be the reason there could be 3 numbers at the bottom of some tags such as 32 to the left and a 0 to right .

as to when the radiator was produced for tracking reasons .

As Scott stated there is a month code stamped into the tank .. but the tag date code /Julian date may be a day of the year the rad was produced .

Im about ready to Call Delphi/Harrison and beat up some people to get to the bottom of this ... LOL
 

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HI Rich,well just like i already stated in my 1st post for the ARK/68 example ,look at the " J " inbetween the X & F on the tanks of his radiator in his photo.

The J = 10th month/October & in my car's case it was the letter C inbetween letters on the rad tank & C = 3rd month /March.

Scott
Scott, I had a brain freeze. Completely forgot about the month code stamped in the tank. Thanks for the reminder.

Rich
 

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Rich/NP,happens to me at times too and my fumble fingered typing/typo's are horrible at times which i am sure is something i am known for here in team chevelle,/LOL!!!!!!!!!!

Scott
 

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Discussion Starter #19
Has anybody ever noted a change in the two digit radiator tag codes talked about in this thread in two cars of the same year and options, but different build dates???

If not, maybe a code for which assembly line at the Harrison factory the radiator may have been assembled on???

Or..... maybe a code issued to each quality control inspecter at the plant, responsible for the final inspection???
 
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