ST5501 Multi Purpose 1 Step Permanent Coolant Leak | Radiator Leak Repair for Car RV Truck Motorcycle Sealant for Cylinder Head, Engine Block & Water Pump

Excellent product. Worked wonders with my 2003 Volvo s60 with 261000 kms on the odometer. The engine head gasket had blown up causing water loss. K-seal sealed it in 20 minutes. After applying the fix I drove it for almost 100 kilometers and no water loss at all. Though I have to see how long it lasts. Six months since I used it and the car still runs great without issues.

I had a leak wasn't detectable, it drove me crazy, no white smoke and no sign of leak, every week i had to top up around 200ml coolant, even at garage wasn't found, and this little magic did stop the leak almsot a month and half no issue till end of July ++ Edit by August beginning Oil mixed with coolant , looks heat exchanger inner issue hop not followed by usage of this item!++ Edit Sep August End coolant pump stopped working, and thermostat and leak from Radiator after heat start to go up, unsure if system clogged, leak was mostly by Radiator damage but not visible because evaporated due engine heat and air flaw!

It killed my coolant leakage

Been 1 week, leak reduced. Hope will solve on long run too.

My car's engine water was needed to get refilled once in a week(I drive the car everyday almost 15km). I fed up and finally bought this product. It was my last chance before visiting the garage. I have tried this sealer with my car and amazingly it worked. I saved 1000$ by paying only 50$. Thanks.

The product wasn’t original because the seal was broken and re sealed with transparent tape.

Poured in my Chevy Cruze reservoir tank and worked. Past 2 weeks no visible leakage of coolant yet

didnt fix the leak

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

It actually worked , saved me $$$ in repair on my 11 year old chevy cruze at 189,000 miles . The coolant was leaking so much - that I had to refill every 2 weeks.

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.