2008 Bmw 535xi Serpentine Belt Diagram

12:57 AM

So I am starting to questions my self and my sanity so that's why I am posting here to see if in fact I am crazy sorry for the typos I am sick and the nyquil is getting weird...

So I was checking out my car the other day and lucky me, the Serpentine Belt has a 6 inch scab in it. From the picture you can see that if the belt never stopped between the alternator and the tensioner I would have never seen the damage. (last pic)

I compared the belt routing on my car with the belt routing from RealOEM and an internet picture of the N54. To my surprise I found out that my belt is routed the same way RealOEM shows, but differently than then N54 picture. At this point I am thinking the cough medicine....maybe.

Further research shows that early E90's with N54 have issues with the P/S pump pulley. Someone please tell me that the dealer knows how to put a serpentine belt and that they didn't cause a recall out of negligence. Hopefully I am not crazy

If anyone has any guesses please shoot. I guess the next question would be: What does your serpentine belt look like?

Picture Explanation:

N54 Picture = N54 Picture
N54 Technical Drawing = RealOEM.com Drawing = My car

Let me know if i am the only one seeing the difference

03-31-2011, 08:17 PM

Quote:

Originally Posted by Jaza45

Mine is set up like the technical drawing, I just checked it...I think originally it was like the first picture, but they had problems hitting the sub-frame or so I've heard....

I was thinking the same thing, but it seems that if you set up the belt like the real picture that deflection pulley will hold the AC compressor and P/S pump towards the crank. My logic could be wrong tho....I am off to the garage and tomorrow I might visit the dealer and ask what they know.

04-01-2011, 11:23 PM

So this is what I got, the P/S pump pulley was broken on the back side. You can clearly see where the belt hit the subframe. I don't think the subframe needs to be replaced, but I want to hear your guy's opinion too. I am also not sure how to set up the belt once I get the new parts in, since my set up of the belt was the same as the diagram.

Otherwise the other pulleys look solid. If you notice I have some oil on the front of the engine so my oil filter housing gasket needs replacement which I will do with this repair.

I would suggest for everyone to check their belt, if you notice in my first picture of the scab near the tensioner, the belt lettering that says BMW is more worn out on the inside (towards the engine). I would say that is an indicator of uneven wear. Also sorry if some of the pics are upside down I tried rotating them but once uploaded they look however they want.

05-25-2011, 06:01 PM

Quote:

Originally Posted by scbutler51

I just got finished replacing the serpentine belt on my 07 335i, and this thread was a lifesaver. I was trying to put the belt on using the diagram I got from another source and the photo similar to what you posted. There was no way the belt was long enough to go on that way. After wrestling with it for over an hour, I searched the internet and found this page and your diagram. Ten minutes later....the belt was on and I was buttoning things back up again.

I didn't expect to find some answers with regard to my serpentine belt until I randomly came across this thread. I was pleased to see a simple diagram that is pretty much self-explanatory. I also got the belt on after reading this post. The diagram was very helpful, and indeed a lifesaver. Thanks for sharing mate!

06-22-2011, 05:01 PM

Quote:

Originally Posted by peter_tz89

I am glad that this post has helped people, the only thing I can recommend is to inspect the P/S pulley when changing the belt. Cheers

Yep I just noticed my belt with the inside part missing for about a foot. I took it to my local import shop (Guadalajara Mexico is a tuff place to play with dealers) .. seems they are aware of the problem.. told me first off that the power steering pulley would need to be replaced .. and if I wanted a perm fix it would be 8000 peso's and a week of down time. which they would take the sub out and correct the issue.. so I put it on my todo list.

06-23-2011, 09:59 AM

Quote:

Originally Posted by brazilfree

Yep I just noticed my belt with the inside part missing for about a foot. I took it to my local import shop (Guadalajara Mexico is a tuff place to play with dealers) .. seems they are aware of the problem.. told me first off that the power steering pulley would need to be replaced .. and if I wanted a perm fix it would be 8000 peso's and a week of down time. which they would take the sub out and correct the issue.. so I put it on my todo list.

The PS Pulley caused three other pulleys to be trashed. Part of the belt stuck these causing them to lock up and become trash. .

06-25-2011, 09:33 AM

Quote:

Originally Posted by peter_tz89

So this is what I got, the P/S pump pulley was broken on the back side. You can clearly see where the belt hit the subframe. I don't think the subframe needs to be replaced, but I want to hear your guy's opinion too. I am also not sure how to set up the belt once I get the new parts in, since my set up of the belt was the same as the diagram.

Otherwise the other pulleys look solid. If you notice I have some oil on the front of the engine so my oil filter housing gasket needs replacement which I will do with this repair.

I would suggest for everyone to check their belt, if you notice in my first picture of the scab near the tensioner, the belt lettering that says BMW is more worn out on the inside (towards the engine). I would say that is an indicator of uneven wear. Also sorry if some of the pics are upside down I tried rotating them but once uploaded they look however they want.

My subframe had the same black mark in about the same place.. I am going to see if it can be smoothed off as the welding there is thick ( as it has a whole in it anyway I suspect one can get away with it) .. we will keep a eye on it and if it develops a crack I will replace it.

I welcome any thoughts or suggestions critical or otherwise. It's all a process anyway.

07-12-2011, 11:34 PM

Quote:

Originally Posted by peter_tz89

So I am starting to questions my self and my sanity so that's why I am posting here to see if in fact I am crazy

I'm about ready to pull my hair out with this belt problem I've been having. I'm going to check the power steering pulley problem tomorrow even though I'm sure it isn't the culprit. My 335 has been shredding the inside 2 or 3 ribs on the belt and wrapping them around the alternator, then throws the rest of the belt off. I've replaced the tensioner assembly, both deflector pulleys, had the alternator checked, checked the power steering pulley twice, and replaced the crank pulley with an ECS lightweight. The only thing I see that has changed is the two pulleys on the tensioner are getting a sharp edge on the inside of them over time. Which leads me to my next point.

One thing intrigues me about every pic I've seen of N54 tensioners, and I'm surprised that someone hasn't caught it yet or at least google isn't able to find it anywhere. BMW engineers are really starting to lose it running a ribbed side of a belt on a smooth pulley. Common sense must not be something they have. I've seen the engine bays of probably 100 different models of vehicles and not one has ever had a mistake like this tensioner. I'm going to buy a ribbed pulley tomorrow to replace it and maybe that will cure the problems.

07-13-2011, 06:47 AM

Quote:

Originally Posted by bo.benson

I'm about ready to pull my hair out with this belt problem I've been having. I'm going to check the power steering pulley problem tomorrow even though I'm sure it isn't the culprit. My 335 has been shredding the inside 2 or 3 ribs on the belt and wrapping them around the alternator, then throws the rest of the belt off. I've replaced the tensioner assembly, both deflector pulleys, had the alternator checked, checked the power steering pulley twice, and replaced the crank pulley with an ECS lightweight. The only thing I see that has changed is the two pulleys on the tensioner are getting a sharp edge on the inside of them over time. Which leads me to my next point.

One thing intrigues me about every pic I've seen of N54 tensioners, and I'm surprised that someone hasn't caught it yet or at least google isn't able to find it anywhere. BMW engineers are really starting to lose it running a ribbed side of a belt on a smooth pulley. Common sense must not be something they have. I've seen the engine bays of probably 100 different models of vehicles and not one has ever had a mistake like this tensioner. I'm going to buy a ribbed pulley tomorrow to replace it and maybe that will cure the problems.

my money is on you finding that the back part of your PowerSteering Pulley has damage.. and when you fix it you will find a black mark on your subframe under the pulley location.... my others became trash when part of the belt locked them up and caused the damage to the pulleys Hope you find something else but my tech was very aware of the issue and knew just from looking at the belt what the problem was.

What part of Arkansas? I went to school at ALMA.

07-13-2011, 01:41 PM

Quote:

Originally Posted by brazilfree

What part of Arkansas? I went to school at ALMA.

I'm from Jonesboro, but I've been in the Alma area a few times at playoff games.

No damage. And couldn't see any rubbing on the cradle.

Did find that the tensioner that I had replaced back in August had been letting the upper pulley flex into the tensioner frame and burnt it down. Probably locked it up and slid the belt inward, I figure this is what has been happening all along. This time it just burnt it bad enough I could tell upon removal. So I replaced it with a ribbed pulley from the parts store and went back to the OE tensioner assembly. The OE didn't have any visual damage on the frame so it must be built slightly stronger inside or something.

07-13-2011, 10:27 PM

Quote:

Originally Posted by bo.benson

I'm from Jonesboro, but I've been in the Alma area a few times at playoff games.

No damage. And couldn't see any rubbing on the cradle.

Did find that the tensioner that I had replaced back in August had been letting the upper pulley flex into the tensioner frame and burnt it down. Probably locked it up and slid the belt inward, I figure this is what has been happening all along. This time it just burnt it bad enough I could tell upon removal. So I replaced it with a ribbed pulley from the parts store and went back to the OE tensioner assembly. The OE didn't have any visual damage on the frame so it must be built slightly stronger inside or something.

Glad to hear you don't have my issue.. it is a PITA .. I take it in Monday to try a correct this issue.