Oil cooler fan (redux)
A few weeks ago I began talking to Quigley, a member of this forum, who has fabricated a cooler-fan setup that included a temperature probe and adjustable switch. The probe fits in place of the oil-pressure sender or with it when installed with a tee. The switch can be placed anywhere, and it allows temperature regulation. The idea is that when the set temperature is reached the fans activate, then go off as the temperature falls below the set value. I'm more of a manual kinda guy and like making my own decisions about such things, so I obtained two of his fans and rigged the same switch and used the same wiring (never removed) that I used in last year's attempt.
I was concerned about moisture, but he tested the fans by emersing them in water repeatedly, and they still worked even when wet. I plan on keeping them turned off unless weather is dry, but these fans are an experiment. We've both tried to find IP55-rated waterproof fans in this size, but couldn't find any with a decent CFM rating. Another probem is that although there are some being marketed we could not find a source for them in small quantities. Time will tell how these hold up to water and dirt, but being behind the cooler I think they have a better chance to survive. He is selling the two fans alone for $25 including shipping, but if you're interested in the whole kit you'll need to contact him for prices and questions.
Anyway, looking at Photo #1 you'll see how I initially secured the fans to the cooler. On the right I looped them around the side of the cooler, but this could not be done on the left without the wire-tie showing and conflict with the hose nipples. Instead, for the left side I pushed the wire-ties through the opening just outside the fins and used the blunt end of the wire-tie to stop it from the front (see Photo #2). The wire-tie continued through only the back left holes in the fan (top and bottom), and were secured on the rear by the blunt end of a second wire-tie. You can see the setup before I cut the excess. The two fans were wire-tied top and bottom together in the center holes, and these dont touch the cooler at all.
Back to the right side, I initially used the loop idea, but then decided for cosmetic reasons to use the same technique as on the left. After it was all installed I cut the looped configuration and ran the wire-tie through as on the left. It didn't fit in as neatly on the right side, so I only made this change on the top. You might want to do it top and bottom, which is your call. Anyway, you can see that the nub won't seat into the cooler like they did on the left and sticks out a bit.
Photo #3 shows the finished setup, with only that one wire-tie nub showing on the right side. Photo #4 shows the switch on the dash, which isn't nearly as glaring in real life as it is in the photo. The switch (Radio Shack #275-712) illuminates when turned on. I've ordered a second HD accessory switch (71535-96) and will install it later, but this will be only a cosmetic change, as the RS switch works fine. Photo #5 shows the wiring schematic.
I'm hoping this will at least help with hot-weather traffic situations that cause the oil temperature to rise.

Wow. Nice job. Do you have an oil temp gauge that you can use to check how effective the fans are? Could you repost any info you have on the wiring please?
Last edited by iclick; Nov 13, 2008 at 01:44 PM.
Could you repost any info you have on the wiring please?
What's good about this is that the fans slip between the VR and cooler with about 1mm to spare. The bad news is that they stick up a bit above the cooler and I had to make a small shroud with some thin aluminum to keep the leakage around the cooler to a minimum. It's attached with double-stick tape, the kind used for auto trim molding, to the top of the cooler and draped over the fans. I'm thinking 70mm fans might fit better, not poking up above the cooler and maybe not requiring a shroud, but I couldn't find any 70x70x15mm Panflos. These fans seem to put out a fierce amount of air, even though they're rated at only about 35cfm each. You can feel the air flowing from the front of the cooler when they're on.
In rewiring for these fans I added more wire so that if the fans must be removed I'll have about 12" of wire to work with. When installed I fold up the wire and tie it to the frame near the VR.
I also revamped my dash arrangement, buying a second HD Acc switch in place of the gaudy Radio Shack switch I had, and also put in a black push-button switch on the far left, replacing the identical red one I had before. That one activates the garage-door opener and is a Radio Shack momentary switch.
The weather is heating up, almost 90° yesterday, so I'll be testing these fans sooner rather than later. Will report back when I have info on how this works in the real world. I did a 45-mile ride earlier and can report that the fans don't hamper cooling while moving. I thought perhaps they might slow the flow, but if so it doesn't affect oil temps. In this 85° weather they stayed between 185-200° for the whole trip. As for cooling when stationary I know they won't emulate a bike that's moving, but some air over the cooler must help, and will at least slow the ascent of oil temps when in a heavy-traffic situation.
Last edited by iclick; Nov 10, 2008 at 12:13 PM.
Trending Topics
The Best of Harley-Davidson for Lifelong Riders
Anyway, Quigley (see his note above) was selling some cooler-fan kits that included a thermal switch teed off the oil-pressure sender that could be adjusted to your temperature preference.



