Ford radiator cooling fan clutches are identified by basic part number 8A616. Fan clutches are used on fixed-pitch fans to control fan spin based on temperature and engine RPMs. The clutches contain a viscous silicon-based oil which gets pumped in and out of an internal drive area depending on engine RPMs. A bi-metallic spring/switch operates a control valve that regulates the amount of oil flowing within the pump. Here's a table describing fan clutch applications and engineering numbers:
| Application | Service Part Number | Engineering Part Number |
|---|---|---|
| 1968 | C8OZ-8A616-B | C8OE-B C8OE-C |
| 1969 | C9ZZ-8A616-A | C9ZE-B |
| 1970 before 1 September 1969 | C9ZZ-8A616-A | C9ZE-B |
| 1970 from 1 September 1969 | D0ZZ-8A616-A | D0ZE-A |
Here are front and back pictures of the C8OE-B and C8OE-C fan clutches (images courtesy of Jack Wofford):
Here are front and back pictures of a restored C9ZE-B fan clutch (note the engineering number on the mounting flange):
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| C9ZE-B Fan Clutch | C9ZE-B Engineering Number Detail |
The 1970 D0ZE-A clutch isn't very common and is very hard to find today. Here's a series of pictures of one that recently surfaced in New Old Stock condition, including a comparison to a C9ZE-B clutch:
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| D0ZE-A Fan Clutch | D0ZE-A Engineering Number Detail |
D0ZE-A and C9ZE-B Fan Clutches
Bill Upham of Mansfield Restoration Parts was kind enough to share the pictures of the D0ZE-A clutch shown here. He compared the C9ZE-B and D0ZE-A clutches side-by-side and has this to say about the differences:
"After viewing the 2 together the only thing I noticed was that the thermal spring is installed in the opposite direction when compared to the C9ZE-B shown, but I do not think that it makes a difference. I believe the difference between the C9ZE-B and the DOZE-A is in the calibration of the thermal part for whatever reason."
Loss of fluid and subsequent bearing damage is a frequent problem with these fan clutches as they age. Fortunately they can be professionally restored by a company named Kirkconnell Corvettes; contact the company directly for details.
Notice the ink stamp (18IC, 123J above; A27J below) that's visible on some of the clutch pictures shown here. I'm not sure how to decode it, though at least part of the stamp appears to follow Ford's date code format.
Image courtesy of Brandon Badell.
Certain aftermarket clutches made by Hayden (catalog available on their web site) will fit. Hayden part number 2765 (1.09" shaft, 3.25" bolt circle diameter, 7.20" diameter clutch body, 2.67" overall height) will fit with the C9ZE-E fan. Hayden part number 2711 (1.40" shaft, 3.00" bolt circle diameter, 7.20" diameter clutch body, 2.98" overall height) will fit with the C8OE-B fan. Hayden part number 2710 (1.75" shaft, 3.00" bolt circle diameter, 7.20" diameter clutch body, 3.33" overall height) will also fit with the C8OE-B fan, but it's 0.35" taller than the 2711 clutch (and 0.58" taller than the OE C8OE-B and C8OE-C clutches), so it may or may not fit depending on the thickness of your radiator. The 2765 clutch will NOT fit on the C8OE-B fan, and the 2710/2711 clutches will NOT fit on the C9ZE-E fan due to differences in the fan bolt circle diameter.
Here are two pictures (picture 1, picture 2), courtesy of Jim Woods, that show the 2765 clutch compared to the C9ZE-B clutch.