Holts Wondarweld 250ml

Wondarweld is a professional cooling system repair product. It is a heavy duty repair which fixes cracks in cylinder heads, engine blocks and head gaskets permanently.

Once added to the engine, Wondarweld circulates through the cooling system, seeking out small holes, cracks, and leaks to form a permanent repair. Lab-developed to ensure maximum performance and longevity, the product is safe for use on all common engine materials, including steel, aluminium, and iron.

A 250 ml bottle of Wondarweld is sufficient for cooling systems up to 8-litre.

Before using Wondarweld, drain the cooling system and flush with Cooling System Flush to remove any residue and contaminants left behind by the old coolant. After draining, reattach the bottom hose.

To use Wondarweld, you’ll need to remove the top hose from the cylinder head outlet before removing the thermostat. Do this, then use a funnel to apply the product directly into the cylinder head outlet, taking care not to pour into oil as this can cause serious engine damage.

After applying the product, replace the thermostat and top hose. Refill the system with clean water and run the engine for 15 minutes to repair the leak.

When the repair is complete and no fluid is leaking, drain the system again, flush with clean water, and then top up with a high-quality coolant/antifreeze product (add link here for Prestone coolant).