Is K-Seal a temporary fix?
Sarah Scott
Updated on May 09, 2026
Just Pour & Go
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.How long does K-Seal last?
So I didn't need to, but I would recommend you replace your radiator cap before you try this, or if you know it's bad enough, in conjunction with the K-Seal unless you've replaced your radiator cap within no more than the past 2 years.Does K-Seal work permanently?
Testing by Brighton University showed K-Seal is capable of permanently sealing holes of up to 0.635mm in diameter, and cracks up to 0.254mm wide by 12.7mm long. As most holes and cracks are significantly smaller than this, K-Seal can provide a permanent, guaranteed fix for the majority of leaks.Can you drive after using K-Seal?
Just use the vehicle as you would for up to ten days after and if K-Seal has not made a repair then it is, unfortunately, unlikely to do so.How fast does K-Seal work?
It'll take 5 minutes for your engine to reach operating temperature.How to use K-Seal URGENT Watch before you damage your Engine, radiator leak repair fix correctly
Will K-Seal hurt my engine?
No. Scientifically tested, K‑Seal will not cause any harm to your car or its engine, nor will it damage the pump. It simply does what it says on the bottle: seals holes in your coolant system and cracks in your head gasket with ease, without the risk of blockages.Which is better K-Seal or bars leak?
#1 Best Overall: Bar's Leaks Liquid Aluminum Stop Leak. #2 Runner-Up: K-Seal ST5501 Pour & Go Leak Repair. #3 Best Powder: AlumAseal Radiator Stop Leak Powder. #4 Best Tablet: Bar's Leaks HDC Radiator Stop Leak Tablet.Will K-Seal fix a cracked head?
K-Seal Ultimate is the simple, permanent fix for blown head gaskets, cracked heads and blocks, and porous engine blocks. Our unique formula works with all water-cooled engines – there's no need to drain or flush your cooling system, and it doesn't matter what kind of antifreeze or coolant you've used previously.Will K-Seal stop a water pump leak?
K-Seal can repair most leaks in your engine's water pump casing and seals.What size leak can K-Seal fix?
Testing by Brighton University showed K-Seal is capable of permanently sealing holes of up to 0.635mm in diameter, and cracks up to 0.254mm wide by 12.7mm long. As most holes and cracks are significantly smaller than this, K-Seal can provide a permanent, guaranteed fix for the majority of leaks.Can I put K-Seal in my coolant reservoir?
K-Seal products are compatible with all types of antifreeze/coolant and are not affected by other additives that may already be in the cooling system.Can I use K-Seal twice?
Usually you pour the entire contents into the cooling system, so No you can't. Unless you can figure a way to filter it out of the cooling system to re-use it – in which case the cooling system/head gasket would leak again anyway.How long will head gasket sealer last?
Most sealants offer permanent solutions to minor leaks but can only last for a maximum of six months if the damage is severe.Will radiator stop leak harm my engine?
When you carefully follow the instructions for our engine, radiator or other stop leak products, there is no risk of damage. Always remember these points: Bar's Leaks stop leak products work for small to moderate leaks.What is the best engine stop leak?
If you're looking for universal protection, then Lucas Oil 10278 Engine Oil Stop Leak is the best engine oil stop leak product on the market. Customers who want to stop leaks and save money should use ATP AT-205 Re-Seal Stops Leaks.Which K-Seal is best?
Size Matters
- K-Seal is best used in cars, vans, light trucks and motorbikes with cooling systems up to 20 litres/21 quarts.
- K-Seal HD (Heavy Duty) is best used in large trucks, tractors, heavy plant and other heavy duty engines with cooling systems up to 57 litres/60 quarts.
