Going over some old items I found this 5 bladed 18" fan blade and the spacer appears to be part of the assembly. I tried to separate then as I thought the aluminum space was ceased to the fan. It did not come apart and I did not force it. Has anyone seen one like this before? Is there a specific application for it."
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The pictured fan is a flex fan, but is not a Chrysler flex fan. Chrysler flex fans typically have five blades, although one seven blade version was made, the blades are fastened with four or six rivets, and the mount is with four bolt holes only. The pictured fan is an aftermarket version, or possibly another car brand. The attached spacer is not a Chrysler spacer.
The Chrysler flex fan was introduced in 1970 in C-bodies with 318 engines and high gear ratio (numerically low) rear axles. The fans had limited use at first, but spread across body lines to be used with all eight cylinder engines, except 340, depending on the application, and were later introduced in six cylinder applications as well.
Chrysler flex fans were built with a steel core frame and blade fastener support with riveted stainless steel blades. Most fans employed an asymmetrical five blades pattern with some variance in pitch and diameter depending on the part number. The flex fan provided a less expensive, and less complex, alternative to the fluid drive, or clutch, fan. It offered similar air movement performance and lower drag than a fixed fan like the fluid drive fan. It is quieter than a fixed blade fan, but not as quiet as a fluid drive fan.
In 1977, use of flex fans, particularly the 20" version, was expanded across the car lines and engines. The following images show the announcement of broader flex fan use and a description of the fans from the 1977 Service Highlights:
Several different fan sizes and configurations for varied applications were used in the 1970s and early 1980s, including those shown in the following table:
| Part Number | Diameter | Blades | Rivets | Notes |
| 3462109 | 18.25” | 5 | 4 | 1970 318 C-body. 2.71 or 2.76 axle ratio |
| 3462150 | 18.25” | 5 | 4 | 1971 318 B/C/E-body. 2.71 or 2.76 axle ratio |
| 3462139 | 18.5” | 5 | 4 | 1973 318 B/C/E-body. 2.71 or 2.76 axle ratio. 360 C-body. 400, 440 B/C-body various. 1974 (trucks). |
| 3462190 | 20” | 5 | 6 | 1974 318 B-body manual transmission.
318 A/E-body. 400,440 B/C-body various. 1974 (trucks). Blades have additional support. |
| 3870107 | 18” | 7 | 4 | 1974, sound control. Cars & trucks. |
| 4071034 | 18” | 5 | 4 | 1977 Cars & trucks. |
| 4117083 | 20” | 5 | 6 | 1978 (trucks), 1979 (cars) |
| 4117104 | 18.5” | 5 | 4 | 1978, sound control. Cars & trucks. |
NOTE: listed dates and applications are generally the first year of usage.
Like fixed blade fans, the flex fans were mounted to the water pump flange with four bolts and a centering hole and a spacer of various depths depending on application. The following image shows Chrysler fan spacers:
For more information about Chrysler fan spacers, see
Chrysler Fan Spacers.
The following image shows three Chrysler flex fans:
- 20" 3462190
- 18" 3462109
- 18" 3462150
The following image shows a 20" 3462190 fan, with additional support/stiffeners for the blades, front and rear:
The following image shows the
3870107 seven blade flex fan:
After 1981, flex fans use in cars was dropped, but remained in trucks for a time longer.
A five blade fan for fluid drive was also used in some production car and truck applications starting in the latter 1970s. Although five blades, these were fixed, not flexible blades. The five blade design offered relatively high efficiency and relatively low drag. Coupled with the fluid drive yielded additional low drag and less noise while maintaining high efficiency of the five blade asymmetric design. The 4140063 production fan was also used in the Mopar Performance P4120758 Viscous Fan Package, which include a thermal fluid drive clutch, part number 4095704.
The following image shows the 4140063 five blade non flex fan for use with a fan clutch:
The following list includes the five blade fluid drive fans:
- 4140063 18” Production ~1977. Also used in Mopar Performance P4120758 kits.
- 4140442 18.5”
- 4266059 18.5”
