BMW E90 320d belt removal

Dony · 21-06-2011 02:33PM #1

Hi there,
My wife's E90 is making a fairly screechy noise from under the bonnet.
After some investigation I've it narrowed down to a worn out tensioner pulley on the v-belt.
I bought a new belt and pulley so now I want to stick it on.

My problem is slackening off a smaller belt which needs to come off first in order to get at the main drive belt.
I think this smaller belt just runs a A/C compressor off the crank but I can't see one of those sliding adjusters that you used to see on the older alternators etc. Any ideas?
Do I need to take off the plastic tray beneath the sump?

I did a bit of trawling through some BMW forums but can't find anything.

Owen · 21-06-2011 05:19PM

If it's the same setup as my old 75, one of the smaller pulleys on the serpentine setup is a tensioner has a nut attached to it. A 24 spanner on that will pull it back and allow you to slip the belt on, and then it'll automatically retension.

Pulling it back is hard. Really fscking hard, the official tool has a long ass handle for it. I slipped with mine when it was under load and took a slice of skin off about 2 inches long and 5mm wide, and I remember looking at it thinking 'Oh yeah, any minute now, this is really gonna hurt'

[EDIT] I remember now that the airon belt had three pulleys, the main crankshaft pulley, the compressor itself, and a teflon pulley. That pulley was adjustable with a 10 socket.

Dony · 23-06-2011 12:06AM

Thanks for taking the time to write that but it sounds like that set up is totally different to the E90.
Besides, its the other smaller belt infront of the main serpentine that I'm having the trouble in slackening off.
Does anyone have one of these that knows what I'm on about?

Wheelnut · 23-06-2011 01:00AM

I have an E90 320d, 2009 and it has only one serpentine belt (It has electric power steering) What year is your's?

Paintdoctor is right about the main belt, there's an idler pulley (often there's a plastic cover on the nut) and when you turn the nut clockwise (tighten) it releases the tension on the belt and you just slip it off.

you might also research the diagrams on www.realoem.com

Owen · 23-06-2011 08:58AM

Dony wrote: »

Thanks for taking the time to write that but it sounds like that set up is totally different to the E90.
Besides, its the other smaller belt infront of the main serpentine that I'm having the trouble in slackening off.
Does anyone have one of these that knows what I'm on about?

I'd doubt it's a separate setup - it's been the same engine since the late 90's. Here's a diagram of the main Serpentine belt on your 320d from realoem.com http://realoem.com/bmw/showparts.do?model=VG92&mospid=50492&btnr=11_4153&hg=11&fg=18 item number 2 on that is the tensioner I'm talking about.

Here's the TIS bulletin on how to replace the aircon belt, which is exactly as I put it before :
http://tis.spaghetticoder.org/s/view.pl?1/04/53/52

Wheelnut · 23-06-2011 07:42PM

@Paintdoctor: I can only talk about my own 2009 car because Dony has not come back to say what year his car is. My car has the N47 engine (not M47) and I'm not sure of the exact difference. The photo shown in the TIS does not match mine because there are no ancillaries to the left of the crankshaft as viewed in the picture. The alternater, A/C pump and pulleys are all located to the right (passenger side). There is no power steering pump because it is electrical. I think this is the correct RealOEM diagram (at least for my car) and it can be seen that the tensioner pulley is near the centre of the cluster.
http://realoem.com/bmw/showparts.do?model=VG92&mospid=50492&btnr=11_4155&hg=11&fg=18

Owen · 23-06-2011 08:09PM

You may well be right, and I'm wrong. Found this post on e90post.com :

I got this done a little while back by an indie and I watched him do it. No pics taken but i'll put this in laymen terms. On the diagram above you can see where the tensioner pulley is. Well on the side of it is a place where you can put a T60 torx in it and using a socket wrench you pull clockwise to relieve pressure from the belt. before he took it off the mechanic drew a diagram of the belt and then he just slipped the new one back on the way that the old one went. It only took 5 min and he charged me 10 bux. So it was a quick and cheap fix ($35 to be exact!)

So that's for the Serpentine, but makes no mention of the aircon secondary belt. It's the secondary belt setup which leads me to think his might be the same as mine.

El Guapo! · 23-06-2011 09:32PM

If I remember correctly the air-con belt has a smaller pulley in between the air-con pulley and the crank pulley. This small pulley will have a plastic cover on the front of it that you can pop off with a flat-head screwdriver.
Once its popped off you should see a hole for a torx bit (maybe T35? I can't remember off hand). Turn the torx bit it this hole to move the pulley and release the tension enough to remove the belt.

Edit: I just looked at your diagram. If you look at number 3, that's th plastic cap you pull off to adjust the tensioner.

Dony · 24-06-2011 03:12PM

Yeah apologies for not getting back a bit sooner and thanks for the help so far.
The car is a 2005. I think there's about 85k on the clock.
That secondary belt doesn't seem to have a tensioner pulley.

Anyway, have a look at the picture.

El Guapo! · 24-06-2011 04:58PM

Its a stretch belt.
Ideally you need a special tool to get it on and off. I've gotten them on by hand before but believe me its a bastard.

You need something like this http://cgi.ebay.ie/STRETCH-DRIVE-BELT-INSTALLATION-TOOL-LASER-TOOLS-/350414047139?pt=LH_DefaultDomain_3&hash=item51964e07a3#ht_1212wt_754

Wheelnut · 24-06-2011 05:24PM

Totally different to mine.

Dean is probably right. I've looked at the RealOEM diagrams for the belt and the A/C pump and neither of them show any adjuster. Here's the diagram but it's no help:
http://realoem.com/bmw/partgrp.do?model=VC32&mospid=48480&hg=11&fg=18

Slidey · 24-06-2011 07:34PM

If the car is a manual, put it in reverse gear with handbrake off, put pressure on the belt in the direction to take it off and start to push the car backwards.

BMW E90 320d belt removal

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