T4 Rocker Cover Pressure Regulating Valve Breather Hose - 1.9 Diesel (1X,ABL)

This crankcase ventilation hose is a direct replacement for Volkswagen T4 Transporter models fitted with 1.9 Diesel engines. The hose forms a key part of the engine’s crankcase breather system, allowing blow-by gases and oil vapour to be safely routed away from the crankcase and back into the intake system.

On 1.9 diesel T4 engines, these hoses are exposed to constant heat, oil vapour, and vibration. Over time they commonly become hard, brittle, or split, leading to oil leaks, excessive crankcase pressure, and poor engine breathing. If left unresolved, this can contribute to oil misting around the engine bay, increased oil consumption, and seal failure.

This replacement hose is manufactured to the correct internal diameter and length to ensure a proper seal and unrestricted flow, helping restore correct crankcase ventilation and reliable engine operation.

What this hose does

• Vents crankcase pressure safely from the engine

• Prevents oil vapour build-up and excess pressure

• Helps reduce oil leaks and seal failure

• Maintains correct engine breathing on diesel T4 models

How it works

During engine operation, a small amount of combustion gas escapes past the piston rings into the crankcase. This hose allows those gases to be vented through the breather system, preventing pressure build-up and returning vapours to be re-burned.

Fitting notes & recommended associated parts

• Inspect all breather hoses and junctions for brittleness

• Clean the oil separator/breather box if contaminated with sludge

• Replace hose clips if corroded or weak

• Ensure the hose is not kinked after installation

• Ideal to replace when addressing oil leaks or during engine servicing

Engine Compatibility

• Engine size: 1.9 Diesel

• Fuel type: Diesel

Full Vehicle Fitment Details

VW Transporter T4 / Type 70

1990 – 2003 | 1.9 Diesel

Body Styles:

• Bus

• Van

• Platform / Chassis

Production periods covered:

• 09/1990 – 12/1995

• 10/1992 – 04/2003

Power outputs:

• 60 PS

• 61 PS

• 68 PS

This hose is suitable for all listed 1.9 diesel T4 variants within the production ranges above.