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.

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!

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.

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.

My neighbour swears by it. Says it fixed the leak on his truck perfectly and that was a year ago and the fix is still holding up! He only used half the bottle too so he still has the other half left. We however did not have as much luck but that was our own fault! We had a small leak at first, if we had known about this product and used it then, I feel like it would have definingly solved our problem! But we unfortunately ran the truck to the point where all the anti-freeze leaked out because we had bad head gaskets and it over-heated the engine and then unfortunately this couldn't fix the major problem we created. I would definitely recommend this if you have a coolant leak, use it early it will definitely help!

I had an unsatisfactory result with one of my cars I earlier reviewed. However, I had a visible gakset leak between the plastic intake manifold and cylinder head in 2007 Town Car, and was about to remove it for servicing until I thought, let me give K-Seal another shot since I had a small quantity left. The result was magic! The leak is gone, and been running dry and clean for a month now.

There was a crack in head gasket of my car and coolant was leaking from there. Results in engine overheating. I added Kseal HD in in coolant and I had driven 5000 KM after that and crack is healed hence no overheating. Authorised service centre had asked to change the head gasket , that could have costed me around Rs. 75000. Local mechanic suggested to weld the crack. That too have costed around Rs. 20000. But Kseal costed me only Rs. 3500. And it really worked for me.

Funciona y es fácil de usar

It s not sealing coolant pump mild leaks.. I can only seal radiator leaks, not in other places- saying by my own experience.. if coolant pump leaks, u better repair it instead of wasting on it..