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      10-06-2016, 09:02 AM   #155
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Quote:
Originally Posted by DIABLOW View Post
Something missing here, no belt diagram.
Best thing, if your belt didn't blow up, is to draw your own diagram before you remove the belt. Even if the belt blew up you can see from the wear on the pulleys how the belt would have been routed. But the easiest approach would be to follow this diy:

http://www.e90post.com/forums/showthread.php?t=1075854
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      10-29-2016, 10:34 AM   #156
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Heard belt slip noise, looked at the belt and it was nearly half off the pulley on the tensioner arm. Am set to replace and just now noticed the bolt head on the tensioner sheared off as well. And I think it's actually been sheared off for a while since it's aged looking on the newly exposed portions. You guys might want to look at the bolt on your tensioner arm. Luckily I heard belt noise to warn me instead of the thing just coming apart.

Hopefully I can just get the tensioner arm off and vise grip the rest of the bolt out without drilling. Really limited on tools I have access to right now lol.

Lol, the tensioner arm would not come out with the broken bolt in there and the damn thing was almost flush, so I couldn't really grab it very well, but it spun right off by hand. 25nm is @18.5 ft lbs. Not sure how much the extra 90 degrees add, but I guess it's still a low torque and most likely that bolt came loose and was backing off a tiny bit, then probably bent a tiny bit or was put at an angle and then the head eventually sheared off. Gonna put a little bit of low strength locktite (purple) on the new bolt. Betting if the bolt doesn't go loose, the head would have not sheared off.

Last edited by Casca; 10-29-2016 at 12:11 PM..
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      01-11-2017, 10:44 AM   #157
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Just had an oil leak coming from the oil filter cap after I replaced the gaskets and filter I now have a constant squeezing noise. Pretty sure oil got on the pulley on the alternator as when I rub it it's the only one that is dirty wii black grime. Tried spraying grease lighting on all the pulleys and belt and washed with water but no luck. Crossing my fingers if just getting a new belt and scrubbing the pulleys before installing the new one will cure my issue.
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      08-19-2017, 11:35 AM   #158
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Glad I came across this DIY and post, I have 100,000 miles

I'm really happy I found this post, or I would have been in trouble at some point. I was reading this post, then thought I better go check my car because I don't ever recall checking it or hearing about this. Sure enough, I see the belt is a quarter of the way off the tensioner. I ordered from the link above from FCP Euro, it arrives, and it's a perfect fit. The wheels and pulleys were definitely shot and sound just like in the video in this post. Replaced it in about an hour following the instructions with no problems. Appreciate this forum every day it seems like.
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      08-19-2017, 12:32 PM   #159
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Quote:
Originally Posted by Austin LeNomad View Post
I'm really happy I found this post, or I would have been in trouble at some point. I was reading this post, then thought I better go check my car because I don't ever recall checking it or hearing about this. Sure enough, I see the belt is a quarter of the way off the tensioner. I ordered from the link above from FCP Euro, it arrives, and it's a perfect fit. The wheels and pulleys were definitely shot and sound just like in the video in this post. Replaced it in about an hour following the instructions with no problems. Appreciate this forum every day it seems like.
Great! welcome to the forum btw
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      08-25-2017, 04:45 PM   #160
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Thanks for the DIY. I just replaced the accessory belt, tensioner and idler pulley on my 2009 E90 328i with 70k miles. Turns out the previous owner had already replaced the belt and tensioner as the tensioner bolt was not blue and the tensioner and belt had 2015 dates. I went ahead anyway since the idler pulley was original. I bought the Contitech ADK0022P kit which included:

1. Contitech belt (made in Germany)
2. INA tensioner, bolt, cap (made in Germany)
3. INA idler pulley, bolt, dust cap (made in France)

These parts are the same as OE as far as I can tell. Shop around for the cheapest price; I ended up buying from Rock Auto.

Unloading the tensioner was easy with a T60 socket and a 15" breaker bar. The idler pulley previously installed had the bolt retaining clip, but I removed it on the new pulley as per Continental's instructions. I torqued the tensioner bolt to 20 ft-lbs + 90 degrees and the idler bolt to 35 ft-lbs.

Here's a belt diagram for reference:



Update: the bearing on the tensioner started crunching/rattling after 14k miles:



I was only able to diagnose the noise with a mechanic's stethoscope where I could hear the bearings crunching in sync with the rattling sound. Upon closer inspection, the INA tensioner I installed had no country of origin marks while my old INA tensioner said Germany on it. According to FCP, the new tensioner is made in Slovakia: https://www.fcpeuro.com/products/bmw...em-11287530314

It seems that INA moved production to Slovakia as the "BMW" tensioner is also made there: https://www.fcpeuro.com/products/bmw...ly-11288624196

I refitted the old German INA tensioner with a new aluminum bolt and the rattling disappeared. For whatever it's worth, the German tensioner was marked "04.02.15 J.5" while the Slovakian tensioner was marked "07.12.2016 K.5"

Last edited by The Nightman; 05-27-2021 at 12:37 PM..
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      08-31-2017, 05:04 PM   #161
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Bentley has revised their torque spec for the idler pulley:

https://wiki.bentleypublishers.com/d...que+correction

Now 40 Nm (30 ft-lb)!
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      12-13-2017, 10:25 PM   #162
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I have read that the tensioner bolt is one time use.
Is this true?
I ask because I recently had my tensioner pulley replaced at a garage and it wasn't clear if they replaced the bolt or re-used my old one.
It looks like the same old one (old aluminum looking with the blue paint dot)
Is that how the bolt looks when new?
2007 328i
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      12-14-2017, 12:05 PM   #163
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Quote:
Originally Posted by 613328i View Post
I have read that the tensioner bolt is one time use.
Is this true?
I ask because I recently had my tensioner pulley replaced at a garage and it wasn't clear if they replaced the bolt or re-used my old one.
It looks like the same old one (old aluminum looking with the blue paint dot)
Is that how the bolt looks when new?
2007 328i
Not 100% sure but I believe blue painted bolts are from the factory. The blue paint indicates aluminum and one-time use. None of the replacement bolts I've ever bought have paint on them. You might want to ask your shop if they replaced that bolt. It would be disastrous if it snaps.
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      02-22-2018, 09:48 PM   #164
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I need clarification. Got the idler pulley from fcpeuro. The box has a pulley with bolt and a dust cap. The pulley has a metal washer in the rear.

Do I need to remove that washer or install with that ?
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      03-25-2018, 08:38 PM   #165
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reflection pulley

Quote:
Originally Posted by buytamil View Post
I need clarification. Got the idler pulley from fcpeuro. The box has a pulley with bolt and a dust cap. The pulley has a metal washer in the rear.

Do I need to remove that washer or install with that ?
Hopefully not too late for your question.

You need to keep that metal disc retainer. When you remove the old one, you will also see the same metal disck retainer there.
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      03-25-2018, 08:48 PM   #166
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Some very helpful tips for people:


WARNNG1:
Something most of the Online DIY missed was the use of Torx T60 instead of T55!
I was unlucky and perhaps my tensioner had too much dirt built-up. I stripped the Trox hole with T55 and it was a terrible and scary feeling.
I ended up finding a T60 to finish the job properly.

Warning 2:
Many people got stuck after the new tensioner is installed and are trying to pull the belt on the tensioner wheel. It seems that the belt is just missing a few cm and can never be put on the tensioner.

When you encounter this problem, do not panic. Do not try to torque the torx hole with T55 to see if you can release more tension. You will strip it as well! The proper way to find slack (there must have) from the belt routing. A proper installed new tensioner will not need any extra effort to have the belt slide on it. Remember!
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      03-26-2018, 04:52 PM   #167
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similar situation

Quote:
Originally Posted by Spy021 View Post
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!

Hi,

Too bad no one replied your message. I have a similar situation except that my case is more mild. On the old tensioner, my belt is flush against the tensioner wheel edge. No vibration and no z-axis movement (in-out movement) When I put the new kits on, I push the new belt in 2-3mm on the new tensioner, but after the work is completed and letting the car do a test run for 20min, the belt is again flush with the tensioner wheel edge. So strange, as if that suppose to be the correct position for the belt.

Did you eventually figure out what is your issue?
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      05-21-2018, 01:12 PM   #168
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Quote:
Originally Posted by orion_squall View Post
Hi,

Too bad no one replied your message. I have a similar situation except that my case is more mild. On the old tensioner, my belt is flush against the tensioner wheel edge. No vibration and no z-axis movement (in-out movement) When I put the new kits on, I push the new belt in 2-3mm on the new tensioner, but after the work is completed and letting the car do a test run for 20min, the belt is again flush with the tensioner wheel edge. So strange, as if that suppose to be the correct position for the belt.

Did you eventually figure out what is your issue?
I just had it replaced on '06 n52 with parts from fcpeuro and the belt is flush with the tensioner pulley. With the old tensioner the belt was about 2-3mm inwards on the pulley.

Seems like this is normal on the new tensioner since everybody else is reporting the same thing.
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      06-12-2018, 05:11 PM   #169
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Quote:
Originally Posted by ukr View Post
I just had it replaced on '06 n52 with parts from fcpeuro and the belt is flush with the tensioner pulley. With the old tensioner the belt was about 2-3mm inwards on the pulley.

Seems like this is normal on the new tensioner since everybody else is reporting the same thing.
After reading about possible damage from bad pulleys, I inspected my engine and found that the belt is just hanging over the edge of the tensioner pulley by about 1mm and not flush. The pulley isn't wobbling, however it almost looks like it's not on the same plane as the other pulleys. Is it time to replace it? Can I get away with just replacing the pulley and not the entire tensioner? The belt looks good with no cracks and there's no squeaking or other noise.

Last edited by lowrydr310; 06-12-2018 at 05:21 PM..
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      06-28-2018, 02:30 PM   #170
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DIY Replacing N52 tensioner idler pulley and serpentine belt

That makes sense and I completely agree.

Whats your thoughts that I never heard the relay for the primary pump?
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      06-28-2018, 04:40 PM   #171
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Quote:
Originally Posted by lowrydr310 View Post
Quote:
Originally Posted by ukr View Post
I just had it replaced on '06 n52 with parts from fcpeuro and the belt is flush with the tensioner pulley. With the old tensioner the belt was about 2-3mm inwards on the pulley.

Seems like this is normal on the new tensioner since everybody else is reporting the same thing.
After reading about possible damage from bad pulleys, I inspected my engine and found that the belt is just hanging over the edge of the tensioner pulley by about 1mm and not flush. The pulley isn't wobbling, however it almost looks like it's not on the same plane as the other pulleys. Is it time to replace it? Can I get away with just replacing the pulley and not the entire tensioner? The belt looks good with no cracks and there's no squeaking or other noise.
From what I've gathered about the tensioner is that the bolt can bend(weak aluminum)or even the tensioner,causing it to fall away from engine all while mis-aligning the belt until it falls off and possibly causing all sorts of peripheral damage that far exceeds the cost of tensioner.
Also bearings get worn introducing unwanted tilting of pulley.
So if it's hanging you would be best to just change it and be done with.
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      07-02-2018, 04:54 PM   #172
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Quote:
Originally Posted by Needbmwpartzz View Post
So if it's hanging you would be best to just change it and be done with.
I realized that after reading a bit more, and also upon further inspection of mine I noticed some slight z axis wobbling. When I saw pictures of what could happen to the N52 with a broken belt, I quickly ordered a new tensioner.
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      07-20-2018, 02:17 PM   #173
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Quote:
Originally Posted by buytamil View Post
I need clarification. Got the idler pulley from fcpeuro. The box has a pulley with bolt and a dust cap. The pulley has a metal washer in the rear.

Do I need to remove that washer or install with that ?
Instructions in the Conti box say to remove the silver plate. It is merely a holder for the new bolt in the box.
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      07-21-2018, 05:41 PM   #174
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tips after doing this job

Just completed this job using the Conti kit.

A few thoughts:

You will need a torque wrench that reads at the 25 Ft Lb level to set the tensioner bolt, after which you should turn it 90 degrees more.

My 1/2 drive torque wrench started at 35 lbs, because I could not use my 3/8 drive wrench with an adapter due to lack of clearance. I had to estimate it. You also cannot get a 90 degree rotation in one movement, either.
Torque angle gauges are under 10 bucks at Amazon, if you plan in advance like I did not.

The pin in the tensioner did not allow sufficient slack to fully wrap the belt, so I found it easier to remove the pin, use the torx tool and breaker bar to release the tension and wrap the final pulley around the power steering pump down low (after removing the air cleaner box).

Lastly, there was insufficient clearance to allow me to R & R the belt off the crank pulley, but by pushing down on the metal line in front of the pulley with a stick, clearance opened up.

Damn, this reminds me too much of working in my 1960 Mini's engine compartment....

Bet I could do the job in 20 minutes as someone else posted in a forum, but will not need this new-found skill for another 4 years.
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      07-26-2018, 02:33 PM   #175
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I just did mine...the pin left perfect slack just make sure the belt is around all pulleys correct and tight u will have plenty of belt if belt is not seated in groves and around properly will not have enough belt...make sure don't have any slack in belt u be fine..
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      04-19-2019, 11:00 PM   #176
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Quote:
Originally Posted by orion_squall View Post
Hopefully not too late for your question.

You need to keep that metal disc retainer. When you remove the old one, you will also see the same metal disck retainer there.
Can someone please confirm about keeping the retainer? One comment from pelican parts stated to remove.

Thanks!

Edit
Never mind! Despite instructions stating to remove, I compared the old and new and just installed with the retainer (like many others here). It’s really thin and goes into a concave area so if anything it’ll just be pushed out a little more. I received an email confirmation after install from FCP Euro that it’s not necessary to remove 😀.
Took an hour with cleaning and taking pictures.

In case anyone is wondering in the future, BMW told me this was a couple mm off and should be changed. I kept my eye on it and changed it 1 year, 8,000 miles later with no issue. No noise present. No bent in bolt. Belt had some cracking. Original lasted 120K.

Thanks to OP and everyone who contributed!

Last edited by profenx; 04-23-2019 at 12:17 AM..
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