It means that the bearings aren't bad (making the sand grainy sound), but that the lubrication is not would it should be (spinning freeing), and it's only a matter of time, perhaps short, before the bearings will be shot.

I was in the same boat with mine, at 80K mls, and decided to replace them both with the belt. The chances are I won't have this car at 160K, when they'll need to be replaced again, so why risk them breaking the belt and leaving me stranded, and possible damage to my A/C compressor, which is on a lot in Phoenix (so more risk.)

I had the same issue with a crooked tensioner and decided it was best to play it safe and change it out for all the reason quoted. It's a pretty simple job, even coming from someone with limited skills like myself. The last thing you want is that belt coming off while you are driving.

i bought both the tensioner and idler pulley including shipping for only $93 after shopping online for a bit. www.oembimmerparts.com

I'm gonna be replacing my belt sometime this week. Any pointers/tips for a 1st timer?

Thanks

Thank you for your DIY. It took me only 20 minutes to replace the tensioner, the idler pulley and the serpentine belt. I took a 16 inches ratchet with a T60 to unload the tensioner in front of the car and it wasn't hard at all with that. I know, I'm very strong for my 160lbs... The idler pulley have a 16mm bolt and the tensioner's bolt took me a E14 torx box.

Good to hear you got it done. Glad i could be of help.

Straight from TIS, those numbers mean a specific section of the Torque Specification Document.

This is ONLY for N52 engine, the 335i N54/N55 might be different.

Torque to 18 ft pounds for the tensioner, THEN torque it 90 degrees ignoring the torque. This is known as Torque to Yield or Torque to Angle, and I believe streches the bolt and allows for more consistency then if they just gave you a flat torque number.

No where in TIS did I find the specs for the idler pulley, but the idler pulley on the alernator is 40nm or about 30ft lbs so I'm going with that.

So I replaced the idler pulley, tensioner, and belt about a year ago (03/11/12) using this DIY as the belt was riding about a 1/4 inch off of the tensioner. After replacing everything I checked the belt a few times a week for the first month to ensure that everything was still seated properly and looked good. Fast forward to tonight and while looking under the hood to see if I could figure out where a squeaking was coming from, I noticed that the belt had once again begun to ride off the tensioner about a 1/4 inch.

Has anyone else seen this happen again after changing out the idler pulley, tensioner, and belt? It's a relatively simple job if I have to do it again, but I'm a little aggravated that this would happen again in such a short period of time and especially considering I have to buy all of the parts again!

all parts are available from autohausaz for $112

so whats everyone's mileage when they change the belt and pulleys???

I replaced my idler pulley, tensioner, and belt on my 07 at 64,227 miles.