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Hi, I'm Mike from 1A Auto. I hope this how-to video helps you out, and next time you need parts for your vehicle, think of 1AAuto.com. Thanks.
In this video, we're going to show you how to replace the serpentine belt tensioner. This is a 2007 Audi A4, which has the 2.0-liter turbo motor, and this procedure should be about the same for 2002 to 2008s with either the 1.8-liter turbo or the 2.0-liter turbo. Items you'll need include a new serpentine belt tensioner from 1AAuto.com, 18mm wrench, and a 13mm wrench.
The belt tensioner is right here at the front of the engine. Your 18mm wrench, put it right onto that big tab right there, pull on the tensioner, slip the belt off, and release the tensioner slowly.
The tensioner is held in by three 13mm bolts. You can remove the engine cover, just set it aside. Remove them with the 13mm wrench. I've removed two of them, just taking the third one out and lifting up the tensioner at the same time, and pull it up and out.
Here's the original part from the car and the new part from 1A Auto. You can see it's going to be an exact replacement, all the mounting points are the same, it does have this pin here, we're just going to push that out so it's flush, and then once it's installed we can move the tensioner, get the belt all set, pull that pin out and then it'll tension for us.
This pin right here is holding the tensioner itself in position, I'm just going to tap it, this is the side that's going to mount onto the engine, so I want this pin flush. Just use my 18mm wrench, tap it down so it doesn't interfere while I'm installing it, and then the lifting hook for your vehicle, put that in, and slide the tensioner down into place, and I have that bolt for the top already in. Put it in place and start threading that first bolt in, and as I'm putting them in, I notice that the belt has kind of worked its way up a little bit. I'll just push it down that way this is hanging nice and free, then I'll work the other two bolts in now.
Technical specs for these bolts is 30 ft-lbs of torque, I'm just using a regular wrench and getting them tight. You don't want to over tighten them because it is going into aluminum, and you don't want to strip the aluminum threads, but generally a good amount of force on just a regular wrench like this will work. The new tensioner has a lock in place holding it so you should be able to pull your belt up and put it on the alternator. Use an 18mm wrench to pull up, pull the pin out, and then slowly release and let the tensioner tension the belt. Then reinstall your top engine cover.
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