Holts Wondarweld 500mlPRODUCT DETAILS:Holts Wondarweld is a professional cooling system repair product that?s designed to fix small cracks and holes in the cylinder head, engine block and head gasket.Thanks to its heavy-duty formula, the product provides a permanent repair without causing damage or clogging the system, so you can fix small problems without the need for a costly repair.Heavy-duty crack repairRepairs cracks in engine blocks, cylinder head gaskets and water pump gasketsNo clogging or damaging effectSuitable for steel, aluminium, and iron enginesWondarweld is one of our most heavy duty repair products, which offers a quick way to fix big jobs. Leaks in areas such as cylinder blocks can be expensive to fix at a garage, but Wondarweld lets you carry out the repairs easily at home.Just pour in the sealant without draining or flushing, and Wondarweld seals the leaks quickly. You can trust Wondarweld to fix leaks safely without causing damage or clogging to other parts of the system, getting you back on the road. Read the instructions on the back of pack carefully and do not pour into oil. Wondarweld fixes leaks in:.