The Chevrolet Camaro Radiators.

Source of the article: camaros.org
Author: Kurt Sonen

Radiator Tag Decoding

All Original radiators had metal tags clipped to the header plate of the radiator core, next to the passenger side end tank. (When the end tank was attached, the solder would often also solder the tag to the radiator.) The tags were painted at the same time as the radiator and thus should be gloss black. These tags identify the radiator via a large-font broadcast code - a two-letter code that was used by the assembly plant to identify parts on the assembly line. Also stamped on the bottom edge of the tag, in a smaller font, was the radiator part number. The 1967 tags just had the broadcast code and the part number on it.

1967 UA and UN Tags

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. Note that with both 1967 and 1968/1969 tag formats, the radiator part number may not visible when the radiator shroud is installed and this number can be hard to read due to the size and the depth of the stamping. The 1969 ZH image below illustrates the various codes stamped on the tag, including the part number on the bottom edge of the tag.

1969 ZH Tag

The end tank codes were used by the radiator assembly plant to identify the different tank designs and use them in the correct radiator assembly. The month code (letters A through M format, excluding I) is stamped on the RH end tank between the letters of the tank code. The tank codes and applications are shown in the table below.

A 1969 small block automatic transmission radiator tag in the installed position on the radiator is shown below; the tag tells us that the ZA radiator should have IH and OF end tanks. To the left of the tag is the OF tank code and between the O and the F is the month code, a C (for March). To the right of the tag is the clip to hold the overflow hose from the radiator cap.

1969 ZA Tag

Radiator Application Data, Codes, and Part Numbers

The following application data for the original radiator usage and broadcast codes was assembled from Chevrolet documentation, original cars, and vehicle broadcast sheets. Note that the service part numbers listed in GM parts manuals often superceded the original part numbers listed below.

Table cells colored in blue denote verified data (via cars or broadcast sheets), while the data in uncolored cells come from GM documentation. Cells colored in yellow denote assumed data based on GM documentation that suggests the listed usage. We would appreciate help with increasing the number of table cells that are confirmed via data from original cars.

In several applications, radiator usage changed during the production year; in those cases all usage codes are noted in the table. It is not clear if these changes were due to a purposeful engineering change or a temporary substitution due to a component shortage, but on the table they are noted based on time, i.e. as early or late production.

Note: the late 68 L30/L48 V01/AC radiator is indicated in GM documentation to change from the 23" version to the 21" 3010178 (manual) and 3010179 (auto) radiators. These usages have not been verified. In fact, a late production 1968 manual car with V01 has been documented with the 21" 3017132 ZB radiator. This would suggest the radiator size did change to 21" on these applications, but that GM documention is incorrect on which radiator was used.