ST5516 Heavy-Duty Multi-Purpose One Step Permanent Coolant Leak Repair, 16 oz, Pour and Go, Mixes with All Antifreeze, No Flushing Required

Vehicle leaking coolant, about 1gal per 1,000 mi driven. Dealer diagnosed as jiffy tight fittings on turbos with a repair estimate of $3,300. 2015 Ford F-150 - 3.5L Ecoboost with 140K miles so didn't want to put that kind of cash into a high mileage vehicle. Added as directed and leaks stopped immediately. 1K miles later, coolant level in the overflow tank has not gone down at all.

Had coolant leaking from water pump seal on a 2017 Ford Explorer. Used per directions and the leak stopped. A lot cheaper than replacing a water pump.

I just concluded a 7,000 mile drive from Georgia to Oklahoma, then to Cali and from there, Washington state and then back to Georgia in my 2002 Chevy Tahoe while hauling a 21' toy hauler heavy laden with toys. My Tahoe has an aftermarket radiator that produced a pinhole leak during travel. I couldn't directly locate the leak nor was I able to just replace the radiator as I was traveling. So I considered using a radiator stop leak but hesitant to do so as I didn't want to plug up my cooling system at all. I found this product and due to the reviews, decided to try it. It worked almost immediately after running the engine for a while to circulate the solution. And it still has not shown signs of leaking and no affect of the cooling capabilities either. I highly recommend this product!

Works great

I waited 5 days to write this review on my birthday. Mainly because I am so impressed with this product and I didn't know that it would hold. I'm not getting paid for this review and I rarely write reviews. A little history. I own a 2007 Mercedes E-63. This car is a beast and is a joy to drive. The dealership diagnosed a blown head gasket on the car. The report shows coolant mixed with the engine oil. My oil almost looked like a mocha espresso. A very bad sign. The car was immediately overheating. I was adding antifreeze every day. The dealership estimated repairs to start at $15K but could easily rise to $25K. Once the top of the motor is opened up I'm sure they would recommend new cams (4), new cam adjusters and of course new seals. A new crate engine for this car from Mercedes-Benz costs $57,000.00. After carefully reading the directions I added coolant with the bottle of K-seal after shaking it for 1 minute. Then I drove the car normally for 20-25 minutes. The car came up to temperature and stayed there. It didn't overheat! After feeling terribly about having to sell the car as a mechanic's special or donating the car I can instead enjoy driving the car daily. I did end up changing the oil 3 times before it didn't appear to have any more coolant in it. Thanks K-seal!

Awesome!! Saved me lots of work and money. Worked just as they said it would.

Does not work for over pressurized coolant system caused by exhaust gases getting into the coolant system. Followed the directions to the letter for over pressurization leak but to no avail, K-Seal did not work for my issue.

I had a leaky water pump on my rv. Nobody wanted to change it because it's very hard to get at and requires a radiator removal. I use this product and it sealed up perfect. Not a leak.