2010Merc801 Posted February 9, 2020 Share Posted February 9, 2020 A year ago my 2.5 started a new, louder, whining noise in addition to the cacophony noises that it normally makes. Trying to find that noise, I replaced the alternator, water pump, large idler pulley (no. 6 in diagram) and the belt tensioner. I didn't figure out the noise until the small idler pulley (no. 5 in the diagram) broke apart and tore up the belt. It took about 6 months, or 10-15k miles, of steady humming before it finally died. It was my fault for not finding the problem in the first place. I fixed that by drilling a hole in the fender well so I could get to the bolt on the pulley, and replacing the pulley with an Autozone Duralast part I found locally in stock. The OEM pulley, the pulley I removed, and the Duralast part I put on, both seemed like cheap pieces of plastic that would not last as long as the other metal idler pulley. It has now been a year since the idler pulley failed on the road, and I would like to avoid a repeat of the pulley failing and tearing up the belt. I have heard some noise on start up that could be similar to the noise I was hearing. If you have replaced the no. 5 pulley in the diagram with a part that you felt like was a quality part, would you mind posting the part number? This pulley isn't expensive, and I would like to get a part that would feel like could last 100k. Thanks! 0 Quote Link to comment Share on other sites More sharing options...
2010Merc801 Posted February 11, 2020 Author Share Posted February 11, 2020 With 36 views in a couple of days, this idler pulley doesn't seem to be a common failure. I have ordered an AC Delco part of Amazon to replace the AZ Duralast that I installed a year ago. I will keep the used part in the trunk, just in case. With over 160k miles and relatively few problems, this Milan has been an inexpensive, decent car to drive. It was out of service for 6 months in 2018 while it waited for an airbag replacement. Besides replacing the parts trying to find the idler pulley noise last year, I haven't had to do much. I have owned it since 30k miles. I have struts on the shelf in the garage, waiting to change out on a nice day. I'm sure that will make a difference with ride quality. The brakes are original, and I'm sure they are due for pads/rotors/fluid. I have replaced the passenger side axle (dealership), throttle body, valve cover gasket, battery, both headlights (driveway repairs), and tires. The throttle body and battery both made a difference in the transmission's sometimes erratic shifting. It gets right around 30 MPG with mostly highway driving. The Camry I drove as an airbag loaner was a nicer car, and got 40 MPG, pencil and paper figured. With gas hovering down to $2.00 a gallon, the Mercury is less expensive to drive (factoring in the tiny amount of annual depreciation for my Mercury) , and easier to get in and out of. When my Merc had 80k miles I read a bunch of stuff about EPAS failures and transmission failures. I thought about getting rid of it, but I'm glad I didn't. I hope yours works out as well as mine has. 0 Quote Link to comment Share on other sites More sharing options...
HappyNem Posted June 13, 2023 Share Posted June 13, 2023 A part number you used would have been great. I'm having this same issue. Also, when I took this part off it was dark and everything dropped. I think I got everything, but now when I tighten the bolt it locks up the pulley. I'm so lost and this is not a common part to replaces so its kicking my ass. Sorry for Necrorezzing this thread 0 Quote Link to comment Share on other sites More sharing options...
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