Home » A pulley for your thoughts (Subaru ac pulley replacement)

A pulley for your thoughts (Subaru ac pulley replacement)

The latest edition to the Driveanotherday HQ is a 1994 Australian delivered Subaru Impreza WRX, completely stock save for the nice boxer rumble from the dealer fitted Lucas exhaust. And while this low k, well kept example cruises very nicely on the open highway, it’s come with a high pitched whine very similar to a supercharger winding up…

Sadly though, there was no supercharger fiited (we checked) and the whine turned out to be from a common noise culprit in the EJ20 block, the air conditioner idler pulley. That’d be this part right here:

Subaru air conditioner idler pulley
Whines like a spoilt child

Sometimes the bearings in this pulley start to wear and get caked with dirt and other road grime and the once free spinning air conditioner idler pulley suddenly finds itself struggling to turn, which ultimately creates the unwanted noise as the ball bearings grind to a halt. Untreated, your air conditioner idler pulley could eventually seize up and throw a belt (or throw a belt into something worse or wreck its assembly) so it’s best to sort out a replacement if the noise is pretty evident (from inside the car and from pedestrians giving you weird looks).

Thankfully there’s a few options depending on your budget.

  1. You can purchase a new part from your local Subaru dealership. The part number we needed for the 94 Subaru Imprezza WRX was 73131FC000 (check to see if it’s the same part number you need for your Subaru). This will be your most expensive option and even more so if you organise dealer fitting instead of doing it yourself (we’ve seen tem go from $70 up to $100 locally.)
air conditioner idler pulley
OEM AC Pulley
  1. A visit to your local wreckers. Possibly your cheapest option depending on which wreckers you visit but your air conditioner idler pulley won’t last as long as a new unit and you might find yourself in the same boat as you started in.

  2. Use the air conditioner idler pulley alternative by Nuline. According to thier online catalog the part you’re looking for is EP136. You’ll have to fit it yourself unless you pass the job onto your local mechanic but we’ve attached a handy guide for DIY below. From a cursory glance on Google, the air conditioner idler pulley alternative from Nuline is quite a bit cheaper than the OEM and works just as well from Subaru owners with the same problem.

Air conditioner idler pulley
Nuline AC Pulley
  1. Australian Repco stores stock their own copy of the Nuline AC Pulley, the RPU636 priced at $40. Compared to the original factory pulley, the centre is slightly larger and without the original circlip, it’ll come flying off. But once clipped in with the belt tightened, it works just as well with little noise.


For ProjectWRX out the back we’re going with the 4th option as we still need to purchase CV Boots, rear brake pads and new wipers to ensure roadworthiness and with all the usual household bills turning up at once…

Since this seems to be a common problem, there’s a couple of handy guides on Youtube to help you switch them over:

Air conditioner idler pulley swap

Idler pulley removal and replacement


Just be careful with the tension rod mechanism that holds the pulley in place. While the earlier ones are made from metal, later Subaru’s came with bakelite/plastic versions that can break easily if you overtighten. If you do snap it though, your local Subaru dealership should have plenty spare.

Additionally don’t try to remove any circlips you find with anything less than a proper remover tool. You can hack away at them with pliers and a screwdriver to pry them loose but having done this ourselves we don’t reccomend this..


SUBARU OEM 73131FC000 Drive Belt Idler Pulley/Idler Pulley

4-in-1 Snap Ring Circlip E-Clip Retaining Ring Pliers Set – Soft Grip

300-Piece Snap Ring Shop Assortment – 18 Sizes

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