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 bought this just a few days ago because my 2005 Hyundai Elantra was over heating and cooling within a couple miles of driving. The temp gauge would spike to the top and then slowly go back down to the middle mark. The Heater would blow cold air, then a couple mins of hot air then go cold again. I had to replace fluids every time I needed to drive anywhere and just before I used this product I found moisture droplets and milky residue on the oil stick. The thing that sucked is that all this happened right after I had the valve cover gasket replaced, the radiator replaced because we found a large hole near the cap area, had an oil change, replaced all the spark plugs and wires (actually, I had to replace them a 2nd time because the were being destroyed by the over heating issue) and repaired the exhaust and catalytic converter (even after the CC repair I was burning though gas and having some misfiring issues. which is why I had to change the spark plugs a 2nd time just before I tried K&W). So needless to say I did a lot of work on this car (A COUPLE WEEKS) before I realized there was an issue with the head/cooling system. This is my only car and I rely on it to get to my college classes and take care of my kid. I'm a single mom, thankfully with a bit of mechanical knowledge.So, I read all the reviews....good and bad. And I noticed a trend. All the good reviews said they followed the directions explicitly. So that's what I did. First, I hadn't driven my car in 2 days. I borrowed my mom's car for those 2 days just so I knew it was a 100% cold engine. Then, although I was reluctant about adding it directly to the brand new radiator I just bought (a month ago) I had to, because I couldn't get the top hose off. So, I added 1/3 of the bottle to the radiator and then added some distilled water to it as well. Because, I had read from some of the other reviews that coolant and this product do not mix well. If i need to add more coolant later I will. For now I just used enough distilled water to top off the fluids. I also added distilled water to my reserve tank. ALSO NOTE, the instructions say to start the car and leave it running on idle while SLOWLY ADDING the CORRECT amount of K&W. After SLOWLY ADDING it to my idling engine, I let it continue to run on idle, I turned the heater on FULL BLAST for 30 mins and I sat in the car watching the temp gauge, it did creep up to quarter mark but didn't get to the half mark, which was a great sign!I'll try to add to this review over time. As I just used it today, so only time will tell if it truly works. But I am keeping a positive mindset. I need this to last at least until taxes, then I can think about a "newer" car.I hope this review helps someone else.*Update:Almost 2 months later and my car is still holding up! (Dec. 19, 2019)

I would only recommend this product if you are facing a cost prohibitive repair (head gasket).I had a slight leak out of a joint by the thermostat housing. I had to add coolant only a couple times per year. I did a bunch of repairs to my vehicle so I thought I would go for perfect and stop this little leak before it became a big leak. Hello FiberLock, goodbye $955!After carefully following the directions and using the product, my vehicle immediately started to overheat. This should have been clear to happen as the product is clumpy/gunky. I should have just stopped when I saw that junk come out.I paid for two cooling system flushes ($280) that didn't fix it; one thermostat swap ($200) that didn't fix it and finally one new radiator with pressure flush ($475) that seems to have fixed it.I cannot imagine your radiator would not get clogged up. If you use this product, you should expect to pay for a new radiator and pressure flush. What a stupid, costly mistake it was to use this product to solve anything other than a head gasket leak. The bottle says it permanently fixes "cooling systems" so trusted it. Don't be stupid like me.

K&W FiberLock Head Gasket & Block Repair, 32 Fl OzInstalled as repair for over a week now, Zero, coolant loss. after 3 days. Kept having to add before then but that may have been mostly air in the system as this Rendezvous is notorious for air pockets.I put into the return hose on the back side of the thermostat, I think this is where most have issues, used 1/3rd of product, engine heats up, hot water moves across product and into the system, wholla.... head gasket visible leak was done in about 15 minutes, I ran it up to operating temp then started my 15 per directions.Internal leak and radiator took a couple more days.