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Seized Fan Motor Solution?

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Old 11-09-18, 07:17 PM
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Seized Fan Motor Solution?

jw if anyone has found a solution to a seized radiator fan motor? My goal is to not spend 240$ on a new motor for it and see if there are other possibilities. I searched a rebuild post on here but it seemed like that guy had no luck as far as a rebuild solution. But any tips or tricks are greatly appreciated! Or worst case scenario if anyone has an extra one lemme know!
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Old 11-09-18, 08:42 PM
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Go on eBay and purchase a used RX8 fan set for $100 shipped. You will need to splice the electrical connector and swap on your fan blade but the motor itself is a bolt-on
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Old 11-09-18, 09:11 PM
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I had one seize a long time ago after switching to a v-mount. Took it apart and it was dry but otherwise okay; it has bronze sleeve bearings, iirc. Used some high drop point sticky grease to lube it up and it worked fine thereafter; no reason to replace it. Fans had about 200k miles on them at the time it seized. (Note that when you invert the fans for a v-mount, you change the fan's thrust bearing surface and may encounter this problem as it doesn't appear that they were lubed for shaft-up operation from the factory--so I'd recommend opening them up and lubing them as a precaution.)
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Old 11-09-18, 09:46 PM
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Oh wow I did not know the rx8 fan motor would work like that! So is there a difference in right or left? And do I need to take off the whole fan shroud to do this? Iím trying to avoid draining coolant if possible
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Old 11-09-18, 09:47 PM
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Originally Posted by Speed of light View Post
I had one seize a long time ago after switching to a v-mount. Took it apart and it was dry but otherwise okay; it has bronze sleeve bearings, iirc. Used some high drop point sticky grease to lube it up and it worked fine thereafter; no reason to replace it. Fans had about 200k miles on them at the time it seized. (Note that when you invert the fans for a v-mount, you change the fan's thrust bearing surface and may encounter this problem as it doesn't appear that they were lubed for shaft-up operation from the factory--so I'd recommend opening them up and lubing them as a precaution.)
Iíll definitly try and open them up and see what I can see before buying a new one. Worst case scenario I canít break whatís broke, thanks for the info
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Old 11-09-18, 09:57 PM
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Originally Posted by TwinCharged RX7 View Post
Go on eBay and purchase a used RX8 fan set for $100 shipped. You will need to splice the electrical connector and swap on your fan blade but the motor itself is a bolt-on
Eh, not entirely true. You have to swap in the rx8 fans and motors, the blades aren't swappable. And, it has to be an s2 rx8.

https://www.rx7club.com/3rd-generati...x7-fd-1085155/

Originally Posted by ecurbd02 View Post
Oh wow I did not know the rx8 fan motor would work like that! So is there a difference in right or left? And do I need to take off the whole fan shroud to do this? Iím trying to avoid draining coolant if possible
I've done the swap and it's really not worth it. Just get a used FD fan motor and be on your merry way.
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Old 11-09-18, 10:10 PM
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Originally Posted by Narfle View Post
Eh, not entirely true. You have to swap in the rx8 fans and motors, the blades aren't swappable. And, it has to be an s2 rx8.

https://www.rx7club.com/3rd-generati...x7-fd-1085155/



I've done the swap and it's really not worth it. Just get a used FD fan motor and be on your merry way.
what makes it not worth it? Jw
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Old 11-09-18, 11:20 PM
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There's nothing wrong with the stock fans. They work good and last. Probably cheaper to get a used FD motor and pop it in. No splicing or research necessary.

If you want all new everything, then the rx8 motors and fans are much cheaper than new FD motors and fans. The fans and motors are different. No real science on which are better.
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Old 11-09-18, 11:53 PM
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I've done the swap too. If you don't want to pay a lot of money for old fans it is entirely worth it. I actually got my rx8 fans (full set of 2 individual motors) for $40 on eBay. I used $100 in my post above because I haven't checked pricing in the last 18 months since I did mine.

I have no idea why you would say it's not worth it.
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Old 11-10-18, 08:04 AM
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From what I got out of it, is itís the same as 99+ spec rx7, and if splicing wires is gonna be the nose difficult thing that doesnít sound too bad. For an upgrade from stock it may not seem worth it, but if u are needing a replacement, 100$ vs 240+$ sounds better all day long
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Old 11-10-18, 09:31 AM
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You can remove the fans from the radiator without having to drain the radiator. You will need to remove the intercooler, IC duct, battery and battery tray for access.

The fans have 3 10mm bolts that hold them in, the hard part is just removing all the stuff to get down to them!

As stated, a good used set of fans is by far the easiest route. Bolt in, plug in, done. Going with RX-8 or 99 spec fans can upgrade the cooling but there is some more work involved. Read up on it, there's a number of threads on the topic. Also there are more than 1 version of the fans on the RX-8, I believe some of the motors are 2-wire not 4-wire so you have to be sure you are getting the right parts. On a relatively stock car I don't know if you would actually get that big of a difference for the extra work.

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Old 11-10-18, 11:54 AM
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I replaced my RX7's with RX8's on my recent rebuilt. You can buy everything new through Mazda. Motors( have to get the 4-wire version) are around $55 each with typical 30% discount. On fan blade is around $65 and the other is around $75, both with the 30% discount. Everything brand new is around $250 and you are good to go for years to come. Also, the RX8 motors and fans are quieter, more efficient and move more air. I repainted my shroud with plastic paint from Eastwood and painted the new motors black. Just cut of the old plugs, leaving 4-5 inches of wire hanging out, and connect the new wires color for color. Matching the colors is the correct wiring.
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Old 11-10-18, 12:02 PM
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250$ still cheaper than one motor for an rx7 fan 😂 I think Iím gonna go that route. Cheaper, more efficient (even if itís not by much) and more reliable, thereís not much of an argument not too. Gonna search around see what I can find used first. Surprisingly there isnít many of them on eBay at all. But I appreciate the input from everyone!
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Old 11-10-18, 01:42 PM
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You're being hard headed. Just put a used fan in and save yourself some time and money.]

Originally Posted by mikejokich View Post
Also, the RX8 motors and fans are quieter, more efficient and move more air. Mike
Mostly conjecture. I haven't seen any cfm analysis.

Last edited by Narfle; 11-10-18 at 01:46 PM.
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Old 11-10-18, 03:22 PM
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Itís stil 100$ vs 240$, prob take a half hr longer to replace with the rx8 fans, splicing, soldering and heat shrink doesnít take any time at all. Whether itís actually more efficient or quieter Iím not really worrried about. Just as long as I get the equivalent or greater to stock performance. But youíre correct, I havenít seen any cfm analysis of the rx8 fans. Or I just havenít looked hard enough
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Old 11-10-18, 04:10 PM
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Originally Posted by Narfle View Post
You're being hard headed. Just put a used fan in and save yourself some time and money.]



Mostly conjecture. I haven't seen any cfm analysis.
IMO, not totally conjecture. Yes, I didn't use a db meter before and after replacement, but subjectively the RX8 blades are quieter that the RX7 blades. Most everyone I have read who has done it agrees. Others can weigh in. The RX8 blades weigh less than the RX7 blades by about 30-40 grams if I remember correctly. The RX7 blades weigh around 230-240 grams as I remember. In general, less weight (mass), more speed with equivalent motors without taking into account the blade design and subsequent friction and drag. The more important factor however is the blade design. The RX7 blade is a dated design with a sharp elliptical edge on the lead portion of the blade. The newer RX8 blade looks like all of the other current blade designs seen on Spal fans and other current automotive aftermarket and OEM fans. This is not a random thing, it is because this design is superior to the older design. IMO, I know this also because two of my good friends here in Huntsville are Aerospace engineers for Boeing and one of them used to work for GE on jet/turbo fan designs many years ago and we have discussed this while I was redoing my fans. I didn't do an amperage comparison and I cannot confirm less amperage draw but based on the fan weight alone, it should draw less (less mass to move), again not accounting for blade design. Lastly. I also didn't do a CFM analysis. I don't have the necessary high-end testing equipment. If someone does, I would like to see it.
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Old 11-10-18, 04:48 PM
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Maybe the motor is weaker because the blades are better. Maybe it was a cost redesign. There's no evidence they're better, and there's no deficiency with the stock unit. Why are we putting incorrect parts in our car for no good reason? Speculation and superstition.

Introducing foreign parts and amateur wiring provides plenty of opportunity for failure and frustration. It took more than zero effort to do the swap. I pin swapped the connectors and replaced all the hardware that doesn't come with th fans. Solder or butt splices will work fine.

The stock part is so mindlessly effective, correct, and available I just don't understand why you'd do anything else.

FWIW, the rx8 fans seem to cool my rx7 fine. I run a real stock car, with a RD radiator, in the west coast heat without issue. I guess they look cool and weigh less. I wonder intermittently how they are performing relative to the stock fans. Not notably different from the seat of the pants.

God speed with the swap. But, if you're on the fence about it, then here's your counterpoint.

It would be rad if someone could do rpm and cfm analysis on the blades and motors.

Last edited by Narfle; 11-10-18 at 04:52 PM. Reason: typo
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Old 11-11-18, 09:38 AM
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Originally Posted by mikejokich View Post
...I didn't do an amperage comparison and I cannot confirm less amperage draw but based on the fan weight alone, it should draw less (less mass to move), again not accounting for blade design. Lastly. I also didn't do a CFM analysis. I don't have the necessary high-end testing equipment. If someone does, I would like to see it.
Mike
More amperage would be required only to get the blade up to speed due to its higher weight (rotational inertia). But once it's moving, weight/inertia makes almost no difference in required power. It's the same as a heavier car or heavier flywheel - slower acceleration, but top speed is hardly affected by the weight.

Last edited by DaveW; 11-11-18 at 09:46 AM.
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Old 11-11-18, 04:49 PM
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Is it possible to take the fans out without disconnecting the radiator hose? Cuz the ac thingy is in the way in the other side



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Old 11-11-18, 05:35 PM
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Usually the fans are installed with the radiator, which is usually removed from below by disconnecting the hoses and sway bar mounts. Either way, it looks like that hose has to come off.
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Old 11-11-18, 05:46 PM
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Originally Posted by Narfle View Post
Usually the fans are installed with the radiator, which is usually removed from below by disconnecting the hoses and sway bar mounts. Either way, it looks like that hose has to come off.
i was trying to avoid that but I guess itís not a huge deal, I have the fans loose, thatís just whatís in the way lol
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Old 11-11-18, 10:53 PM
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Once the radiator hose is moved or removed, you can take them off without removing the radiator. It takes some maneuvering but it works. That's how I got mine off and on.
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Old 11-11-18, 11:32 PM
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I did the Rx8 fan swap, it's completely worth it for the noise reduction and efficiency. I have a few extra new male and female connectors for the rx8 fans if anyone needs a set for a couple bucks plus shipping. Also have a working motor from my rx7 fans i pulled off when i swapped if you'd rather just swap it out and be done.
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Old 11-12-18, 02:22 AM
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Originally Posted by npcrs32 View Post
I did the Rx8 fan swap, it's completely worth it for the noise reduction and efficiency. I have a few extra new male and female connectors for the rx8 fans if anyone needs a set for a couple bucks plus shipping. Also have a working motor from my rx7 fans i pulled off when i swapped if you'd rather just swap it out and be done.
now ya tell me, I just ordered 2 rx8 fans/ motors 😂 oh well, Iíll have a spare just Incase
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