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CRG Research Report

1967-69 Camaro Cooling Systems

(including radiator and fan usage)

© 2004-2017, Camaro Research Group

Author -
Reviewed by the CRG
Last Edit: 11-Nov-2017
Previous Edits: 19-Sep-2014, 15-Oct-2011, 04-Apr-2008, 24-Feb-2007
Original Release: 06-May-2004



This article describes the original components and applications for 1967-1969 Camaro cooling systems, including radiators, radiator tanks, fan shrouds, and engine cooling fans. It addresses how engine, transmission type, and two options - the V01 heavy duty (HD) radiator option and the C60 air conditioning (AC) option - affected radiator and cooling fan selection by the factory. Note that the information presented here applies specifically to Camaro.

All first-generation Camaro radiators were manufactured by the Harrison Radiator Division of GM and were of the cross-flow design type (as opposed to earlier vertical flow designs). Hot coolant from the engine enters the upper left-hand side of the radiator and is cooled as it passes through the radiator core, exiting the lower right-hand side into the waterpump (RH and LH as observed from the driver's position).

The basic cooling system design is robust and with proper maintenance, will last for years. See JohnZ's Cooling Basics for practical information about the proper functions of the components and system.

Radiator Variables

Design variables in Camaro radiators included core thickness (number of rows in the core: 2, 3, or 4), core width (21-inch or 23-inch), and core fin spacing. Radiator heat rejection capacity improves as core thickness and width increases and as core fin spacing decreases. It is believed that all first gen Camaro radiators had copper/brass cores. Some GM documentation indicates that some small block radiators had aluminum cores, but there is no further evidence to support that assertion. All radiators were painted gloss black and had the mounting brackets soldered onto the radiator end tanks.

Radiators for cars with automatic transmission included a transmission oil cooler in the passenger side end tank; manual transmission radiators did not have this provision. The fin spacing is also smaller for automatic radiators (smaller fin spacing increased the radiator's heat rejection capability) to compensate for the increased heat input from the automatic transmission. (Note that radiators sold for service use are often generic and include the transmission cooler provision even for manual transmission cars.)

A heavy-duty radiator was available by ordering either of two options. Regular Production Option (RPO) V01 was the heavy-duty radiator option and was available with all engines except the Z28 or big block engines. All vehicles optioned with air conditioning (RPO C60) also received a HD radiator.

Axle ratio did not affect the radiator usage with one (unverified) exception. In the April 1 1969 revision of the dealer ordering information, it states that Positraction Rear Axles: Ratios 3.73 or 4.10 without Special Performance Package (Z28) or 396 engine "also includes HD radiator" and the MSRP is $56.90. This means that a SS350 (or L65 or 307) with 3.73 or 4.10 gears would automatically get the V01 radiator. This would also apply to COPO 427 cars (and the higher price showed up on some later COPO window stickers), but they already received a 4 core radiator as part of the COPO package.  

Radiator Usage

The standard radiator for L6 and small block V8 engines was a 2-row core (1.26-inches thick) that was 21-inches wide.

On all 1967-9 L6 cars, adding RPO V01 or AC resulted in use of a radiator that differed from the standard part only by the use of a smaller fin spacing.

For 1967 and 1968 small blocks, adding V01 or AC increased the radiator from a 2-row core to a 3-row core (1.98-inches thick). The V01 or AC radiators for the 67-68 L30 and L48 engines also received a wider 23-inch wide 3-row core. But in late 68, the AC or V01 radiators for L30 and L48 engines changed to a 21-inch core instead of a 23-inch core. We don't know the reason for this application change, but it was consistent with the upcoming 69 usage.

For 1967 big block engines, AC was not a factor in radiator selection since the SS396 was not available with AC in 1967. For 1968 big blocks, AC was an available option for the L35 and L34 engines and increased the radiator from a 3 core to a 4 core (2.70 inches thick). Note that this was a straight neck radiator, unlike the 69 curved neck radiators that used the same broadcast code.

For 1969, all small block radiator cores were 21-inches wide and all big block cores were 23-inches wide. On 1969 small-block engines, adding V01 or AC increased the size of the radiator core from 2-rows to 3-rows. Addition of AC to 1969 big-block engines increased the number of radiator core rows from 3 to 4 and added a curved inlet neck in order clear the 1969 AC components. 1969 COPO 427's (see CRG COPO Research Report) also used this same curved-neck 396/AC 4-row core radiator - eliminating the need for the assembly plant to stock a straight-neck 4-core in 69.

If there was a production shortage (a relatively infrequent event), a larger capacity radiator would be substituted.

The top and bottom plates of the original radiator core for 2, 3, and 4 cored radiators have a unique hole pattern (the top and bottom plates are the same). Research at Harrison Radiator by Tom DeWitt has shown that the adjacent rectangular and square holes near the ends of the top and bottom plates were used by Harrison to hang the assembled radiators on their paint hooks. Most replacement cores do not have these holes. Below are two pictures of original radiator top plates showing the hole pattern.

1969 2-Row Core Top Plate   1968 3-Row Core Top Plate
1969 2-Row Core Top Plate   1968 3-Row Core Top Plate

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
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. Beneath the tank codes, is a 1 or 2 digit number that is believed to identify the radiator core assembly to be used in that radiator.
To the right of the core assembly number is the letter O, R, or S. The meaning of this letter 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
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
ZA rad tag

Radiator End Tank Codes
Side Year Application Tank Code
Left Side 67-69 L6 and SB IH
  67-69 BB except 69 4-row core IL
69 4 core BB (curved neck) IO
Right Side 67-68 L6 and SB manual OD
  69 L6 and SB manual CB
67-69 L6 and SB auto
(exc 67-68 L30/L48 w/ V01 or AC)
67-68 L30/L48 auto w/ V01 or AC - 23" OG
69 LF7/L14 auto w/ V01 or AC
67-68 BB manual OL
67-68 BB auto OM
69 BB manual OO
69 BB auto CH

Radiator Applications

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 original part numbers listed below were often superceded by service part numbers in GM parts manuals.

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. Both radiator codes are noted in the table with a reference to early or late production.

1967-1969 Radiator Applications
1967 Manual Transmission   Automatic Transmission
Engine Broadcast
Part No. Core
Width (in.)
Fin Spac-
ing (in.)
Part No. Core
Width (in.)
Fin Spac-
ing (in.)
L26 UC 3010173 2 21 0.28 UD 3010174 2 21 0.25
L26 HD UE 3010175 2 21 0.16 UF 3010176 2 21 0.16
L22 UA 3010171 2 21 0.22 UB 3010172 2 21 0.22
L22 V01/AC UE 3010175 2 21 0.16 UF 3010176 2 21 0.16
LF7 UG 3010177 2 21 0.20 UF 3010176 2 21 0.16
LF7 V01/AC UH 3010178 3 21 0.16 UI 3010179 3 21 0.16
L30 UG 3010177 2 21 0.20 UF 3010176 2 21 0.16
L30 V01/AC UJ 3010180 3 23 0.18 UK 3010181 3 23 0.18
L48 UG 3010177 2 21 0.20 UF 3010176 2 21 0.16
L48 V01/AC UJ 3010180 3 23 0.18 UK 3010181 3 23 0.18
Z28 UH 3010178 3 21 0.16 n/a n/a n/a n/a n/a
396 UN 3013684 3 23 0.16 UO 3013685 3 23 0.16
1968 Manual Transmission   Automatic Transmission
L26 UC 3010173 2 21 0.28 UD 3010174 2 21 0.25
L26 HD UE 3010175 2 21 0.16 UF 3010176 2 21 0.16
L22 UA 3010171 2 21 0.22 UB 3010172 2 21 0.22
L22 V01/AC UE 3010175 2 21 0.16 UF 3010176 2 21 0.16
LF7 UG 3010177 2 21 0.20 UF 3010176 2 21 0.16
LF7 V01/AC UH 3010178 3 21 0.16 UI 3010179 3 21 0.16
L30 UG 3010177 2 21 0.20 UL 3016782 2 21 0.18
L30 AC/HD UJ* 3010180 3 23 0.18 UK 3010181 3 23 0.18
ZB** 3017132 3 21 0.18
L48 UG 3010177 2 21 0.20 UL 3016782 2 21 0.18
L48 V01/AC UJ* 3010180 3 23 0.18 UK 3010181 3 23 0.18
ZB** 3017132 3 21 0.18
Z28 UH 3010178 3 21 0.16 n/a n/a n/a n/a n/a
396 UN 3013684 3 23 0.16 UO 3013685 3 23 0.16
396 AC UY 3016688 4 23 0.16 UZ 3016689 4 23 0.16
1969 Manual Transmission   Automatic Transmission
L26 UC 3010173 2 21 0.28 UB 3010172 2 21 0.22
L26 HD UE 3010175 2 21 0.16 UF 3010176 2 21 0.16
L22 UC 3010173 2 21 0.28 UB 3010172 2 21 0.22
ZA 3016719 2 21 0.20
L22 V01/AC UE 3010175 2 21 0.16 UF 3010176 2 21 0.16
L14 UA 3010171 2 21 0.22 ZA* 3016719 2 21 0.20
UL** 3016782 2 21 0.18
L14 V01/AC ZB 3017132 3 21 0.18 ZC 3017131 3 21 0.18
LF7 UA 3010171 2 21 0.22 ZA 3016719 2 21 0.20
LF7 V01/AC UH 3010178 3 21 0.16 ZC 3017131 3 21 0.18
LM1 UG 3010177 2 21 0.20 UF 3010176 2 21 0.16
LM1 V01/AC UH 3010178 3 21 0.16 UI 3010179 3 21 0.16
L65 UG 3010177 2 21 0.20 UF 3010172 2 21 0.16
L65 V01/AC UH 3010178 3 21 0.16 UI 3010179 3 21 0.16
L48 UG* 3010177 2 21 0.20 ZA* 3016719 2 21 0.20
ZH** 3020093 2 21 0.18 ZI** tbd 2 21 tbd
L48 V01/AC US 3014187 3 21 0.20 UR 3014186 3 21 0.20
Z28 UH 3010178 3 21 0.16 n/a n/a n/a n/a n/a
396 ZD 3017837 3 23 0.16 ZE 3017838 3 23 0.16
396 AC UY 3018624 4 23 0.16 UZ 3018623 4 23 0.16
COPO UY 3018624 4 23 0.16 UZ 3018623 4 23 0.16
*early production     **later production Blue is Confirmed Data
Yellow is Assumed Data

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, two late production 1968 manual cars with V01 have 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.


Radiator Shroud Usage and Part Numbers

The following are the part numbers for the plastic fan shrouds that were used in conjunction with the above listed radiators. L6 engines without AC or V01 did not have a shroud, just a small metal shield attached to the radiator support. The L6 engine radiator shroud applications are taken from the 1969 Chevrolet Parts Manual. It is unclear why only some L6 HD radiators were listed as receiving a shroud, those applications are shown in the table below.

Fan Shroud Part Numbers
Year Application Part Number Notes
67-68 SB (except L30/L48 w/ V01 or AC) 3893812  
67-68 L30/L48 w/ V01 or AC 3893814 23 inch
67-68 BB 3916637  
69 SB 3938615  
69 BB 3947619  
67-69 L6 w/o V01 or AC no shroud used shield 3893892
67-69 L6 with AC 3893816  
67 L6 with smog w/o AC
67-68 L26/manual with V01

Radiator Cooling Fans

A fixed four-blade fan was the standard engine fan on all engines. There were two exceptions: the solid-lifter engines (Z28, L78, and COPO 427) and vehicles with AC used a temperature-controlled clutch fan as standard equipment.

The temperature-controlled clutch fan was also available as option K02 on the hydraulic-lifter engines for $15, but only 4712 1967-69 Camaros were ordered with this option. Air conditioning (RPO C60) included the K02 clutch fan as part of the AC package. The V01 HD radiator option did not affect the fan usage.

Out of 400,000 non-AC V8 cars that could have the optional clutch fan ordered, only 1% of them had the option. Even if most of these clutch fans were installed on non-L78 SS cars (not very likely), under 5% of those SS cars would have them. So yes, your SS350 or SS396 (325hp or 350hp), if without AC, likely came with the standard four-blade fixed fan.

The 1967 and 1968 V8 engines used the short water pump design and the bolt circle diameter to mount the fan on the water pump is 1.75". In 1969, as part of the V8 engine layout standardization, the water pump was changed to the long design and the water pump bolt circle diameter was changed to 2.30".

Fixed (Non-Clutched) Four-Bladed Fans

The standard fixed four blade fan was 3839282 for the 1967-68 model years. It changed to 3927791 for the 1969 model, with one source indicating that 396 cars received the 3947890 fan. It is unknown what the difference is between the two 1969 fans.

There were a number of different length spacers to mount the fixed four-blade fan to the waterpump, as shown in the table below. The lengths noted are the spacer length and exclude the fan locator / pilot.

Four-Bladed Fixed Fan for 67-69
1969 four-bladed fan
Four-Bladed Fan Spacer Part Numbers
Year Application Part Number Length (inch)
67-68 6 cyl. 3876828 2-9/32
67 V8 (exc. 396) 3814241 1-15/16
68 V8 (exc. 396) 3857041 1-17/32
67-68 396 3857042 1-9/32
69 6 cyl. 3927794 1-1/2
69 V8 3927792 1

3876828 Spacer for Four-Bladed Fan
3876828 fan spacer
3927792 Spacer for Four-Bladed Fan
3927792 fan spacer

Clutch Fans

The fan spacing on the clutch fans was staggered to help reduce harmonics (and thus noise). The clutch limited the maximum speed the fan could spin, effectively acting as a rev limiter for the fan, reducing noise and fan power consumption.

A variable in the clutch applications is the distance of the fan mounting surface to the waterpump mounting surface distance. This distance is normally different between small block and big block applications with the big block clutch having a shorter shaft to properly position the fan fore-aft relative to the fan shroud. There were at least three different clutch suppliers. It is believe that the redline of the engine was a factor in which clutch was used on an engine. Fan clutches often have the date (Julian date and year) and part number stamped on the waterpump mounting flange.

In 1967 and 1968, the clutch fan was 18 inches in diameter, most had five blades (there was limited usage of a seven blade fan, see below), and came in two types:

Fan for AC or K02 cars
For 1967 cars with hydraulic lifter engines with AC or K02, the 3789562 fan or the 912239 fan was installed. For 1968 cars with hydraulic lifter engines with AC or K02 (except 1968 L34/L35 with K02), the 3789562 fan or the 3931002 fan was installed. The 3931002 is a seven blade fan with limited observed usage on Camaros; it has so far been found on some LF7 (327/210hp) cars with air conditioning. All three fans have a 3-inch diameter clutch-to-fan attachment bolt circle.
Three different fan clutch part numbers are listed as having been used with these fans, all having the 3-inch diameter bolt circle. For 67: 3916139 and 3916140. For 68: 3916139, 3916140, and 5329100.

Fan for L78 and Z28 and 1968 L34/L35 with K02
The 3871276 fan was used on the 1967 and 1968 Z28 and L78, as well as 1968 L34/L35 with K02. The bolt circle diameter for the clutch-to-fan attachment was 3.25-inch. It thus required a different clutch unit than the fan clutches used with the AC or K02 hydraulic lifter engines. The 67-68 Z28 and the 68 396 cars used the 3927103 Switzer-supplied clutch unit. The parts manuals list the 67 L78 clutch as 3916141, but this usage has not been verified.

Five-Bladed Fans for 67-68
(Note the difference in the center hole diameter.)
3789562 fan   3871276 fan
3789562 fan, NOS   67-68 Z28 clutch fan

In 1969, the clutched fan changed to a seven-blade design (still 18 inches in diameter) with aluminum fan blades. Cars with AC or K02 received the same fans as the 1969 Z28 and L78/COPO cars. There were two manufacturers of this fan and a mid-year fan pitch change (2 to 2.25"), yielding four variants of this fan.

From what has been observed on original cars, the 3947772 fan and the unstamped fan were used interchangeably and with approximately equal usage. As noted above, the 3937779 fan was only used on early 69 cars.

3947772 Seven-Bladed Fan for 69
3947772 fan   Close-up of Dec 68 3947772 fan

'Unstamped' Fan   3937779 Fan Close-up
Unstamped fan   779 fan, close-up of blade and hub

In 1969, 3 different fan clutches were used for C60 (AC) and RPO K02 cars (except 396). The AIM lists the part numbers as 3937780, 3937782, and 4939899; the service part was 3937781. These clutches have been observed to be Delco clutches, stamped with the broadcast code of CH.
The L35/L34 396 cars with C60 or K02 used a 3946049 clutch. (The AIM shows this was also used for 350 ci engines, but that is not what has been observed in cars).
The L78/COPO used part number 3946050 (stamped CZ) and the Z28 used 3946804 (stamped CV), both were Eaton-supplied units.

1968 Z28 Fan Clutch   1969 Delco Fan Clutch   1969 Eaton Fan Clutch (CZ code)
1968 Z28 Fan Clutch   1969 Delco Fan Clutch, #4939899   1969 L78/COPO Fan Clutch


The author would like to acknowledge the people who contributed data on their cars, Rich Fields who originally edited and converted this report into HTML, Rick Peters who provided a critical page of GM documentation that was the catalyst for completion of this long-planned Research Report, and David Liukkonen for the details on the 69 clutched fans.

You can help improve future revisions of this report. We would appreciate verification of unconfirmed radiator usages via data from original radiators and cars (or via broadcast sheets). We also would appreciate digital photos of original radiator tags. The tank codes on the 1968-1969 tags will help verify the radiator tank usages.


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