K-Seal ST3501 Pour and Go Head Gasket Sealer, 16oz, Permanent Repair for Blown Head Gaskets, Cracked Heads and Blocks

Jeep Wrangler 4.0 Inline 6. Had an issue with a piston and suffered a catastrophic failure. Disassembled engine, and replaced piston, then reassembled with a fresh head gasket. Did not plane block or head, just put it back together. Engine ran fine, but I noticed lack of coolant system pressurizing, and I was refilling the radiator daily. I found a pressure leak near number 1 cylinder, which was causing significant coolant loss when engine was operating. My head was either damaged or I nicked the gasket when putting it back together by myself. Which is possible, that head is heavy and awkward. Anyway, after a lot of reviews and research, I selected K-seal. I followed instructions and added it directly to radiator. It has small copper looking flakes in it, and at first I thought it was a waste of time, because after pouring it in, and going for a drive I saw the same small flakes on the inner fender where the steam from the leak was coming from. Then after a few more days, I noticed that my cooling system was fully pressurized when hot, and the coolant was not disappearing every day. It has been about three weeks and several hundred miles, and it is solid as a rock. No coolant leak, smell or refill needed. Very impressed, this really worked.

Had bad coolant blowing out the exhaust on my 1989 Chevy 5.7 K1500 111k miles. Not just steam but coolant as well. Used K Seal and it did not work. So pulled heads sent to machine shop that checked them and said no faults found. Heads milled, inspected cylinders, nothing found. In fact old cylinder head gaskets and intake gaskets were okay. Re-assembly did not touch the exhaust. Just as bad. I again used K Seal. Forget the 3-5 minute idle, did not work. So allowed it to cold soak overnight. Next day ran it on the road with it blowing steam all the way. Let it cold soak overnight. Next day leak was gone. Went for drive and no smoke. Mind you this was just day one, but given the severity of the leak, this looks promising. Still not sure why it worked on the second can and not the first. I lost a lot of coolant when I pulled the heads, but it is possible enough residue of the first can of K Seal remained.My current thinking is that the problem may be a crack in the intake manifold and not the block. This is because the engine did not blow coolant before I changed the intake manifold gaskets a few weeks prior just as routine maintenance. The manifold EGR passage was totally clogged with carbon which I removed. It is possible this carbon may have sealed the crack in the manifold. Chevy manifolds have massive exhaust and coolant passages that run parallel to each other and a defective EGR system could generate excessive heat that cracks the manifold internally. This would allow coolant to get into the exhaust.

Did not work for me after trying 2 bottles at 2 different times first bottle sealed everything up almost immediately and lasted maybe 3 days at the most added 2nd bottle sealed everything up truck sat overnight the next morning drove the truck about 30 miles and it worked fine. I let the truck sit for about 3 hours started up and the head gasket started leaking again . It won't seal every head gasket leak and if it does seal a heat gasket leak you don't know how long it will last .

It finally worked, but it took four bottles. You need to find the bad cylinder, then pull that plug wire. I let it run for an hour with the plug wire off.As of Dec 3 2024 It's leaking again. Guess it wasn't permanent.

My honda k20 had been burning off coolant. I couldn't find anything suspicious except for a smoking exhaust. I decided to add this in, and while the result wasn't instant, I did not have to refill the coolant again other than a small top off to normal levels. No more blowing smoke, and have been driving fine for several months. I am still on the side of caution driving only local roads. I haven't worked up to driving more than 50 miles on a single trip yet.

I had a pretty bad head gasket leak. I used the bottle and it sealed it probably about 75% better than prior. I got ahold of customer service and filled out the lifetime guarantee paper and emailed it to them. I explained that it was alot better but not all the way fixed. I asked if they could send me a replacement bottle to see if a little more would do the trick. 3 days later at no cost to me another bottled arrived. I put the second bottle in and within a hour no leak. A+ company that stands behind their guarantee of a wonderful product.

My 2012 Ford Focus was losing a pint of coolant per week with no external leaks. The small bubbles in the overflow tank indicated a head gasket leak into a combustion chamber. One bottle of K Seal Ultimate added to the overflow tank fixed the leak after 50 miles of driving. This stuff actually works! But watch out. The label states it is not for hose leaks, oil to coolant or coolant to oil leaks.

Purchased and used several times - different engines.Has performed as advertised / expected (successfully sealing) each time.Strongly recommend. (Shop when price reduced for extra savings. Keep on hand)