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[Part 2] ****UPDATED 9/20/09****
IV. Date codes; Meaning of Tank codes; Tags:
With very few (if any) exceptions, all original 66-67 Harrison radiator tanks should have a 2-letter identification code on them. The top tanks will also have a smaller third letter in between the two larger letters, which is a date code. There is also a date code stamped on the mounting channel on the driver's side.
Date Codes - The date code on the top tank is the month when the tank was stamped out. It is the usual letter-per-month format, with the letter 'I' omitted (so M=December).
The date code on the mounting channel on the driver's side is the date the channels were stamped out and/or the date the strap assembly was made. That date should be the same as the upper tank date, or one month before, or one month after.
So, if a car has its original radiator, the tank date code or the strap date code (whichever one is later) should match or precede the car's body build date on the cowl tag (bearing in mind that a car with a 05D cowl tag date, for example, could easily have a E dated radiator that was assembled earlier that same month).
Tank Codes - If you think about how the Harrison radiator assembly line would have worked, each radiator was an assembly of several parts - a top tank, a bottom tank, a core, and a set of straps and mounting channels (and in some cases a finger guard). The large 2-letter stamping is just the identification code for the tank itself. They are the rough equivalent of a build-sheet code for the tank piece for the Harrison radiator assembly line worker. Since the same tank could be used on multiple different radiator applications, the same tank codes can be seen on different radiators as long as the tank is the same (even though the radiator p/n’s and the Chevrolet B/S codes for each radiator are different).
With that said, I have seen three Middle sized 3-row radiators that did not have a visible top tank code (but did have the date stamp). The normal code for that top tank is UP (see below). All three of those unstamped tanks have been dated J or K (Sept. or October, of either 65 or 66, unless they are service replacement radiators). I don’t know if this was just an odd batch of top tanks that did not get stamped, or if all three of those radiators were later service replacement units.
B/S Tags - Harrison attached this small metal tag to the lip of the top tank, showing the Chevrolet p/n and Chevrolet B/S code. Once the radiator was completed and shipped, to Chevrolet, the tank codes were irrelevant to the Chevrolet assembly line worker, and only the p/n and B/S code on the metal tag mattered. Example:
Photo by Jeff Helms:
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Core ID tags (maybe ??) - In rare cases (on original radiators that have never been to the repair shop) you also see an additional very small metal tag attached to the top lip of the core (where it mates to the top tank) with another 2-letter code on it. Example:
Photo (and blur) by Jeff Helms:
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I have seen speculation that this tag shows the assembly date of the entire radiator unit. However, I can find no way to make any workable date combination out of the letters seen on different tags. In addition, I have seen the same “BG” tag on multiple Middle sized 66 radiators with widely varying tank dates; which makes it less possible that the small tag was an assembly date code (there is no way that three radiators with tanks stamped many months apart would all have the same radiator assembly date).
All those 66 radiators with BG tags (all of which have exactly the same core) have led me to believe now that this small tag is the Harrison identification code for the Core itself (used by the Harrison assembly line worker the same way as the tank codes discussed above). But that is just educated speculation. Unless many more radiators with that small tag are found, we’ll never know for sure. I have listed this code below under the applications where I have seen the BG tag present.
V. Specific applications, p/n’s, B/S codes, and tank codes:
- 1966 L35 or L34 with Manual Trans:
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Courtesy Mike Crown:
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- 1966 L35 or L34 with PG:
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Courtesy Mike Crown:
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- 1966 L35 with manual trans and A/C, AIR, and/or HD radiator;
and L34 with manual trans and AIR (without A/C or HD Radiator):
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Radiator in L34 manual with smog (Courtesy Mike Crown):
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- 1966 L35 with PG and A/C, AIR, and/or HD radiator;
and L34 with PG and AIR (without A/C or HD Radiator):
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Photo by Jeff Helms:
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[End Part 2, continued below]
IV. Date codes; Meaning of Tank codes; Tags:
With very few (if any) exceptions, all original 66-67 Harrison radiator tanks should have a 2-letter identification code on them. The top tanks will also have a smaller third letter in between the two larger letters, which is a date code. There is also a date code stamped on the mounting channel on the driver's side.
Date Codes - The date code on the top tank is the month when the tank was stamped out. It is the usual letter-per-month format, with the letter 'I' omitted (so M=December).
The date code on the mounting channel on the driver's side is the date the channels were stamped out and/or the date the strap assembly was made. That date should be the same as the upper tank date, or one month before, or one month after.
So, if a car has its original radiator, the tank date code or the strap date code (whichever one is later) should match or precede the car's body build date on the cowl tag (bearing in mind that a car with a 05D cowl tag date, for example, could easily have a E dated radiator that was assembled earlier that same month).
Tank Codes - If you think about how the Harrison radiator assembly line would have worked, each radiator was an assembly of several parts - a top tank, a bottom tank, a core, and a set of straps and mounting channels (and in some cases a finger guard). The large 2-letter stamping is just the identification code for the tank itself. They are the rough equivalent of a build-sheet code for the tank piece for the Harrison radiator assembly line worker. Since the same tank could be used on multiple different radiator applications, the same tank codes can be seen on different radiators as long as the tank is the same (even though the radiator p/n’s and the Chevrolet B/S codes for each radiator are different).
With that said, I have seen three Middle sized 3-row radiators that did not have a visible top tank code (but did have the date stamp). The normal code for that top tank is UP (see below). All three of those unstamped tanks have been dated J or K (Sept. or October, of either 65 or 66, unless they are service replacement radiators). I don’t know if this was just an odd batch of top tanks that did not get stamped, or if all three of those radiators were later service replacement units.
B/S Tags - Harrison attached this small metal tag to the lip of the top tank, showing the Chevrolet p/n and Chevrolet B/S code. Once the radiator was completed and shipped, to Chevrolet, the tank codes were irrelevant to the Chevrolet assembly line worker, and only the p/n and B/S code on the metal tag mattered. Example:
Photo by Jeff Helms:
Core ID tags (maybe ??) - In rare cases (on original radiators that have never been to the repair shop) you also see an additional very small metal tag attached to the top lip of the core (where it mates to the top tank) with another 2-letter code on it. Example:
Photo (and blur) by Jeff Helms:
I have seen speculation that this tag shows the assembly date of the entire radiator unit. However, I can find no way to make any workable date combination out of the letters seen on different tags. In addition, I have seen the same “BG” tag on multiple Middle sized 66 radiators with widely varying tank dates; which makes it less possible that the small tag was an assembly date code (there is no way that three radiators with tanks stamped many months apart would all have the same radiator assembly date).
All those 66 radiators with BG tags (all of which have exactly the same core) have led me to believe now that this small tag is the Harrison identification code for the Core itself (used by the Harrison assembly line worker the same way as the tank codes discussed above). But that is just educated speculation. Unless many more radiators with that small tag are found, we’ll never know for sure. I have listed this code below under the applications where I have seen the BG tag present.
V. Specific applications, p/n’s, B/S codes, and tank codes:
- 1966 L35 or L34 with Manual Trans:
P/N – 3007620 (this is a “Medium sized” 3-row radiator with finger guard)
B/S code – VX
Finger guard
Cap on Driver’s side
Top tank code – UP
Bottom tank code – CS or LY.
Sources for p/n and B/S code info –
- 66 AIM, Sec. 11-13, Pg A-8
- P&A dtd 7-1-66
- Original 620VX radiator with B/S and P/N tag, picture attached
- Multiple pics of VX tags on T.C.
Photo by Jeff Helms: B/S code – VX
Finger guard
Cap on Driver’s side
Top tank code – UP
Bottom tank code – CS or LY.
- CS seen on unit dated L (Nov. 1965 or 1966, year uncertain).
- LY seen on unit dated K (Oct. 1965 or 1966, year uncertain).
- LY seen on unit dated E (May 1966 or 1967, year uncertain).
- LY seen on unit dated G (July 1966 or 1967, year uncertain).
NOTE – we need some help on pinning down exactly when this tank code changed.
Core ID (?) tag – BG (seen on multiple original radiators with VX tags)- LY seen on unit dated K (Oct. 1965 or 1966, year uncertain).
- LY seen on unit dated E (May 1966 or 1967, year uncertain).
- LY seen on unit dated G (July 1966 or 1967, year uncertain).
NOTE – we need some help on pinning down exactly when this tank code changed.
Sources for p/n and B/S code info –
- 66 AIM, Sec. 11-13, Pg A-8
- P&A dtd 7-1-66
- Original 620VX radiator with B/S and P/N tag, picture attached
- Multiple pics of VX tags on T.C.
Courtesy Mike Crown:
- 1966 L35 or L34 with PG:
P/N – 3007621 (this is a “Medium sized” 3-row radiator with finger guard)
Identical to a 3007620 except it has trans cooler lines.
B/S code – VY
Finger guard
Cap on Driver’s side
Top tank code – UP
Bottom tank code – DC, BK or BG.
Source for p/n info –
- 66 AIM, Sec. M35, Pg A-27
- P&A dtd 7-1-66
Courtesy Mike Crown:Identical to a 3007620 except it has trans cooler lines.
B/S code – VY
Finger guard
Cap on Driver’s side
Top tank code – UP
Bottom tank code – DC, BK or BG.
- DC seen on unit dated J (Sept. 1965, year verified).
- DC seen on unit dated M (Dec. 1965, year verified).
- BK seen on unit dated C (Mar. 1966, year verified).
- BK seen on unit dated K (Oct., believed to be 1966).
- BG seen on unit dated B (Feb., believed to be 1967).
- BG seen on unit dated F (June, believed to be 1967).
NOTE – we need some help on pinning down exactly when this tank code changed.
Core ID tag (??) – Unknown, but should be BG (unverified)- DC seen on unit dated M (Dec. 1965, year verified).
- BK seen on unit dated C (Mar. 1966, year verified).
- BK seen on unit dated K (Oct., believed to be 1966).
- BG seen on unit dated B (Feb., believed to be 1967).
- BG seen on unit dated F (June, believed to be 1967).
NOTE – we need some help on pinning down exactly when this tank code changed.
Source for p/n info –
- 66 AIM, Sec. M35, Pg A-27
- P&A dtd 7-1-66
Courtesy Mike Crown:
- 1966 L35 with manual trans and A/C, AIR, and/or HD radiator;
and L34 with manual trans and AIR (without A/C or HD Radiator):
P/N – 3007622 (this is a “Medium sized” 3-row radiator without finger guard).
Identical to a 3007620 except for absence of finger guard.
B/S code – VZ
No Finger guard
Cap on Driver’s side
Top tank code – UP
Bottom tank code – CS or LY (see 3007620 notes above)
Core ID tag (??) – BG (seen on an original radiator with VZ tag)
Sources for p/n and B/S code info –
Radiator from L35 manual AC car (Photo by Jeff Helms):Identical to a 3007620 except for absence of finger guard.
B/S code – VZ
No Finger guard
Cap on Driver’s side
Top tank code – UP
Bottom tank code – CS or LY (see 3007620 notes above)
Core ID tag (??) – BG (seen on an original radiator with VZ tag)
Sources for p/n and B/S code info –
- Original 622VZ radiator from a 66 L35 with AC, with B/S and P/N tag (picture attached).
- Pic of VZ radiator in a 66 L34 with AIR (courtesy Mike Crown).
- 67 AIM Sec. K19 (AIR) pg A-8. (NOTE – Sec. K19 of the 66 AIM lists p/n 3007619 for L34 and L35. That is an obvious mistake because the 619 is a small block radiator and is smaller than any 396 radiator. This mistake is corrected in the 67 AIM which specifically lists 3007622.)
- There is no listing in Sec. C60 or Sec. V01 of the 66 AIM for the p/n of the HD unit applicable to an L35 with manual trans. However, 3007620, 3007621 and 3007623 are all listed, and this is in the proper sequence (both as to p/n and B/S code VZ for p/n 3007622 versus VX for 3007620).
- Pic of VZ radiator in a 66 L34 with AIR (courtesy Mike Crown).
- 67 AIM Sec. K19 (AIR) pg A-8. (NOTE – Sec. K19 of the 66 AIM lists p/n 3007619 for L34 and L35. That is an obvious mistake because the 619 is a small block radiator and is smaller than any 396 radiator. This mistake is corrected in the 67 AIM which specifically lists 3007622.)
- There is no listing in Sec. C60 or Sec. V01 of the 66 AIM for the p/n of the HD unit applicable to an L35 with manual trans. However, 3007620, 3007621 and 3007623 are all listed, and this is in the proper sequence (both as to p/n and B/S code VZ for p/n 3007622 versus VX for 3007620).
Radiator in L34 manual with smog (Courtesy Mike Crown):
- 1966 L35 with PG and A/C, AIR, and/or HD radiator;
and L34 with PG and AIR (without A/C or HD Radiator):
P/N – 3007623 (this is a “Medium sized” 3-row radiator without finger guard)
Identical to a 3007621 except for absence of finger guard.
B/S code – VK
No Finger guard
Cap on Driver’s side
Top tank code – UP
Bottom tank code – DC, BK or BG. (see 3007621 notes above)
Core ID tag (??) – BG (seen on an original 66 L35 AC radiator)
Sources for p/n and B/S code info –
- 66 AIM Sec. K19 pg A-8 (AIR), Sec. C60 (A/C) pg B-3, and Sec. V01 (HD Rad) pg A-1.
- Original 623VK radiator with B/S and P/N tag, picture attached (P/N is not visible due to the shroud, but I did loosen the shroud and confirm it is stamped 3007623)
Photo by Jeff Helms:Identical to a 3007621 except for absence of finger guard.
B/S code – VK
No Finger guard
Cap on Driver’s side
Top tank code – UP
Bottom tank code – DC, BK or BG. (see 3007621 notes above)
Core ID tag (??) – BG (seen on an original 66 L35 AC radiator)
Sources for p/n and B/S code info –
- 66 AIM Sec. K19 pg A-8 (AIR), Sec. C60 (A/C) pg B-3, and Sec. V01 (HD Rad) pg A-1.
- Original 623VK radiator with B/S and P/N tag, picture attached (P/N is not visible due to the shroud, but I did loosen the shroud and confirm it is stamped 3007623)
Photo by Jeff Helms:
[End Part 2, continued below]
