Permanent Coolant Leak Repair with K-Seal Coolant leaks don’t have to result in costly repair bills – simply add K-Seal to your coolant system for a quick and permanent fix. K-Seal is scientifically tested, trusted by millions of customers worldwide, and the only coolant leak repair fluid carried by the AA, the UK’s largest roadside repair company. Just pour & go! K-Seal couldn’t be simpler to use. Just shake the bottle, add the fluid to your coolant system, and run your engine as normal. K-Seal’s unique formula will seek out holes and cracks, and permanently seal them, with no adverse impact on the efficiency of your engine cooling.