The Chevrolet Camaro Radiators.

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

Radiator Shroud Usage and Part Numbers

The following are the part numbers for the plastic fan shrouds that were used in conjunction with 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.

Radiator Cooling Fan

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. RPO C60 air conditioning included the K02 clutch fan as part of the AC package (while the V01 HD radiator option did not affect the fan usage). So yes, your SS350 or SS396 (325hp or 350 hp), 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.

Four-Bladed Fixed Fan for 67-69

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. Unless otherwise noted, lengths are based on measurement of actual parts; the unconfirmed length is from a parts manual note.

Typical Spacer for 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 2 (unconfirmed) 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

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.

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 matching 3-inch diameter bolt circle.

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.

Five-Bladed Fans for 67-68
(Note the difference in the center hole diameter.)

3789562 fan		3871276 fan

In 1969, the clutched fan changed to a seven-blade design (still 18 inches in diameter). Current research indicates that cars with AC or K02 received the same fans as the 1969 Z28 and L78/COPO cars. There were at least three variants of this fan, all are functionally the same.

• The 3937779 fan was used early in the 69 production year (until approximately November of 68) and has the part number and month / year stamped on the fan blades.
• The 3947772 fan was used throughout the production year (and through the early 70's) and has the part number and month / year stamped on the fan blades.
• An unstamped fan - of unknown part number - was used and is similar to the 772 and 779 fans but with minor design differences (specifically: the design of the center section, details of fan blade rivet attachment, and lack of stamped part number or date). It was used throughout the production year.

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

'Unstamped' Fan		3937779 Fan Close-up