If you have this sound, it means your serpentine belt is slipping, most likely b/c of your alternator pulley. Here's how to tell. Turn off your air conditioning and back up. The chirp/squeal/squeak sound should be reduced or gone. If this is the case, there is a bearing (sprag) inside this pulley that went bad and can essentially take out your A/C compressor, costing you A LOT. I saved myself this fate, and you can too. Here's how...

1st- Decide if you want to replace just the alternator pulley or the whole alternator (rebuilt one from auto zone is $180). I was NOT comfortable with removing the alternator, so I opted to just replace the alternator pulley b/c it CAN be done without taking out the alternator. BUT you need the right tools. I take my tools back, judge if you will, so for me, it only cost $55 (alternator pulley cost from pelican parts) when the smoke cleared. If you opt to take out the alternator pulley, I can help.

DIY Alternator Pulley replacement

Steps: 1) Loosen serpentine belt (it's the only belt) 2) slip the belt off the alternator pulley 3) take off old pulley 4) install new pulley.

This is harder than it sounds.

Step 1: you need a T-60 and apply to the image where it's circled in red.
The trick is when you turn it counterclockwise! you only turn it half a notch and the belt will loosen. You have to keep holding it in this position and then with your other hand, slip the belt off the alternator pulley. This is a pain b/c you have to first remove or loosen a bunch of stuff including, removing the air filter & intake (pretty easy), then loosening the wideband silencer (don't have to remove it completely, just enough to slide it and make room to get the T-60 in. To do this, follow Leer73's advice: "There are large hoses that go into both ends of the silencer. Pop the clips up on each hose so you can remove them, then remove the smaller hose attached to the top of the silencer with a flathead screw driver and swing that hose out of the way. Remove the 2 bolts that are holding the silencer in place. Now you don't need to pull the silencer out at all, just remove the hoses , unbolt it and let it drop towards the bottom. It will be out of the way." Lastly, removing the top part of the coolant/radiator hose (have a cloth ready to plug up the coolant that will leak out from the top of where you removed the hose. Once you pop the top part out, move it to the side.

Step 3: To take off the pulley, watch this video starting at 3:28. You will need these "Gates" tools as well. I got a used set off amazon for $50. Watch this video a few times. Here's what they don't tell you... 1) Which way to turn the wrenches and 2) It takes A LOT of force!
First, spray some penetrating oil (like WD40) into the alternator pulley hole and let it soak in for at least an hour.

NOW, you see the two wrenches he uses? You need 'em both, the open-end box wrench (the one closest to the alternator pulley) holds the inner spline piece in place while the 1/2" ratchet (get a LONG one, breaker bar style) which is attached to the piece that connects into the alternator shaft is twisted CLOCKWISE! Here's why. The pulley comes off counter clockwise, like normal. BUT to get it to screw off, you need to turn the alternator shaft clockwise which will cause the inner box wrench to essentially be turning the pulley counter clockwise. (Re-read this b/c this is the super important point that NO ONE helped me with, not pelican parts, not this forum, not any forum. I basically went with my gut that there was no nut at the end of the alternator pulley)

NOW, have a friend hold the inner box wrench while you try your best to twist the 1/2" ratchet clockwise. OR, with a good sneaker/shoe on, put your foot against the inner wrench to hold it (the inner spline) in place while you twist the outer 1/2" wrench your hardest clockwise till you either strip the alternator shaft or get it loose. Hopefully the latter or you'll be needing the replace the whole alternator. (Yeah, so don't be fooled by the video showing a kid who hasn't hit puberty effortlessly loosening the pulley from the shaft.

Step 4: Put new alt. pulley on in reverse to how you got it off. This is easy!

Everything is the reverse of how you got it off. The wideband silencer is a pain to get back on. The rest is easy. Afterwards, I let the car sit for an hour, then turned it on with the air conditioning OFF, let it run for a minute or so, reversed it, drove around w/ no a/c on. Then the next morning, turned on a/c, turned on car, reversed. No squeel, no squeakingl! Note, it took a while to find that nut to put the T-60 in, so once I did, I left it in while I did everything else so when I was done and onto slipping the belt back on the new alt. pulley, I didn't have to find where the T-60 goes again. Cool? Cool. And thx. to VVF for helping to answer q's I had while doing this.

 

Couple notes - you don't need to take the coolant hose off, there should be plenty of room to remove the belt etc - done that last weekend when I replaced my belt and idler/tensioner pulleys.
The wideband silencer is super easy, probably it was your first time putting it back. It actually takes me longer to remove the fresh air hose on the front, close to the radiator, without the tool...

You basically can see the upper bolt hole for the silencer, so you align the upper bolt and start it. Then the lower bolt is no problem. You just need a good extension, I used a 4'' wobble extension.

Did the noise cease after the ordeal?

Your next project might be replacing the $50 voltage regulator

 

yup.
nope.

 

guys send me in whatsapp to add u to biggest MB group

00971506740840

 

Thanks allot for the DIY, did this last night using the above, thanks allot.

my bad for quoting...

 

Zim, please don't quote an entire message, especially if you are not specifically replying to some points

 

The second video does not work. it is private. could you please make the video as public.

Thanks

 

how i can c the 2nd video ??

 

 

Thanks to the OP for posting this. Just changed this out. What an exercise.

For the M271 1.8L, this job can be easy and difficult (in different ways) at the same time. Doing the job without removing the alternator means less room, but saved time. Removing the alternator (easily 1-2h more work) means one can use an impact driver for easily removal of the pulley. Both methods have their drawbacks. I personally did the job without removing the alternator. Also, by using an extension to twist the tensioner, I did not need to touch that coolant hose at all. One less mess to clean up.

Here are the tools required for the job:

7mm hex (for removing hose clamps)
E10 external Torx - for removing wideband silencer
Large slot screwdriver - for unclipping "lower" end of wideband silencer
T60 Torx - for unloading belt tensioner
Alternator tool - consists of 2 parts: a) 33 tooth spline tool for gripping the alternator pulley, and b) a long T50 driver for gripping the alternator shaft. Not sure if the Bosch alternators use anything different, but my Valeo used the T50. Both parts are needed, so do not procure only the spline tool.
Penetrating oil - use the best stuff you have. Do not skimp. If you do, I can guarantee that you will be hating yourself for hours, if not days.
Breaker bar for T50 bit - 18" or longer highly recommended
Wrench for spline bit (should be 17mm) - highly recommend box end type. The longer the handle, the better. Also find a 2nd wrench (or a suitable piece of pipe) for "doubling up". You will need this.
Various extensions (regular, wobble), ratchets
Hammer (I whacked the old pulley multiple times, not sure if it was effective in breaking it loose)

There are 2 different pulleys available, depending on the version of alternator involved. Be sure to get the correct PN by checking with the dealer. These pulleys have different dimensions and are not interchangeable.

As of the time of writing, the replacement pulley for my engine is A271-155-01-15. This is also known as an INA F-232001.09 pulley. Same thing, different box. The dealer wanted $256 CAD for the pulley, while I found it online (exact same OEM part) for $40 USD.

The alternator tool I purchased from Amazon is a CTA Tools 1072 (described as "T50 x 33 Spline"). This tool comes with the spline bit already set inside the T50 bit (the spline bit can spin and slide freely but won't slide out the end of the T50). While this is great for preventing one from losing the spline bit, the problem with this setup is that it also forces one to use an open end wrench. My solution was to grind off the "ridge" on the T50 that prevents the spline bit from sliding out. Once the spline bit was out, I could easily slide a closed-end wrench (6 points of contact compared to the 2 for an open-end wrench) into the works. I would highly recommend this step, as my first few attempts (open-end wrench) ended up partially rounding the spline bit.

The OP does a pretty decent job explaining how to get to the pulley. Removing the wideband silencer is a bit tricky (especially if one drops the fasteners into the abyss below). Work slowly and carefully.

Drench that pulley in penetrant where the threads touch. Wait a while, then drench some more. Then add some more on top. And did I forget to say to add penetrant?

The amount of torque required to break the old (rusty and seized) pulley loose was nuts. My buddy pulled so hard he twisted (warped) the T50 bit, and partially broke a couple of teeth in the alternator shaft. I would guess the torque exerted would be in the 120-150Nm range. This was the part that took me several days, and I honestly thought I was going to strip or snap off the alternator shaft. This was a Hail Mary (or whatever deity of your choice) move. The OP suggests using one's foot. That is actually quite a valid suggestion. Yes, pull as HARD as you can, as if your life depended on it.

As mentioned by the OP as well, the pulley is removed when a) the spline bit is turned counter-clockwise (while the T50 is held stationary), and/or b) the T50 bit is turned clockwise (while the spline bit is held stationary). Basically one has to be turned against the other. Be sure to understand how this works!

According to the WIS, the new pulley should be tightened to 80Nm, or 59ftlbs.

Lastly, to potentially prevent some serious frustration, I would recommended first attempting to break the pulley "loose" from the alternator shaft WITHOUT touching the serpentine belt or wideband silencer. The goal is simply to break the rust bond between the pulley and alternator shaft. The reason for this is because if pulley remains completely seized to the shaft, everything else is a waste of time. No point spending 1h removing everything only to find out you're stuck. To get quick access here, simply remove the engine intake pipe, "unclip" the lower wideband silencer hose, and move it out of the way (I lifted it up and wedged it against the radiator fan). Nice quick access to the pulley in under 2 minutes if you know what you're doing.

Here's a video (not mine) explaining the alternator pulley replacement procedure: