# Bentley manual error -- my baby's crippled



## RKT BMR (Sep 7, 2002)

Gang, I wanted to alert you to a problem in the Bentley manual that may prove to be very expensive.

As many of you know, I installed an ESS Supercharger 7 months ago. I have about 8000 miles on it at this point, and it has been pure pleasure. Haven't had any problem with it at all.

The SC is still fine. However, my motor is not. What broke this weekend could happen to anyone who is removing and replacing the serpentine belt on the front of the motor for any reason, not just adding a blower. A 4"x3/4" piece of cast aluminum broke off where the belt tensioner bolts on to the front of the engine -- containing half the threaded hole for one of the attachement bolts.

This happened because the description in the Bentley manual for how to release this tensioner and remove the belt is wrong -- at least for my 5/01 production 330cic. BMW apparently changed the tensioner design, switching to a piston/spring design which is mechanically more complicated than the simple spiral spring design that is still used for the AC compressor belt tensioner (and which Bentley shows as the serpentine tensioner as well). So, when following the instructions in the Bentley manual, I tried to turn this bolt to relieve the spring, when in fact I was just overtightening the tensioner mounting bolt.

After about a half turn and no release of the belt tension, I decided something must be wrong. Backed the bolt off a 1/2 turn, and called BMW to speak to a mechanic. Found out what to do, and the install of the SC proceeded successfully from there.

However, this over-torqueing of the bolt apparently stressed the cast aluminum mounting point, which eventually failed. Looks to me like this is a seperate piece, so I'm keeping my fingers crossed that it can be replaced without too much monkeying around. Worst case, though, the motor might have to be pulled, the front pulled off and replaced, etc. Sh*t, I just don't know yet.

Anyway, I hope I can help someone else avoid a similar disaster by sharing this. BMW is very specific about torque values for tightening virtually every bolt, screw, and nut in the car. Now I know why. :bawling:


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## in_d_haus (Jan 2, 2002)

Did you contace Bentley about this?


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## Mpwrlftr (Jan 20, 2003)

Don't be hard on yourself, you're not the first to fall into this Bentley trap. I was trying the same bolt when I did my pulleys but lucky for me I stopped and backed off on that bad boy when results weren't forthcoming. I've sheared off many a bolt in my time and I'm very timid now.  
I've read other posts about this problem. Good luck and hope it's a minor fix.


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## Parump (Dec 25, 2001)

Yikes. I hope that the repair is not expensive.


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## RKT BMR (Sep 7, 2002)

in_d_haus said:


> *Did you contace Bentley about this? *


No, but I suppose I should just to at least attempt to get them to corect it in a future edition.

As for getting relief from them, no chance. They very clearly weasel out of any potential problems like this with a disclaimer at the beginning of the manual, essentially telling you that you rely on the information therein at your own risk. :thumbdwn:


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## SteveMD (Apr 22, 2002)

Tell Bentley to get their ass over here and read your post and this reply.

Their E34 5 series manual specs wrong torque for the M30 engine ignition rotor adapter hex bolt that goes into the front of the camshaft. Same problem results: over-torquing!


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## The HACK (Dec 19, 2001)

Man that sux. Don't be TOO harsh on the Bentley manual though, because it was published well before your car was produced and it's hard for them to cover everything. BMW changes design and production of various parts on these cars on a regular basis and it's nearly impossible for anyone publishing a 3rd party repair manual to keep up.

This is probably a little too late for comfort, but I think it would be in your best interest to subscribe to the TIS CD in addition to the Bentley's manual, if your car is 2001 or later.


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## RKT BMR (Sep 7, 2002)

The HACK said:


> *This is probably a little too late for comfort, but I think it would be in your best interest to subscribe to the TIS CD in addition to the Bentley's manual, if your car is 2001 or later. *


Well, subscription is probably too expensive, but this incident has motivated me to nab a dated copy from eBay, and I plan to update myself that way once a quarter or so.

Since I don't have a copy, I can't tell how major a part that aluminum casting is where the circled A is... Anyone with an ETK (or whatever that parts CD is called) care to capture a picture of the part and post it?

I'm fearful that it's a single piece that includes the oil filter housing, the timing chain cover, and (God forbid!) the oilpan too. Would have to pull the engine to replace it.

I'm holding out hope that it's just a smaller piece bolted on, and can be removed and replaced without too much hassle. The car's in the garage until I can make this determination, which greatly effects whether I can fix it myself or not.

:bawling: Dave :bawling:


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## The HACK (Dec 19, 2001)

For some reason the images show up as big red Xes for me...

Email them to me, [email protected] and I can try looking it up for you.


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## RKT BMR (Sep 7, 2002)

Mucho thanks to Kaz and Hack for helping me sort this out. Kaz did some investigative work under the hood, and Hack tracked down the part in the ETK. Looks like I'll be able to fix this myself over a weekend, but it'll be a pain. However, most of the cost to have someone else do it will be labor, and with the SC in there, even more $$ to take it out and put it back -- and only *I* will do it right 

Here's a little animation of the part, and where it broke, for those interested. The whole thing is referred to as the oil filter housing.


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## RKT BMR (Sep 7, 2002)

Now that I got my hosting problems fixed, I thought I'd circle back and post pictures that I couldn't get to work weeks ago for those interested. So, here we go!

This picture is for orientation. The front bumber is is in the direction of the bottom of the image:










This shows the area where the damage was. The part that broke is just behind the spot where the mounting bolt runs through the tensioner, and is the left hand side of the thread hole. You can't really see it in this picture, because it's behind the tensioner assembly.










The next two images should make it clear what broke. The image above still has the tensioner mounted with its other two mounting bolts; in these images, the tensioner has been removed.



















Here's a shot of the piece that broke off, and the mounting bolt, with a tape measure for scale.










Anotner shot of the broken piece:










Damage to the water pump pulley from contact with the tensioner assembly when the mount point failed:










[continued in next reply...]


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## RKT BMR (Sep 7, 2002)

[continued from previous post]

The damage to the pulley and the oil filter housing turned out not to be the the full extent of the damage. After I got the tension off, I discovered that it too had been trashed. Here is a picture of what it looks like from the front:










No problem, eh? Well, turn it over and look at it from the back!










Fortunately, the tensioner can be disassembled, and rebuilt, so I didn't have to replace the whole thing, which would have cost several hundred $$. In this case, the broken piece is a replaceable part, the tensioner "base plate", $50.

For a detailed look at the oil filter housing that was replaced, go here.


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## HiMiles (Jan 11, 2003)

*Hat's Off*

Impressive work on the car.. I'm glad you were able to fix the problem yourself, no matter how much it's going to cost. At least, you will replace what needs to be replaced 
Great job, and thanks for sharing the info bro :thumbup:


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## Parump (Dec 25, 2001)

Thank you for posting the images and your experiences. I had been hoping that you would provide us with an update. Congratulations with your ability to repair the problem yourself!


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