Hell yea it works... Im not just saying that because I work for K&W, it really works. Busset my damn gasket on the freeway yessuhday.. put in the potion and now my truck is purrin like a cat... great product

My experience with CRC Industries, who manufactures K&W Block Seal, has not been good. They are anything but a customer-friendly company, even after I told them I was not contacting them to file a claim. I used their silicone spray, which ended up melting the item I used it on. It turns out CRC adds acetone to their silicone spray, which is a powerful solvent. When I called CRC, they adamantly defended adding acetone to their product, claiming that everybody else adds it too. I checked several other products on the market and checked with their manufacturers. I did not find anyone else who added acetone to their silicone spray. I notified them of my findings, but they could have cared less. Because of my experience, I would not use any product made by CRC--I don't trust them. If CRC can't even make a safe silicone spray, why should I trust an engine to Block Seal?

I'm skeptical of all of these products! People come on this site claiming stop leak products work--most of whom work for the manufacturer. All I've ever seen is the mess created afterwards--residue formed around the thermostat, radiator cap, and a token layer of crud around some parts of the head gasket (not enough to seal anything). My opinion is to fix it right or leave it alone. These products prey on the poor and desperate.

Just urinate in the radiator and the metabolites will fix it just fine. (If it's the head gasket) The metabolites bond with the mead "gasket matreial".. The urine actually turns to a glue that will seal up the head gasket whe it reaches a high enough temp. Only use this method if you live in South Africa and have no access to the K&W sealant. The urine will last only a few months.

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Napa has the K&W line which is produced by CRC industries

Walmart sells K&w block seal.. its an orange and silver can. I just bought some as I have been hearing good things about it and my minivan that I just bought has a head gasket or intake gasket leak. Hoping that it works. I believe I read that Napa also carries it, but don't quote me on it.

Blue Devil seems to have worked for a lot of folks and there is a YouTube video of it being used.
It takes about an hour and a half to "run in" the system then has to sit and cool overnight.
Look on YouTube under head gasket sealant. It is between 35.00 and 60.00 US and some places online
Ship for free. Good luck. p.s. make sure you change your oil soon afterward just to be on the safe
Side, it can't hurt.

My daughter ran her car low on coolant, and warpped one of the heads. Now combustion chamber gases are getting into the coolant and the exhaust is blowing white smoke. Will this product fix this?

John24255, not likely.

CRC makes some good electrical contact cleaner works very well, but I use brake clean (any brand) and it seems to work just as well at a fraction of the cost. I have never tried their KW block seal, I would take the advice of TxGReaseMonkey as He/She had done the research on the products and has a solid reputation and would not lead you wrong. The key is,know the product and its alternatives. You tend to get what you pay for. Remember you never really know what the extent of the damage is until you look inside. Any chemical is a gamble. It may be a money saver or a total waste of cash, but if you don't have the money for a major repair, it may be worthwhile to try a product. If you use urine as dawn278apt162 suggests and it fails, no one will want to work on your engine and smell burned urine. I would only try that if I were stuck 200 miles in the back woods with an off road vehicle, to be followed by a complete flush of the system.

I used a drain and rinse block sealer about 4 years ago after a guy I raced with tried it on a $20,000.00 + race engine and it worked fine and lasted until the end of the season, about 20 full nights of racing, at which time the engine was overhauled as it was in the 1300 lap rebuild range but ran perfect. I put it in my 240,000 mile 305 Caprice because it had a leaking head gasket and figured what did I have to lose. I drive over 55,000 miles a year as a salesman and after 140,000 miles I sold the car still running fine 380,000 to a kid at the A&W for $500.00. 2 weeks a long time friend and mechanic was *****in about having to fix the leaking headgasket in his 2000 Chevy pick up, 140,000 miles, I told him to try the block sealer. He did it and then for his current job he drives 200 miles a day for the last week and lost NO coolent. Yup it works and I am beginning to think there are many of the flush out the coolent types that work well. As a racer and engine builder I look at this as a first step BEFORE you tear an engine down.

Some head gasket sealers do work. But only under certain conditions. Read this

When to use a head gasket sealer and which ones work?

Hi there I got a bmw 2002 735i v8 I thank I got a blown headgasket what do think if I use K&N block seal is it going to effect the water pump because its electric water pump can you pleas find out information about that.

Hi all, my wife has a 1993 Holden Barina ( a re-badged suzuki swift). There was water in the oil and oil in the water evident by emulsions on both caps and a bit on the oil dipstick. I drained the radiator, flushed the radiator twice and then added water to the radiator. I added a 250mL bottle of Cargo Metallic seal-up. Claims to permanently seal cracks/leaks at every interface, head, gaskets, water pump, radiator etc. I immediately took it for a 45 min drive. It's the second day and the sealer is still in the radiator. I plan to leave it in there for another few days (over kill) where I will then drain, flush and add coolant. It works! It worked after the first day. No more emulsions in either the oil or the radiator. Water in overflow radiator reservoir is also stable. All for the low price of $12. Like other posts, I am confident the Barina has now got another 50K to 100K kilometres in her. I highly recommend it! I know this post is 12 months after the last but I wanted to get my good news story out there.

My 1998 linclon town car ran hot. I checked the oil and it was very very low. I added more oil and a stop leak. After this the car drive OK for about a week. Then it ran hot again. This time the oil level was OK. I looked into the radiator and there was no water. When I added more water it leaked from the botttom of the engine. I do not have the money to fix a blown head gasket or cracked block. What is the best block sealer to use? One that will not clog up my heater core.

Nate