034Motorsport Silicone Crankcase Breather Hose Kit for Audi A4 and A4 Quattro 1.8T (2003) and Volkswagen Passat 1.8T (2003–2005)

For the 1.8T engines in the 2003 Audi A4 and A4 Quattro and the 2003–2005 Volkswagen Passat, the 034Motorsport Silicone Crankcase Breather Hose Kit replaces the whole factory breather hose system with silicone hoses and a simpler layout. Crankcase breather hoses carry pressurized blow-by gases from the crankcase to the PCV valve, which separates out oil vapor and sends the air back into the intake. On these engines the factory plastic and rubber pieces become brittle and crack from heat, oil vapor, and pressure. The kit replaces six factory parts, and the stock PCV valve gives way to a 034Motorsport billet PCV valve. A billet aluminum block breather adapter with an o-ring seal and a cap/plug for the auxiliary check valve hose complete the kit. It is made in the United States.

034Motorsport covers this kit with a 24-month warranty.

This kit is 48-state legal but not C.A.R.B. approved, so it is not legal to install on cars registered in California or New York. On the Audi side it covers only A4 1.8T cars with the AMB engine in VIN range 8E-3-040000 to 8E-3-500000. Later A4 cars use 034-101-3003, which pairs with a different set of factory hoses and PCV valve. On the Passat it covers 1.8T cars with the AWM engine. Factory parts replaced:

• Valve cover breather hose 06B 103 221F
• Check valve to intake manifold hose 06B 103 224C
• T-hose 06A 103 247
• Block breather tube 06A 103 213AM
• Valve cover breather tube 06B 103 213AK
• PCV valve 06B 103 245, replaced by the billet PCV valve

Technical Details

• Manufacturer: 034Motorsport
• Part number: 034-101-3004
• Hose material: silicone
• Block breather adapter: billet aluminum with o-ring seal
• Engine codes: AMB (Audi), AWM (Volkswagen)
• Emissions status: 48-state legal, not C.A.R.B. approved
• Made in the United States
• Warranty: 24 months

Installation & Tuning Notes

The kit includes all the hardware needed to convert to the simpler breather layout. The billet block breather adapter reuses the factory retaining clip. The supplied cap/plug eliminates the auxiliary check valve hose rather than replacing it.

Common Questions

What symptoms point to a failed breather hose?
Common signs include a check engine light for an intake air leak, rough running or misfire, and oil residue on the hose or nearby engine parts.

Can I install it in California?
No. It is not C.A.R.B. approved and is not legal for installation on California or New York cars.

PMB Performance sells 034Motorsport engine parts for Audi and Volkswagen 1.8T owners.

Fitment & Compatibility

Check the fitment table below for your model and year. Audi owners should confirm the AMB engine code and a VIN between 8E-3-040000 and 8E-3-500000. PMB can confirm fit by VIN.