Accessory Pulley/Tensioner Lifespan

[iamtrashman]

Edit

Found a thread on google after coming up short on the forum search.

here for anyone searching

[RocketyMan]

Originally Posted by iamtrashman

Hey Everyone,

I am currently fixing an OFHG leak and have the fan removed and all of the stuff off the front of the engine. I was planning on doing belts while I have everything apart, but I was curious what everyone's opinion on the service life of the idler pulleys and tensioners should be?

My car is a 2009 with right around 100k miles. I usually like to replace things "while I am in there", but I have already ordered what I need for the job. After disassembling it I realized it was an easy stage to replace the pulleys/tensioners, however it is about 1000$ CAD to replace these parts by the time shipping and duty is accounted for.

I have no BMW dealer in my town and the closest is 2 hours away, and they are usually much more expensive than online. There are no Canadian online OEM parts retailers that I know of, so international shipping and duty is unavoidable.

I have inspected them pretty closely, none of the pulleys spin too freely or show any signs of damage, essentially zero play side to side, and the hydraulic tensioners show no signs of damage or leaking.

What would M3P do? As I said, I am a proponent for "while youre in there" jobs, but I also don't like to replace things that seem totally fine for no reason.

Thanks

Take apart the pulley and spin it. You should be able to tell if there is an excessive amount of play in the bearing, does it feel gritty, is it noisy, and then be able to make a decision. From what you described as checking yourself they sound good. There needs to be a little bit of drag from the grease encapsulated in the bearing. Sometimes the grease dries out and you can get away with simply cleaning out the races and repacking with fresh grease.

If you search the forum, you can order just the pulleys you need that are not expensive.

[iamtrashman]

Yep I ended up finding that thread afterwards and did just that. One thing I didnt take into account is the wear of the actual plastic pulleys themselves. I didnt realize they are smooth when new, and mine have some grooving. I think the bearings are fine but the wheels are probably on their way to failing.

Thanks!

[RocketyMan]

Yup. That grooving is most likely just typical from the reverse PS pump needing the double-serpentine belt.