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

Have a 2004 Ford Escape with about 200,000 miles. Started getting a check engine light; misfire on #1 at startup and very rough idling every time I started the (cold) engine in the morning until it warmed up. Tried the usual; plugs and ignition coils but no help. Noticed I was using water but no sign of a leak. Finally suspected that I had a blown head gasket around #1 cylinder. Read good reviews about K-Seal so thought I'd give it a try and poured a 16oz bottle in. Drove it around for about 20 miles then parked it till next morning. Started it up and no check engine light and the idling was much improved (but not great)! I left the K-seal in and now, about 3 weeks later, have not had a check engine light again and the idling has improved steadily until I can say it is now very smooth at startup and when stopped in traffic. I think by leaving the K-Seal in that the gasket leak has steadily improved and so has the engine performance. Thank you K-Seal!

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.

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.

Did not work for me at all. May or may not work depending on your vehicle.

It works well. However, I think it affects on the radiator thermostat negatively.

After fixing all of the external coolant leaks, I was still having to refill my overflow tank every three days. After adding your product, within a week the level of coolant stopped dropping and now there is no need to add coolant. It has been over 3 weeks since changing my oil which, was the same time I added the head gasket sealer. For 3 years I have added both coolant and oil on a weekly basis to a truck that drives 100 miles a day, that is every day, I no longer have to add any oil or coolant. I am so impressed with these results, I wanted others to know. Thank you so much for probably adding thousands of miles to the life of my truck. I thought I needed to replace the motor prior to adding your product. Now I don’t worry about it. Thank you.

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.

2013 Ford F150 4X4. I had a small head gasket leak. Followed directions to a T. Within 3 minutes after a full warm up of the engine, my leaked stopped. I drove it about 15 miles, brought back home. Let completely cool down. Drove again next day, still no leak. I am very happy with this product's results. I highly recommend this over Blue Devil.