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

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!

The stuff worked, stopped the leak. Not sure how long it will last but has been 5 days of driving normally. It was really simple by pouring into radiator!!

I can’t say it worked 100%. I was not able to have the product work completely into the system to have it work fully. But it did slow down the leak to where I was only putting 1 gallon of coolant instead of 2 gallons of coolant a day into my truck.I end up getting repairs done sooner than I wanted. One of the seals had a crack in it. That’s why it was leaking coolant into my oil.But the stuff gets all through your system, and I had to flush everything out.It did end up in my oil pan. It did not seem to cause any harm to the system at all.It was easy to pour into the reservoir tank.When you look into the reservoir tank, you can see the small particles of copper.It did not seem to cause my heat level to rise either.

Works great

Didn’t fix my problem but I’m sure my issue was more than a miracle fix can do.

did not work for me. i had a small leak coming from the corner of my radiator so i honestly thought with how small the leak is that instead of wasting money on a new radiator i would just buy this stuff. turns out it was just a waste of money and i would have been better off just buying a new radiator.

Had a decent radiator drip on my RV. It is a huge radiator, 4 feet wide. I was going to get the radiator removed and fixed at a radiator repair place but it was so large I couldn't get it out of the bottom of the RV without jacking it up 2 feet.I was skeptical to try this K-Seal but the advertising said it could handle the heavy duty capacity of my 15 liter Cummins ISX diesel size, so I tried it.Within 25 minutes the leak was gone, pretty amazing. I let it run for an hour just to be sure. I will be driving it to a race soon and make sure it stays fixed.Happy that I didn't have to remove radiator, saved myself 10 hours of labor and hundreds of dollars to repair.

The media could not be loaded. So I have a 2005 Chrysler Pacifica, with about 206,000 miles. For the last 2 years I've been fighting this leak through the intake manifold gasket, where I would have to put in about of quart of coolant every 3 days. I've been working on cars all my life so I know how hard it is to change a head gasket or even a intake manifold gasket. Throughout the two years I've been using J-B weld aluminum extreme heat which were only suppressed the leak for about 2 months at a time. After doing a little bit of research I came across this product. Started watching videos and reading testimonials. I was like what the heck let me try it. The leak would occur usually about three to five minutes after I start my car. I added a little bit more coolant, and started my car. I followed the instructions shaking the bottle for 30 seconds vigorously and proceeded to pour the whole bottle into the reservoir tank. My car was really low on coolant so when I added the k seal it went directly from the reservoir into the block. I added a little more coolant to top the reservoir tank off and and place the cap back on the reservoir. At this point my car had already been running for about 5 minutes and what do you know not a trace of coolant was leaking. Like I said before this been happening for 2 years so I know that the coolant should have been leaking by now. So I let the car run for 30 minutes. I turned on the heat full blast just so it wouldn't get clogged into the coils of the heater core. Usually about 30 minutes of running my car the coolant would have been pouring out of the gasket in between the intake manifold and the head. There was no leak at all. After close inspection the area was bone dry. I have never witnessed a product that can fit fix a gasket leak like this one. It literally save me about $1,500 in costly repairs, actually would have been less because I would have been fixing it myself ,but still save me about 5 to 8 hours of labor. So my review for this product is definitely 5 stars and it definitely worked in my situation. I will update this in about 30 days. See the video for yourself.UPDATE: As of today, (May 19th). the leak is still sealed. It's been about 45 days and the seal is still going strong!