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AnswerI used KW block seal 25 years ago on a Chevy 409-425 HP engine that had a crack running almost the whole length of the passenger side. Previous poor attempts at welding only chased the crack forward. I had acquired the complete engine at the time for 400 bucks and the only help I got was from a old timer mechanic who suggested the KW sealer. Following the directions I used 2 full cans and ran the engine for a full hour to assure a good seal. as i did this in the fall i was not worried about overheating the engine. The stuff did do as promised and the leak stopped. I ran the car daily for a full week before flushing the block and installing antifreeze. The car ran with this engine for 2 years without a leak. However, in the summer it always ran hot (210 to 230 degrees) and would on occasion would not turn over due to heat soak. Usually a hr cool down would then allow the motor to turn over and start. It was replaced with a 409 that I had reworked for more power. That was the only reason, not because it ran hot or might leak again!

Recently, I pulled this engine out from the back of the garage and did a tear down for possible reuse. I found that with the block seal a good portion of the waterjacket was filled in the area of the crack and was most likely the cause of the hot running in the summertime. Since these blocks bare are going for over a grand on EBAY (even cracked!) I have looked into getting it repaired by welding the proper way and having the waterjacket cleaned out. it is too valuable to be junked.

AnswerUsed it on Saturn sl1 that had either a cracked head or blown gasket to the point where it needed anti-freeze every few days(it has 170,000 miles on it, so a $1,000 or $2,000 repair was out of the question). Drained the radiator, flushed it, then filled with K&W and water for 300 miles. Then drained, flushed, and filled with the normal 50/50 anti-freeze water. Totally cured the problem and I've gone 2500 miles/3 months with it so far. I notice that if I'm stuck in traffic on a hot day the engine temperature creeps up a little, but still below the halfway mark, and far below the red zone. AnswerI used K&W Nanotechnology block sealer (green bottle not the can), and it worked as described. I am speaking from personal experience, I DID use K&W and it DID work. If you are considering this be absolutely sure that you drain ALL coolant/antifreeze. The directions say drain, flush, and repeat. If in doubt repeat as many times as necessary until you are comfortable that it has been done properly. Let me say that one more time FLUSH FLUSH FLUSH AND FLUSH AGAIN! Depending on how bad your specific situation is, leave the mixture of water and K&W in for a couple days and drive normally. However after the inital idle period of 30min do allow the 12hr dry/curing process to take place. Then before you refill with coolant/antifreeze drain, but do not flush, allow to dry/cure, flush flush flush and flush again, Then refill with coolant/antifreeze. This product does work if done properly. People who have had negative experiences most likely did not follow directions correctly. This $20 bottle is definitely worth a shot before spending the $1000+ to take it to a shop. I hope this helps anyone who is looking for actual experience with this. I did a lot of research and most of it was skeptics and opinions. Take the time, do it right and follow directions and i think you will be happy with the results. AnswerI wanted t add my experience. I have a 1996 BMW 328iC and they are sensitive to heat. Well, I had a water pump go out and it ran REAL HOT.. I started noticing coolant going low, but none in the oil. The car ran hot a couple more times for various reasons that were my fault. Well.. It started white smokng BAD, burning LOTS of coolant. The good part is that I never noticed water in the oil and it never overheated as long as as there was coolant in it. I priced what a new head gasket would cost me to get replaced and I almost fainted. I had heard of these sealants, but never used one. A friend's buddy had an old explorer with a bad head gasket, but it would overheat even with coolant full. He tried the type you just add to the coolant and go (add to anti freeze and all).. Well that was a waste of $30 for him because it didn't fix it and the truck was worth far less than the repair bill would of been. I felt I had nothing to loose by trying a sealant and I went to Walmart and bought a 16oz can of the K&W head gasket sealant for 7.99 plus tax.. It was the type that was not antifreeze friendly. I flushed my cooling system prob 10 times to get ALL of the antifreeze out (any antifreeze will cause it not to bond to the head gasket). I then added the contents of the can to about 2-3 quarts of hot tap water and added it to the car. I then started the car and ran the heater on full blast (not doing this will cause it to seat up heater core, and cause even more problems). I topped off the coolant system and let it idle for about and hour. I then drove the car around town for another hour at low speed/rpm. I never went over 2000rpm. I took it home and drained the entire system and left all drain plugs and caps off off cooling system (says to let the open system dry for 24 hrs before starting again. Well, I waited almost 20 hrs and added straight water to it after replacing drain plug and then topped it all of, put on the cap and drove it for about 4 hrs around town. I still didn't drive it hard but took it on interstate and drove 80mph. Not a single bit of coolant smoke came out of my exhaust at all the whole time. I took the car home and drained it, added water, let idle 20mins the drained again I repeated that procedure about 10 more times until pure clear water was draining each time. I then fully filled the cooling system a mixture of antifreeze/water and drove it another 2 hrs with NO PROBLEMS. That's was last night. So it seems to have worked. AND FOR ONLY 7.99 plus 10.00 worth of antifreeze! That sure beats $3000 to replace the head gasket.. I've been told this could last for a few months to a few years.. 'm just gonna drive it easy until I can find a good mechanic to do the job on the side for some extra income after I can save up the "repair fund".. But so far this stuff seems like a miracle. $20 w/ anti freeze? I also changed my oil and filter in case a little water got in the oil. KW Head Gasket Sealant.. Sold at Walmart and most auto supply stores.. There are two "grades", this 16oz 7.99 and then a $20 + grade that says it "dries" in half the time and is in a bigger bottle and had a money back guarantee.. IF you do it correctly.. Seriously.. FLUSH OUT THE COOLING SYSTEM before you use this. If you think you've flushed it more than enough times, the flush once again. Make sure the liquid draining is CLEAR.. I think that is the key to this stuff working. Also remember, some head gaskets will be too far gone to use something like this to fix it. But if you catch the problem fast then immediately do the treatment, then your chances are good of it working. Now time will only tell how good a job it did on my car. If it holds up, then this stuff is a godsend. Answer

Bar's head gasket repair is a problem product, Bar's posted everywhere super magic results when using the products, but none of this is true. Bar's uses trained resellers and people reselling junk cars to demote and discredit reviews posted by unsatisfied Bar's product customers and Bar's head gasket fix that reported the product didn't accomplish anything, but only trouble and engine damages.

Bars' charlatans keep working hard to keep alive a business that is sinking and the product is a problem when used in today's aluminum heads. Aluminum heads were designed and still manufactured to get hotter engine, burn better the gasoline and get higher gas mileage. On new cars, the factory head gasket last longer and is flexible to adapt to the aluminum physical expansion of 33%, but at one time, it will break and the coolant to refrigerate the engine will start leaking. Bar's products, under engine temperature, will became hard as a rock, but the sodium silicate (glass) will break and the leak will come again and again.

It worked on very old iron heads and block, but is not longer in use for the last 25 years or more. Today Bar's head gasket is a myths, keeps alive by owners that refused to look for a job, but instead, they keep pushing a bad product to rip off people.

I think, Bar's copied some products formula from other company, by sending the original product to a chemical laboratory to find out the chemical composition, modified the original formula by adding a different color and stuff.

A company or business, when successful, will show the chemical laboratory in use, very large testing areas testing all kind of engine, technicians and engineers working on it and everything of its technical know how. Also, prosperous owners will always have and drive very expensive cars and live in a very expensive residence and the business will be located in a very well known business park.


Robert J Mermuys and Fred Mannix, owners of Bar's Product built a sand castle in the internet, built on photos and illusion posted on its websites, to show a business image that doesn't belong to them. Bar's business is in a cheap location, full of coyotes, but no people around.

Ridiculous reports posted in the Internet of Bar's that sold 25 million dollars in 2011 and in 2012 reported that sold 50 million dollars in bottles of its products (all big lies).

Bar's prints on it bottles: "Most trusted stop leak since 1947," but in different websites, Bar's said that the company was created in 1929, and 1921 in another one.

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Q: Has anyone used KW block and gasket sealer did it work?
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When replaced the thermostat on a 1997 1.8 2WD Sidekick sport it leaks on the bottom screw of the housing if a thermostat sealer was used and it didn't work?

Two things I'd suspect are: First thing I'd suspect is that you missed a portion of the old gasket. These gaskets are some of the harder ones to remove as they are usually put on dry and actually penetrate into the pores of the metal(s). If you're not sure take the housing off and check to see if there's any old pieces of gasket left. If so, remove them with a good gasket scraper (I like the decal removers for this), pocket knife or sharpened putty knife. If you're sure the surfaces were clean then there are cautions if you used a gasket sealer. The gasket cements and solvent based sealers usually don't leak, silicones will if not installed properly. When using silicone sealers you have to let the sealer dry at least until it's almost completely set, if you don't the sealer can act like a lubricant and let the gasket slide which can cause a leak. I usually spread a thin coat on gasket, stick it to one of the metal surfaces and spread a thin coat on the other side of gasket. When the silicone is completely set I then install and the silicone will penetrate the pores of the metal which makes the gasket easier to remove.