Short lived euphoria - vibrating fan noise from PFS SMIC?
 

Why couldn't this be a positive post about how I just pieced all these parts together on my FD and it runs ..... and runs excellent so far!?? PFS intercooler, efini y-pipe, FC thermoswitch, a few water and vacuum hoses, new plugs and wires, and leading ignition coil. A lot of work for a noob. I was afraid. 2 months later.....it paid off! No hesitation, boosting great (11-12 psi on a Pettit ECU is cool right?), sounds smooth, cooling better and earlier. And there's the rub. Like getting a Xmas gift and opening it up and finding a turd inside.

Since all these parts....my radiator fan is making a noise like it's hitting something....like a very resilient leaf when I first heard it (Autumn in VA.) I went underneath and found a small one protruding from the rad. Couldn't possibly be it but I hoped for the best and easiest. I also checked the fans by twirling it and didn't feel any type of resistance. Fans felt solid. The AST to Rad water hose was not in the way as I had to re-route it a bit for the new intercooler. It was good. Maybe it was that leaf?

Nope. Still making the noise. It's more a vibrating sound. I hear fan motors can fail etc but just wondering of any other possibilities before yet another project. Something simple please! Just call me a dummy and tell me it's something easy I'm missing. I just want a trouble-free FD! An oxymoron?

The only thing different than before is the PFS SMIC's weight on that fan. Can that bend the plastic fan housing and decrease the smoothness of the fans travel or something? I know most of it is on the metal bar, but it also leans on that fan. I know I'm reaching but the fan did not make the noise before this project. Mad coincidence of failed fan motor? I loosened the IC and tried lifting it while the fans ran and it didn't change the rhythm of the noise so I don't know about that theory. That IC didn't really budge though. It's not resonance because the blades are still 4 and 5. Maybe I'm hearing things? I can learn to ignore that frequency. So tiring the FD.....

I know I have to go back down there with any explanation....just ranting. As always, thanks!

its most likely hitting the smic duct, i have the same problem with my pettit duct, i just pull my duct up a lil and it stops, when the cars on and hood shut you cant really hear it..

The PFS duct doesn't fit well with aftermarket radiators. With the N-flow I used it didn't fit at all - at first.

To get a PFS duct in with a Koyo N-Flow and I had to lower the radiator and power steering loop about 1". I made spacers and used longer bolts to lower the assembly. I even had to notch the front bumper support a little to get the radiator to come down even further.

If you just have minor scraping - you might need to lower the radiator a bit.

My PFS fits fine with a Fluidyne. And I don't think the duct even touches the fan assembly. If it does, it's not significant.


Zoolander, if you haven't yet, use a flashlight and check the blades of the fans? I think they're pretty soft plastic and would probably show evidence of any contact....especially on the leading edges. And that would at least give you an idea of where to look.
Did you re-route the overflow hose at all? Maybe a bit of loose electrical tape, a wire just barely touching?

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I think I fixed it. I removed the battery today to get a better look at the driver's side fan. Upon spinning it carefully, I can discern a small amount of resistance. The tips of the blades are in fact black - again slight. It was definitely rubbing on the PFS duct as the duct has an indent to protrude through the fan housing a bit to help it fit snug...from what I can feel. I lifted it up and shimmied it between the duct and fan housing using a piece of silicone from an old coupler. It was a bit tough to get under there. I tested it by spinning the fan repeatedly and it seemed okay. On to the test drive.

Driving okay but temps start to rise. 220 on water and oil. 220 on my water was normal before the FC thermoswitch...but now I'm a bit worried. Turn on the heater to help cool the bay while cruising home. Pop the hood and.....the PS fan is running but not the DS fan! I reach down and that fan blade is completely STUCK! I can smell burning....like rubbing alcohol...metal. If I didn't have a burnt fan motor before it may seem I have one now! Remove the battery and play with the blades. It's actually stuck on the fan housing. I guess my original theory has some validity as somehow the blades circular path got tilted and hit against the side of the fan housing. Or maybe it was me from spinning it to test. It's wedged! I got a nice burn from the piping hot front center of the fan while feeling around. I wiggle and jiggle the blade and it finally pops free. Again I spin to make sure it's working...which it does freely again. Put battery back on and fire up the car.

Car warms up and fans start spinning - both of them! Vibration is still slightly there but I just played with the duct and it disappeared. I press down on the duct to make sure and yup...it's slightly hitting again. I play with it some more and now the noise is gone, even if I push down on the duct. Weird. And by "play"...I'm talking mere millimeters. All it takes.

I don't think this is the last of it though. If that duct moves during driving it may come back. Also, of greater concern is the fan blade hitting the side and stopping completely again. Random? I now have a new thing to worry about. Like your sign says 7dust......I hate FD's!

Long story short: PFS SMIC duct = culprit. Solution = create space between fan housing and duct.

Thanks everyone.