B7 A4 Catch Can Instructions

Thank you for purchasing a BSH Catch Can kit for your Audi A4. The kit should include
the following components. Please make sure they are all in the box before continuing. If
you bought any additional upgrades their specific parts list will be included separately.
Required tools are not included.

Parts Tools
PCV Nipple 3/32 Allen Wren
PCV Guidance Block ¼ Allen Wrench
Manifold Block Off Plug T25 Torx
3 Set screws for Block Off Plug 17mm Wrench
One O-Ring for Block Off Plug Flat Head Screw Driver
Catch Can Phillips Head Screwdriver
Lines Blue Loctite
Three clamps  
One 90 degree fitting  
Two straight fittings  
One Drain Valve  
Catch Can Bracket  
One allen head screw with matching lock nut  


Step 1: Remove factory accordion hose that leads from the Intake manifold to the Front
PCV assembly. This is done by pinching the connectors on both sides and pulling away.


Step 2: Install the manifold block off plug. Make sure the O-ring is properly seated in its groove before installing. Apply a dab of motor oil to the O-ring to help it slide on. It is
easiest to install by doing a slight twisting motion. When you have it on the manifold,look at the opening on the plug and make sure the bolt holes have cleared the lip on the manifold. When this is done, apply a small drop of blue loctite to each one of the set screws. When installing the set screws DO NOT TIGHTEN THEM. These screws hold the cap in place by locking it against the lip on the manifold. There is no need to apply force to them. Allow the loctite to dry before driving.


Step 3: Remove the front PCV assembly. Start by removing the hose on the driver side.
The clip that holds it in place has 4 teeth. Remove the side teeth and the top tooth by
gently lifting them up and over the lip on the nipple one at a time with your flat head
screwdriver. When those are free of the lip, slide it off. Be patient with it, don’t break the
clip. When the hose is removed, then remove the 4 T25 torx screws holding the front
PCV in place. Make sure to keep the screws as they will be re-used. With the screws
removed the front assembly will come off.


Step 4: Install the PCV Nipple and the PCV Guidance Block. You must do this as
follows for the part to fit properly. First install the PCV Nipple. Line it up and re-install
using the factory screws a couple starting with the top screw and then the bottom one.
Once installed and sitting flush reinstall the factory PCV hose. This is a tight fit and you
will want to guide the O-rings into the hole with the tip of your flat head screwdriver.

With the hose installed you can install the new guidance block. Begin by applying blue
loctite to the straight fittings and then threading them into the plate. When installing on
the valve cover, re-use the factory screws starting with the top screw and then the bottom


Note: Do not apply to much force to when re-installing the factory hardware. The needed
torque is 30 in/lbs so take it very easy on them.

Step 5: Install the 90 degree fitting on the top of the catch can. Apply a bit of blue loctite
before installing. Wrap the supplied adell clamp around the can just below the side fitting
and attach it to the supplied bracket using the allen screw and lock nut. Once secured to
the bracket it is time to install.


Step 6: Locate the Phillips Head screw on the factory coolant reservoir bracket. Remove
the screw and slide the bracket in between the coolant reservoir and the OEM bracket.
Line up the holes and tighten the factory screw back in place.


Step 7: Now run your lines. The fitting on the firewall side of the plate will be connected
to the side port of the catch can. The fitting on the radiator side will go to the top fitting
on the can. Leave just a little bit of slack to allow for engine movement. Once cut to
length, secure the lines with the supplied hose clamps. The side fitting does not require a
hose clamp. The picture below has the line lengths exaggerated to make it easier to
follow. Cut the lines to an attractive length.


Step 8: Start the car up and check for leaks. If the engine bucks or surges then you have a
leak and will need to make sure everything is seated properly. If you notice a putting
sound coming from your intake it is caused by the check valve in the PCV port on the
rear of the valve cover. This check valve is sealed at rest and when pressure builds up
behind it the valve will open creating a putt sound. This is not harmful and if found to be
an annoyance the check valve can be removed from the rear port.

Maintenance: For the first few weeks you have the can installed monitor how much
blowby you are collecting. You will need to monitor how much blowby from your
individual car ends up in the catch can and judge how often you need to drain. This will
vary from car to car.

You will collect a mixture of oil, water, and fuel vapor in your catch can. Expect the
quantity of water to greatly increase during the winter months.

Every 3-4 months remove the top fitting and clean out the can with brake cleaner. Also
clean out your catch can lines.

It is of utmost importance that you do not let the catch can reach full. If the can is allowed
to become full the crank case pressure will no longer be able to be vented which can lead
to engine problems.

**Important Note**
Customers in regions of the world that drop well into the freezing temperatures during the
winter will need to keep a watchful eye on the volume of water collected in the can. One
of the main fluids caught in the can is condensation (water). In the winter months the
amount of condensation caught in the can will dramatically increase. If left in the can in
freezing temperatures there is a possibility that this water could freeze. If frozen, pcv
flow will be inhibited. Make sure to keep an eye on your fluid levels.