Coolant Leak From the Rear of the Engine Block?

Replace One of the Most Common VW/Audi 1.8T Cooling System Failure Points.

The factory coolant J plug seals a coolant passage located near the engine block and coolant regulator housing.

Over time, exposure to:

• hot coolant
• repeated heat cycles
• engine vibration
• aging plastic materials
• cooling system pressure

can cause the original plug to:

• crack
• become brittle
• leak coolant
• split around the sealing area
• fail without warning

A failing coolant J plug may cause:

✔ Coolant leaks behind the engine
✔ Low coolant level warnings
✔ Coolant smell from engine bay
✔ Overheating risk
✔ Cracked or brittle plastic plug
✔ Sudden coolant loss

This OEM-style coolant block plug is designed to restore proper cooling system sealing and prevent recurring coolant leaks.

Manufactured from durable heat-resistant automotive-grade materials, it provides reliable direct-fit installation for selected Volkswagen and Audi vehicles.

Key Features & Benefits

✔ OEM-style aftermarket replacement
✔ Restores proper coolant sealing
✔ Helps eliminate coolant leaks
✔ Heat-resistant construction
✔ Resistant to cracking and coolant pressure
✔ Direct-fit installation
✔ No modification required
✔ Ideal preventative replacement for aging 1.8T engines

Product Specifications

Part Type:
Coolant J Plug / Crankcase Plug / Engine Block Plug

Material:
Heat-Resistant Automotive Polymer

Reference OE Part Numbers:

• 06B103033C
• 06B103033A
• 06B103035

Compatible With Selected Models

Volkswagen

• Passat
• Touran
• Golf
• Jetta
• Bora

Audi

• A4
• A4 Quattro

Skoda / SEAT

• Octavia
• Leon

Compatible with selected:

• 1.8T
• EA113 engine applications

ECS Tuning identifies 06B103033A as the coolant “J” plug used near the coolant regulator on VW/Audi 1.8T engines.

German Auto Parts and Pelican Parts also list fitment for Audi A4 1.8T applications using this crankcase/coolant plug design.