K-Seal Avis 

OMG K-Seal saved me a huge headache. My heater core was leaking in my 2005 jeep grand Cherokee. Getting to the H fast on my temperature gauge. Bought K-Seal dumped it in my coolant reservoir along with a gallon of 50/50 I lost and I literally watched my gauge go way down. Stopped all my leaks
My AC still blows snow. So didn't clog my lines or anything.

Unfortunately it didn’t work,tried head gasket repair,followed the instructions as to the bottle instructions,run to work 2 days later and ok,run to town which is 10 mile round trip got back home and top hose is solid and hot .It looks like a major head problem.

Good product. Worked on a previous car.
Recently had a garage put it in my car without warning me. Car is still working but didn't/doesn't have any warning signs of a head gasket. Garage then proceeded to forget to replace 1 lug nut per wheel after removing locking wheel-nuts. Bad garage.
Good product.

First of all. I believe in this product. I went online and read all the usage instructions. I think I have major problems with the head gasket and block after major overheating. This stuff has made it possible to at least get it running again. They don't claim to fix major problems. I followed all instructions to the letter, even advanced instructions. At least now I can run it for short distances. If it doesn't work for you, the damage is just to severe. I think that is my situation. They only claim to fix small leaks. Don't blame them if you don't do all the research.

Vw caravelle 2.5 Tdi
Was using water ( no other symptoms) applied k seal and it’s done the job has been good for a few hundred miles , gotta be honest k seal really does work. And has saved me around £1600 try it !!

Fallowed all directions. Warmed up to temp. Let pressure off, and put k seal in top reladaiotor hose. Now it is producing soap type bubbles and causing the engine to over heat again. Total waste of money and hopefully it doesn't cost me the whole engine.

My Mondeo 1.5 Ecoboost was leaking coolant and my garage concluded it was a the head gasket. I came across K seal online and having read many reviews and generally researched it it seemed worth trying. One treatment and bingo, the header tank level is not going down any more. I have done a few hundred miles now and all is still well, and I hope it will prove to be a permanent solution. I read that k seal can be left in the system, will it stay alive active if a new fault develops? If not could I add more in that situation, I would be interested to know.
This has potentially saved me a lot of money, I am keeping my fingers crossed. Thankyou k seal.

It did not seal my headgasket problem.

This did absolutely nothing for my head gasket waste of 25 bucks. The warranty is pretty much useless you want me to drive my vehicle to a mechanic with a blown head gasket so they can verify that it's leaking for $25 screw them and there's sht products

I hadn't had much luck with cars recently, my jaguar was hit and run in a car park and afterwards I had problem after problem, I bought another car which the head gasket went on the way home, a local mechanic took it to replace the engine which I'd paid for and still has it after 8 months, I bought another car to get me to work which developed brake issues, suspension issues and then started to overheat too... I had recently opened my own business so I had put all my savings into it so money for another car was an issue..... so I got car no 3 very good condition so I spent my last spare money on... it started to leak from the radiator and I was filling the water every couple of days...so I tried your product and I can safely say it worked very well and I've not had any more leak issues! I needed it to work as I couldn't afford any more garage bills or a new car.... so thank you your product saved my car and me lots of money I don't really have.

I'm sorry to say it did not work. The leak is small, I'm surprised. Can I get another bottle and try again. The leak is at the top of the radiator in the corner.

Used this product for a coolant leak. Not only didn't it fix the leak it gunked up my engine and timing chain to the point of major engine damage and repairs.

I have a 2002 Subaru Outback which blew its head gasket in November of 2023. My mechanic said the repair would be over 3000 dollars, which is frankly more than the car was worth, but said that if I didn't want to pay for the repair I could try a product like Blue Devil. After researching online I found K-Seal and decided to try it as a hail Mary to save my car. I picked up a bottle of K-Seal Ultimate and followed the instructions, and the engine stopped overheating almost immediately. It's been almost 18 months since that happened, and the car hasn't had any issues with its head gasket or coolant system ever since. The K-Seal repair has withstood daily use in a very hot climate, and allowed me to keep using the car which would have been totalled by the head gasket. It cost around 40 dollars for almost a year and a half of life added to the car, and it's some of the best money I've ever spent.

Tried Kseal numerous times with no luck. One bottle of
Blue Devil and problem solved.

Works great

Do not use K-Seal. It blocked up the heater matrix pipes in my car and the car overheated within a few minutes of starting up. Before that the car was driving fine but no heat coming from the heaters 30 mph and under. Only heat coming out at 50 mph and over. This is because the K-Seal was blocking the heater matrix pipes.

I had to have the car recovered and repaired at a garage. The garage confirmed it was the result of using K-Seal.

Yes the product will fix your car and stop leaks temporarily. However, in the long term it will damage your car and cause more problems.

K-Seal after a few months of being in the coolant system turns into a muddy/sandy type residue that blocks everything up in your car's cooling system. You have been warned.

I bought the small bottle of K seal as I was topping my radiator fluid every 2 weeks especially after a longish drive around 80 miles each way. I didn't expect too much. BUT IT WORKED GREAT. been in around 4 months no more topping up coolant. I wasn't losing coolant from radiator but I was losing it from somewhere give it a try nothing to lose ☺️

Excellent advice from Mike as I was unsure if KSeal would be compatible in a big 4L V8 performance vehicle. It worked!! An absolutely amazing outcome. So happy the big car is holding water now!!!

Very disappointed. Called them a week ago and they assured me they would get right back to me the following day with some kind of solution, understanding the dire urgency of my situation. No one called me back, so I had to just phone them again today, twice, and they are putting me off saying they will get back to me, again. Really? When?! Perhaps this honest review might get their attention. Used a half bottle of K Seal based on the recommendation of a mechanic as I could not afford a costly coolant repair, and it has ruined my car. My PSM failure light now comes on intermittently as well as the full time warning engine light being on, and my kids and I are now stranded here way out in the country where we live, an hour form the city. This is my only vehicle, and is now not drivable, and I cannot take myself to breast cancer treatments nor take my kids to swim practice, or even get to the grocery store. Thanks to this product, my situation has gone from bad to worse, and I hope they will take responsibility and pay to get my system thoroughly flushed out as I cannot afford to do so. I have since spoken to numerous mechanics as well as my local Porsche dealer and they said to never, ever use this product as it damages the system it is supposed to repair, resulting in sensor damage, clogging up the system, etc, etc...they actually warn people to never use this product and most say that they will not service any vehicle that has K Seal in it due to the numerous, mostly unfixable issues it causes to high performance cars. I am so distraught over this, I have lost sleep because I am in a dire situation without my vehicle and no money to cover what sounds like a costly and lengthy repair situation. And for history on the vehicle...I am the one and only owner of this vehicle and have maintained it perfectly for the past 18 years, and up until today it has never had any major issues. It only needed the occasional brakes, tires, oil changes, annual service, etc....so I know the complete history of my vehicle and have been the sole owner. It has been a faithful, reliable car without any major issues. And to make matters worse, the one woman who answered the phone today was aloof, dismissive, and unkind, saying there was nothing she can do about anything and I will just have to wait for them to get back to me. Seriously? RUDE!! Please K Seal, do the right thing and help me get my car flushed and drivable! How could you do this to an innocent customer?

Never let me down . Gone are the bad old days of radweld 40 yrs ago blocking pipes .
K-seal has been excellent for me and always carry a spare bottle.