T25,T4,G1,G2,G3 Rocker Cover Breather Seal

This rocker cover breather seal is a small but essential gasket that fits under/around the breather valve on the top of the rocker (valve/cylinder head) cover. Its job is to create an airtight and oil-tight seal where the breather assembly mounts to the cover, ensuring the crankcase ventilation system can work correctly without oil misting, fumes, or vacuum/pressure leaks.

On many VW petrol and diesel engines, crankcase vapours are routed through the rocker cover breather. When this seal goes hard, shrinks, or splits with age, it commonly causes:

• Oil seepage/misting around the top of the engine

• Oily engine bay and dirt build-up around the breather area

• Breather fumes escaping under the bonnet

• Poor crankcase control (which can contribute to weeping gaskets elsewhere)

Replacing the seal restores the correct fit of the breather valve and helps maintain proper crankcase ventilation, keeping your engine bay cleaner and your breather system functioning as intended—ideal for routine servicing or restorations.

What it does / how it works

• Sits between the breather valve and the rocker/valve cover

• Compresses when the breather is fitted, forming a tight seal

• Prevents oil vapour leaks while keeping crankcase ventilation flowing correctly

Fitting notes (recommended)

• Clean the rocker cover breather seat before fitting

• Check the breather valve itself for blockage/sludge while you’re there

• Inspect breather hoses for splits (a failed seal is often found alongside brittle hoses)

• Fit square and evenly to avoid pinching the seal

Full Vehicle Fitment Details (Models / Years / Engines)

VW T3 / T25 (Transporter)

Diesel – 1982–1992

• 1.6 Diesel: CS

• 1.6 Turbo Diesel: JX

VW Corrado (1989–1995)

• 1.8 G60: PG

• 2.0 8v: 2E, ADY

VW Golf Mk1 Cabriolet (1982–1993)

VW Golf/Jetta Mk2 (1984–1992)

Petrol

• 1.8: EV, GZ, GX, HT, RG, PB, PF, RV

• 1.8 G60: PG

Diesel / Turbo Diesel

• 1.6 Diesel / TD: JR, 1V, MF, RA, SB

VW Golf/Vento Mk3 (1992–1998)

Diesel / TD / TDI / SDI

• 1.9 D/SDI/TD/TDI: 1Y, AEY, AAZ, 1Z, AHU, ALE, AFN

VW Golf/Bora Mk4 (1998–2006)

1.9 Diesel family

• AGP, AQM (SDI)

• AGR, ALH, AHF, ASV (TDI)

VW Polo Mk3 6N (1995–2002)

Diesel/SDI

• AHG, AKU, AEF, AGD

VW Caddy (Caddy II / Caddy III)

• Caddy II: 1995–2004

• Caddy III: 2005–2009

VW Passat

• Passat B3/B4: 1989–1997

• Passat B5 (3B): 1996–2000

VW Transporter T4 (1991–2003)

Diesel / Petrol

• 1.9 TD: ABL

• 2.0 Petrol: AAC

• 2.4: AAB, AJA

• 2.5 Petrol: AET, AEU

• 2.5 TDI: AJT, ACV, AHY