K&W 401224 FiberLock Head Gasket & Block Repair - 32 Fl Oz

used this to fix a hairline crack somewhere in the block or timing cover.so i have a 2010 jeep grand cherokee with a 5.7 hemi motor, bought it real cheap due to haveing a head gasket issue due to an overheat , im a tech for 40 years and know these hemi's well ,i did all the work myself , replaced both head gasket heads were sent out and resurfaced and i did a valve job , the motor fired right up and ran perfect when finished , however i noticed my coolant level was dropping slowley with know external leaks , after investigating i found coolant in my catch can so know i knew that it was getting into the crankcase, after i drained out about 8 0z of oil from the sump i saw a little bit of coolant in there but not to bad and not a lot . the coolant seemed to be entering the crankcase but more as a vapor if anything because most was in my catch can. there was a hairline crack somewhere . i decided to try this but was very skeptical . and low and behold it worked ! i couldn't believe it , no more coolant in my catch can or in the bottom of oil sump , i was amazed it actually worked , its been a year now with about 7k miles and still holding up! no coolant loss ,no heater core or radiator issues, i did put a new thermostat in it after about 100 miles running on it and found some hardened material around it but i wasn't worried about it after i installed a new one . i recommend this if you have a small leak due to a crack .

I have a suspicion that the bad reviews of this product are coming from people who are using it incorrectly. I had a blown head gasket (confirmed by repair shop when they replaced my timing belt, water pump, and thermostat) on a 1995 1.5L Honda Civic engine. The only reason I picked up a bottle of this sealant was because the mechanic recommended it after I told him that I couldn't afford a $500 dollar repair bill for replacing the head gasket. The mechanic told me that he'd used this stuff before and that it was pretty much the only head gasket sealant on the market that he'd ever seen work and told me that he would never recommend any other but this stuff actually works. So I ordered a bottle and gave it a try. The first thing I noticed was that the instructions clearly state that you should read the entire label before starting and that you should know exactly how much fluid your radiator and engine block hold and to use a specific amount based on the volume. It also clearly states that if your water pump or thermostat are not properly working that it will not work properly and could cause uneven distribution of the product. It states clearly on the label to use the proper amount and to add it very slowly into the properly diluted radiator fluid and not to add the product until the fluid level is high enough not to touch the fins on the inside of the radiator. After doing just that, letting the engine run and the coolant cycle and then topping it off, and then letting it idle for over 15 minutes with the heat on, I could already tell that the engine was running as smoothly as it did before the blown gasket. After several days of driving, it no longer overheats, no longer produces white smoke from the coolant leaking through the gasket into the engine, no long is leaking oil into the coolant and is no longer running rough. The stuff is very clumpy and can look worrying but when the proper amount (for me 1/3 a bottle) is added to properly mixed 50/50 fluid, it cycles through and smooths out. I plan on letting it stay in the engine until I get ready to flush the radiator out and get the rest off the product out but the bottle clearly states that you can leave it in without flushing and that it will not cause clogging or sludge. So far it has work perfectly and seems to have sealed the gasket completely but even if it does begin to leak slightly, it says that you can add more which I plan to do if it does, though so far it after 4 days of daily commuting for 36 miles, it has had no problems and works perfectly. I'd recommend it to anyone who can properly follow instructions but I would imagine that if you added it to the wrong coolant type or mixture or if you added way more than was intended that it would cause major problems with clogging up your system. Having a new water pump probably also helps, as I would imagine that if your water pump wasn't properly cycling the stuff that it would clog up in the system and prevent the sealant from reaching the leaking points and possibly clog up the radiator or heater coils. Use it as intended and it should turn out just fine.

I have a 2014 F 150 Truck, worked great in winter with hot air blowing strong...>NOT NOW after using this product to fix a leak on a hose. The leak is fixed but my next step is to pay a ton to change my radiator. My best friend is an attorney....I'm going to consider starting a class action and I can assure you there are many out there with the same sad results as I have experienced.

great produce but you have to know what your doing, this isnt for the average consumer, Poured it in the radiator hose and ran the engine as instructed, next day and on after, i lost heat in my heatercore, it clogged the smaller pipes and thermostate, had the flush out the whole system and unclog all the pipes with air, but the product seemed to have fixed the coolant loss issue.