K-Seal Coolant Leak, 236ml | Multi-use Car Radiator & Head Gasket Repair Sealant

A mechanic recommended it after I sought help with a coolant leak. Couldn’t figure out where exactly the leak was. Was unable to locate any visible leak. The Color of exhaust smoke gave no indication(no white smoke). Engine oil looked ok. Tried it as a last resort than having to spend a lot more on replacing engine head gasket. Worked for my car. No more coolant leak. 🤞🤞🤞

Great product. I had a difficult to locate leak on my cooling system, the tank was empty/below the minimum line every morning. I topped up with new coolant to minimum, added all the KSEAL, then finished topping up with coolant to just above the max line & took the car for a good half an hour drive with the heating cranked up to max for the duration of the drive. Check my levels this morning & I haven't lost any coolant overnight. Perfect product for fixing the job.

Seemed to be working, naturally the full extent can’t be measured, but didn’t regret the purchase, good value for money, worth a try to be honest, easy to use.

This really does work!!! My car has been leaking coolant for a few weeks now and I have been topping it up every few days with coolant until I had a chance to take it to the local garage. Then I found this small little bottle of K-seal and it does exactly what it says. When it was delivered and I saw how small the bottle was I thought oh no! But I shook the bottle and added it to my coolant tank. It’s been one week now and the coolant level is still the same. Not dropped at all. Hopefully I won’t need to buy it again but I will definitely recommend it. Give it a go it’s SO much cheaper than a trip to the garage!!!

If you use this product PROPERLY it will work for you. Many of the horror stories you hear about this product if you do a little searching is quite frankly due to the total ineptitude and foolishness of the user. You see this product is fundamentally aimed primarily a vehicles with LARGE engines. You absolutely MUST find out what volume of water your engine uses and then use ONLY the recommended amount of the product to suit! - even if it seems tOo small an amount - you must be accurate AND follow the instructions. If you have a standard MEDIUM engined UK car and you dump the whole lot into your cooling system you are asking for trouble! Use the right amount and if your engines issue is still in the minor stages; you will see good results. Here's my particular situation. Nissan xtrail - petrol - when left standing for a few days upon starting would misfire and hesitate for about 10-20 seconds and then work fine. This is indicative of the head gasket on it's way out gradually weeping coolant into the piston chamber. When you start the car the plug is soaked with water - can't spark and you will get a misfire. As the other piston chambers are fine they get things moving - the water is eventually eliminated out of the exhaust port and the plug dries up sparks and then things carry on as normal. This was confirmed with low water in the radiator and header tank and using an inspection camera down the plug hole to confirm presence of coolant. Got new coolant - added the REQUIRED amount of the product - applied as directed and went for a drive as recommended. RESULT? - No more issues. Coolant levels no longer drop in the header tank and expensive repairs have been offset for a future time (if at all) - as this car has done 150K if I can avoid needing the head gasket being fixed before the vehicle becomes no longer worth running then I have saved a LOT of money.

Does not fix oil to water leaks

Well well well, this small bottle of liquid worked perfectly, and months later still no leaks. So happy

I used K-Seal for a radiator leak before I could get the car into a garage for a proper repair, and it worked well in the short term. It stopped the leak and gave me enough time to arrange a permanent fix without constantly worrying about losing coolant. That said, it is important to understand what this product is. It is not an end-all solution and it should not be treated as a replacement for repairing the actual problem. It is more of a temporary measure or a way to buy some time before getting the issue properly diagnosed and fixed. For what it is designed for, it does the job well. Just don’t expect it to magically repair a major cooling system fault permanently. A useful product to keep as a temporary emergency fix, but always follow up with a proper repair.

Seems to stop leaking from plastic header of the radiator.

Salut à tous j'ai acheté le 16 Mars 2026 il a duré 4 mois sur ma clio 2 phase 2 de 2003 pour moi excellent produit et simple a utiliser juste a mettre dans le bol de liquide refroidissement voilà

merhaba aracımda 2-3 günde 50-60 km kullanım sonrasında 500 ml kadar ciddi bir su eksiltme problemi vardı 20 şubat günü ürünü kullanım talimatına uygun olarak yedek depo içinde full antifiriz varken kullandım ilk kullanım sonrası 250 ml kadar bir eksiltme yaptı üzerini max çizgisine kadar tekrar antifiriz ile tamamladım 45 gün kadar oldu her hangi bir eksiltme olmadı şu an için daha önce kulladığım bir çok üründen daha başarılı

Ich habe dieses Produkt bereits mehrfach bei verschiedenen Fahrzeugen verwendet. Es hat jedes Mal zuverlässig funktioniert und kleinere Undichtigkeiten im Kühlsystem erfolgreich abgedichtet. Die Anwendung ist einfach und das Produkt hat sich für mich bewährt. Ich bin sehr zufrieden und kann es weiterempfehlen.

Fungerade mycket bra. Jag är nöjd. Bara att skaka burke jättenoga först. Sen hel i allt