Blower Motor Fan - What goes Here?

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1973 Q code Mach 1 blue glow with argent stripes, 351C-4V, C6 auto
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I am refurbishing my heater box on the 73 Mach 1 (no AC). I removed the blower motor fan to find a big hole in the body of the motor where it looks like there should be a plug. I looked inside the heater box and didn't see anything in there except leaves and dirt. Does anyone have a picture of a blower motor that has a plug in it so I can tell what I need to look for? This is a late 1973 production car so maybe they ran out of plugs by the time my car was built on 7/5/73. Here are a couple of pics;
73 Fan.jpg
Fan Date.jpg
 
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Hello Steve,
That hole was in all the blower motor housings with no plug used. Since these motors were usually run at a medium or high speed in a very confined area, they generated a lot of motor heat. The hole is a cooling hole for the motor heat. That heater-only motor is a Fairlane/Torino sourced part used in '65-71 Fairlane, Torino, '66-70 Falcon, and '71 Mustang built before 4/2/71. The before motor is a balanced motor/squirrel cage assembly. After 4/2/71, the motor (with a new part number), squirrel cage, and retaining clip were separate pieces.
The picture below is a NOS C9OZ-18527-B motor/cage assembly with an unplugged hole. :)
 

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swice

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Before you reinstall lubricate with F type transmission oil, mine has stayed quiet for over a year since I added to the vent hole in the housing.
 
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Hello Steve,
That hole was in all the blower motor housings with no plug used. Since these motors were usually run at a medium or high speed in a very confined area, they generated a lot of motor heat. The hole is a cooling hole for the motor heat. That heater-only motor is a Fairlane/Torino sourced part used in '65-71 Fairlane, Torino, '66-70 Falcon, and '71 Mustang built before 4/2/71. The before motor is a balanced motor/squirrel cage assembly. After 4/2/71, the motor (with a new part number), squirrel cage, and retaining clip were separate pieces.
The picture below is a NOS C9OZ-18527-B motor/cage assembly with an unplugged hole. :)
Thanks for that info Steve - that makes sense. What's odd is that I found a body plug under the carpet laying loose that fits in that hole perfectly so I thought it may have fallen out somehow. Just curious about the part number. You say that after 4/2/71 the motor got a new part number. Why was it still a 1969 part number (C9O) as opposed to a D1O?
 
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Before you reinstall lubricate with F type transmission oil, mine has stayed quiet for over a year since I added to the vent hole in the housing.
Are you talking about Type F trans fluid in the bearing of the fan motor? I tested this motor on the bench and it runs very quiet. I was surprised to see 80% of the brush material still there (car has 98,900 miles). The inside of the motor housing looks very clean too.
 
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Thanks for that info Steve - that makes sense. What's odd is that I found a body plug under the carpet laying loose that fits in that hole perfectly so I thought it may have fallen out somehow. Just curious about the part number. You say that after 4/2/71 the motor got a new part number. Why was it still a 1969 part number (C9O) as opposed to a D1O?

Without drowning you in a sea of numbers, I will try just to hit the high spots. The part number and engineering numbers are two different entities. There will never be an actual part number permanently stamped, molded, or otherwise affixed to any production installed or service parts. Service parts will be boxed with a number on a decorative or corrugated carton or applied with a tag or sticker. These parts actually belong to the respective engineering dept that designed them. In this case, that would be the climate control group that usually has numbers in the 18-19K range. The various engineering departments have the final say in which parts are released for service. Parts and Service then assign part numbers which usually are very close to the original engineering number.
This heater blower number has some earlier part numbers since it fits some pre '71 applications. Since I said I would try not to let this turn into a number salad, I will keep to '71-73 applications. The before 4/2/71 motor part number is C9OZ-18527-B (ID# C9OA-18565-B, C). The after 4/2/71 is D1OZ-18527-A but kept the "C9" prefix. The prefix and basic number changed slightly to C9OF-18527-B, which indicates that your motor is the correct D1OZ "after" motor. There were some later D2OF and D3OF ID# prefix revisions, but the D1OZ-A part number remained the same. Ford eventually replaced the D1OZ number in the '80s.
Now you know more than you thought you would ever need or want to know about blower motors!! 😃
 

swice

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Are you talking about Type F trans fluid in the bearing of the fan motor? I tested this motor on the bench and it runs very quiet. I was surprised to see 80% of the brush material still there (car has 98,900 miles). The inside of the motor housing looks very clean too.
yes, I experimented with different lubricants, none held up except F type trans oil. I never removed the blower, I just infused 1/4 cup into the blower by way of a small tube that I worked into the vent hole on top of the blower, on low speed I slowly pumped by hand about 1/4 cup, the noise stopped immediately, it's been over a year and it's extremely quiet and strong. Smell went away in a couple days.
 
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Without drowning you in a sea of numbers, I will try just to hit the high spots. The part number and engineering numbers are two different entities. There will never be an actual part number permanently stamped, molded, or otherwise affixed to any production installed or service parts. Service parts will be boxed with a number on a decorative or corrugated carton or applied with a tag or sticker. These parts actually belong to the respective engineering dept that designed them. In this case, that would be the climate control group that usually has numbers in the 18-19K range. The various engineering departments have the final say in which parts are released for service. Parts and Service then assign part numbers which usually are very close to the original engineering number.
This heater blower number has some earlier part numbers since it fits some pre '71 applications. Since I said I would try not to let this turn into a number salad, I will keep to '71-73 applications. The before 4/2/71 motor part number is C9OZ-18527-B (ID# C9OA-18565-B, C). The after 4/2/71 is D1OZ-18527-A but kept the "C9" prefix. The prefix and basic number changed slightly to C9OF-18527-B, which indicates that your motor is the correct D1OZ "after" motor. There were some later D2OF and D3OF ID# prefix revisions, but the D1OZ-A part number remained the same. Ford eventually replaced the D1OZ number in the '80s.
Now you know more than you thought you would ever need or want to know about blower motors!! 😃
Great information Steve - thanks. By the way, I am an engineer by trade so I am familiar with engineering numbers versus part numbers used on released drawings. So based on what you said above, all of the numbers I see on every part in my Mustang (i.e. D3Z... etc) are better referenced as engineering numbers and the Z in the third character are parts that are specific to the Mustang?
 
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Steve, Glad to hear that you are an engineer and familiar with these number salads. I worked with these numbers for many years, so I'm used to what can be a confusing and challenging number system for some. It is Ford's corporate policy on no actual part numbers on OE or service parts. As posted earlier, these parts belong to the department that designed/engineered them. They also decided which ones were to be released as a service part or not and if a complete assembly or separate components. The engineering numbers you see on the various parts on your car are primarily for internal use in the assembly plant and on the production line. Secondary use was for the dealer/parts dept to use and help identify all the mind-numbing combinations of trims, colors, and never-ending running changes on the assembly line that the catalogs never kept up with.
In the case of the heater-only blower number, the Fairlane group was tasked with designing that piece. The motor started life with the new '62 Fairlane, which explains where the prefix's third digit "O" comes from. The subsequent part number changes continued with the "O" until the 1980 Fairmont "E0BZ" replaced it. Parts sharing, where possible, helps with cost allocation between the various car and truck lines. Such as the D1TZ-17618-B windshield washer reservoir used on the '71-73 Mustang. This reservoir is a truck part with "T" in the third digit of the prefix and was utilized from '71-79 on the F100-350. The majority of the "Z" parts are Mustang specific. :)
 
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