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Old December 16th, 2008, 20:06   #1
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Post BHW Balance Shaft Module replacement

This thread is only for this topic. If you want to post about your car makng noises, see the links to other threads below and post in one of them.

As we learned from bad experiences, the BHW engine was equipped with at the factory with a chain driven balance shaft module. Chains and tensioners break, teeth strip off the sprockets, and nasty things happen to the engine.

VW obviously learned of this prone-to-failure design. Every engine they have with this design outside of North America got gear-driven balance shaft module replacements (not recalled, just replacement in the parts catalog and system). Finally they made one for the North American market BHW engine.

They issued a technical document to notify dealership shops of the replacement. However, they have not (as of this writing) actually made the information available via eBahn (the site they point to for everyone else to get repair info). The technical document merely states to refer to the repair manual for installation instructions. As of this writing, I am not aware that the information is actually there for North American VW repair technicians (I'm not one so I can't personally verify).

Oilhammer, who works at, was alerted to the replacement parts, and less-than-helpful bulletin. I was able to track down the repair procedure published elsewhere in the world. That procedure was lacking in some steps.

We obtained the necessary parts, and together we installed them on my 2004 Passat Variant. The document link below provides a PDF with the repair procedure.

It is a supplement to other repair procedures that need to be followed as a part of the balance shaft module replacement. The other procedures are documented in the repair manual for the Passats. These include removing the front bumper cover, putting the lock carrier in service position or removing entirely, suspending the engine, timing belt replacement, and manipulating the subframe. This document does describe the necessary steps to take for loosening the subframe enough to remove the oil pan.

Read through the procedure. If you do not understand it, or do not have the other repair information, we do NOT recommend that you undertake the procedure. Failure to reassemble the car correctly can lead to poor handling which might lead to an accident. Failure to correctly reassemble the engine could also lead to a catastrophic failure.

You have been warned. You take on all responsibility for following this procedure, and all consequences of working on your car.

Having written that, I have to say I am very pleased with the outcome. My engine was making a lot of noise. It had very noticeable chain noise, though nothing terribly wrong was found on disassembly. The engine has virtually no lower engine noise after the surgery. I don't have to worry about imminent chain failure.

Refer to the following threads for further information about balance shaft issues:

I may revise the document at any time. Please get a fresh copy before undertaking the repair on any vehicle.

This procedure can be followed as a guideline for the other engines of the world that got this replacement design. However the parts vary depending on the engine. Vehicle disassembly/reassembly may also vary.

BHW Balance Shaft Module Replacement Procedure PDF

This document is a fairly large size (1377.8kb).

Edit to add:
World IMPEX has put together a kit price of the parts for those of you who are unable to get to oilhammer for help.
Geared Balance shaft module kit can supply parts too.

Bora Parts offers kits.

I have no association with these companies.

Last edited by MOGolf; June 30th, 2009 at 14:40.
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