VW MK4 How To Change The Diverter Valve In A 1.8T


Thanks to rockon217 from the ‘tex for this DIY that explains how to replace the stock diverter valve on a 1.8T

    Category: Engine
    Difficulty: Easy Easy
    Original Author: rockon217

NOTE: Most of what is shown here is applicable to all 1.8T engines.


Valve replacement toolsHere’s a list of recommended tools to complete this job:

1) Flat-head screwdriver
2) Diagonal cutters (Needle nose pliers, tin snips, or a Dremel with a cutting disc will also work)
3) A small amount of motor or vegetable oil (this makes attaching the hoses easier)


Diverter valve partsHere are the parts needed for this project:

1) OEM TT bypass valve (Part # 06A 145 710 N)
2) Two 1¼” hose clamps
3) One ¾” hose clamp


DISCLAIMER: No warranty or guarantee is provided for the information provided on this site; you use it at your own risk. Although contributors to DIYNexus have an impressive depth of knowledge, neither they, nor DIYNexus can be held liable for any technical inaccuracies, typographical errors or consequences from the use of this information. Depending on the project, it is possible to void your factory warranty, disable a safety feature, create a hazardous condition, be injured or killed. 🙁 If you are uncomfortable or inexperienced working with anything described on this site, please consider having the work done professionally.

Engine cover removal1) Open the hood and you’re presented with a plastic engine cover. To remove it, use the flat-head screwdriver to turn each of the four hold-down screws ¼ turn counterclockwise. Then, lift the cover straight off.

Diverter location2) With the engine cover off, you can locate the stock diverter valve on the upper-right side of the engine.

Clamp locations3) Now we need to remove the hoses from the stock diverter valve. To do this, you will need to cut off the three one-time use clamps, identified in the picture. Use the diagonal cutters to cut/pry/break the clamps and remove them. You can also used a Dremel, an air cutter, tin snips, etc. NOTE: Be very careful not to damage the hoses when cutting off these clamps.

New clamps4) Remove the hoses from the top, bottom and side nipples and set the valve aside. NOTE: Be careful NOT to drop anything into these open hoses! Install two larger clamps on to the bottom and side hoses.
In the picture, the author already has the small hose clamp on the top hose. Do not do this yet because you will risk dropping the small hose clamp into the open hose on the bottom.

Lube valve5) Lightly coat the bottom and side nipple of the new diverter valve with oil, as shown in this picture. This lubrication will help it slide into the hoses.

Clamps installed6) Install the new diverter valve on to the bottom and side hoses. Then, put the small hose clamp on the upper hose and install it on the top nipple. Tighten all three hose clamps.

7) Reinstall your engine cover (doing the reverse of Step #1) and you’re done!


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