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If you use ULTIMATE for a Head Gasket repair and it and it fails to fix the leak get in touch to find out about our money back guarantee. For all our other brands if you have a repair that subsequently fails contact us for a replacement bottle.
Reviews 493
Earl Whitehorn
Apr 18,2019This is not a review. I have not used the K-Seal yet. I just don’t know where to go to get my question answered. I have searched reviews and can’t find a similar problem. I have an older John Deere tractor.(4630) and it is leaking externally at the front between the head and the block. It is fine at idle or light load, but under heavy load it starts to weep pretty good. It doesn’t give any indication of an internal leak in to the oil. Will K-Seal work on an external leak like this? Thanks for the help.
Rick Wetzler
Apr 10,2019This is more of an inquiry and hopefully I will get a lot of input on this, including a response from Colin, the K-Seal representative. I have a very small leak somewhere in the block where oil gets in to my coolant, but there is no coolant in my oil. I did a block test to see if there was any exhaust gas in my coolant and there wasn't. So that pretty much eliminates a faulty head gasket, I guess. Also the car runs perfect, no check engine light, no visible exhaust at the tail pipe. That leads me to believe that I might have a tiny crack somewhere in a wall which separates the oil passages from the coolant passages. Will K-Seal fix something small like this? Also because there is oil in the coolant and not the other way around indicates that the pressure on the oil side is higher than on the coolant side.
Cliff
Apr 10,2019I had a leak, quite a substantial leak, on my VFR 1200 F, Honda motorcycle. The AA man got out of his cab shaking a bottle of K Seal. Hang on, I said, I want to check that it's ok to use it. Dealers want us to buy new stuff so didn't recommend it, so I got the bike recovered. But looking through the internet, consulting with other mechanics and then confirming that it has been thoroughly tested on motorcycles, I bought it and put it directly into my radiator via the filler cap. 5 minutes of running and the leak had stopped. I topped up twice (air blocks) and have done 1500 trouble free and leak free miles (in a month) since. Jolly happy - it cost me a bottle of K Seal as opposed to £700 for a new radiator plus fitting. The bike is running spot on. Thanks.
Elliott Turner
Mar 31,2019Used K-Seal on an '07 Civic. NTB said it was a water pump. I changed water pump and still had small leak. Discovered '06-'09 Civic's had recall for cracked blocks. Pressure checked revealed cracked block. 1 bottle of K-Seal has stopped leak. Hopefully it will last. I would recommend this product. UPDATE: One week and still no leaks. 🤞🏽 Update: 8 months still no coolant loss and block is still not leaking where it once was. Worked for my application. Update: had to add second bottle last month, no leaks now, still VERY pleased with product....
Ferry
Mar 25,2019I had a very small crack in a 1969 340 mopar engine. After reading horror story's on the internet about clogged up radiators i decided to give it a try before starting a expensive rebuild. I just mixed up two bottles antifreeze with one bottle Kseal and threw it right in to the engine block by removing the thermostat. It literally took seconds to stop the leak!! I can now just cruise this summer and collect the parts for a rebuild:)
Kyle
Mar 20,2019I have a seat leon mk2, and unfortunately a brick hit my radiator and put a crack in it.....decided to use k seal and with in 5 minutes the leak stopped, I have used k seal in a number of my cars over the years and its never failed me,i always keep a bottle in my glove box just in case something like this happens again... Thanks k seal
Marcus Haslam
Mar 20,2019K-seal was recommended to me by my local mechanic, as he has used K-seal products for years. Unfortunately on this occasion my blown gasket was just to far gone. True to their guarantee, K-seal refunded me for the cost of the sealant quickly and without fuss. If the occasion ever arose again with a different car, I would try K-Seal again
Jared Rose
Mar 17,2019I had just replaced the head gasket on my Audi TT MK1 only to find white smoke still billowing from the exhaust. As a last resort to save the engine, I bought K-Seal Ultimate. I was very skeptical of the product but hoped it would work. I followed the directions and after two cycles of heating the engine up to operating temperature and allowing for cooling in between the white smoke was completely gone. I only gave four rather than five stars because I can not speak as to how long it will work.
Dylan Coleman
Mar 16,2019Absolutely fantastic in the many applications I've use it I have always been very very impressed with the results recommended to all my friends has never let me down once !
Stan Claerbout
Mar 13,2019Our 2001 Suburban with 285K+ miles showed white exhaust smoke and creamy sludge on the underside of the oil fill cap. I had been adding water periodically for a year thinking maybe it was time for another water pump. Then it occurred to me that I had two separate head gasket leaks. That signaled the end of the line for the faithful 'Burb. But I tried a bottle of K-Seal after reading some reviews. Long story short, it took three bottles, thirty days, and helpful assistance from the K-Seal company to fix the problems, with virtually no effort except pouring the bottles into the cooling system. I have left the product in the system, and will remember to add a bottle of K-Seal to any vehicle I own with 75K miles as a preventive to seal head gasket leaks before symptoms appear.
John
Mar 12,2019After days of replacing parts turns out that the water pump was leaking! Poured in K Seal as a last resort and after 30 mins the coolant hasn't moved a millimetre!!!! Thank you soooooo much 5 stars
Whit
Mar 10,2019I have a 2005 Nissan Frontier 4.0L with 150k miles on it. I developed a coolant to oil problem and could not determine the cause; cracked block, blown head gasket, bad water pump (sense it is driven by the timing chain sprocket and exposed to oil). So I decided to go ahead and try the K Seal rather than spend time and money trying to ID the source. I drained a qt of coolant to make room for the K Seal and followed the instructions. After stopping the engine I drained the new oil I had put in and noticed how much better it looked than the previous (only slightly milky and that may have come from milky oil left in the engine internals). After an hour and engine cooled, I re-filled with new oil and filter and ran the engine to operating temp for about 5 minutes and shut the engine down. I pulled the dip stick and I couldn't believe my eyes. The oil was crystal clear, I actually had to touch it to make sure there was oil on it. Haven't driven it yet but am looking forward to many trouble free miles. Really great product. UPDATE: 2 wks and 150 miles later, everything is still great. Running like it should.
Gary Gottfredsen
Mar 09,2019I am very impressed! I have a Buick lesabre which when I bought it had no idea about any head gasket leak. Well shortly after found antifreeze being burned right at the head. I couldn't believe it. I don't have money to put into this car I just bought so I went against everyone's advice and I did it anyway. Almost immediately after I added k seal the leak was just gone! I was stunned! However, now I am worried that this product while taking care of my problem could cause other ones like internally with hoses radiator etc.... k would appreciate some feedback. Wondering if I should drain the system now that its done its job. Thank you
Toby Tookey
Feb 27,2019I decided to try k-seal after having symptoms of a head gasket problems i'm glad i did, the engine was using about approximately 1 litre of coolant per 60-80 miles and also the rocker cover was full of mayo ( mixed oil and coolant) The mayo is now beginning to clear away, the coolant leak has been very much reduced, now using roughly 150ml of coolant per 140 miles - much better, i'am unsure if the leak wasn't quite sealed the first time - hence i'm temped to try another bottle of K-seal to hopefully finish this leak for good. I would recommend k-seal, for the price it is a small price to pay and potently save big costs, the bottle its self is handy enough size to keep at hand just in case. Thank you for making this product, it was my first time at using a coolant stop leak product, and have been impressed so far.
Joshua Acosta
Feb 20,2019Thought this product was a joke, but its the real deal! Jeep liberty coolant leak in a unreachable area, used it just how the manual said on the bottle, literaly 5 minutes or less my leak stopped! Just an incredible feeling to see something work like it said it would. Its been 2 weeks plus, coolant still at same level! Id recommend this product to everyone and anyone! Gets the job done! Thank you KSEAL!!!
Martin Tromans
Feb 19,2019Great product and very helpful advice given from K-Seal
Rich T
Feb 18,2019Had a coolant weep on a 1995 Range Rover where the drain plug seals in the radiator. When pressurised the coolant was getting past the o-rings and a slight drip would appear around the drain plug. This was the plug with the wings that hand tightens. Trying to unscrew the plug it was extremely tight and I would flex the wings leading me to suspect it was glued in. Not wanting to break the end off leading to a new radiator I tried sealing with self amalgamating silicone tape but no luck. Prior to going down the permanent glue route, I was recommended I try k-seal. Worked first time. I guess it’s sealed the tiny gap between the hard plastic faces of the radiator and the drain plug. Radiator no longer weeps past the o-rings, and neither do I.
Thomas Vos
Feb 14,2019Best service I've received ever. The first bottle worked for a month so I got a replacement in a week! That is holding out for a few weeks now! So it looks like it saved me a few bucks on a head gasket replacement!
Brandon Boyd
Feb 14,2019Great stuff fixed my 04 Benz coolant leak instantly! Was wondering if it would seal my power steering leak?
Luis Garcia
Apr 23,2019Just used it on my car today after having a pretty bad leak works great so far. Saved me money for sure.