5.0 out of 5 stars Impressive

R. · June 2, 2025

(function() { P.when('cr-A', 'ready').execute(function(A) { if(typeof A.toggleExpanderAriaLabel === 'function') { A.toggleExpanderAriaLabel('review_text_read_more', 'Read more of this review', 'Read less of this review'); } }); })(); .review-text-read-more-expander:focus-visible { outline: 2px solid #2162a1; outline-offset: 2px; border-radius: 5px; } 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.

5.0 out of 5 stars Impressively Stopped Head Gasket Leak

R. · May 27, 2025

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.

1.0 out of 5 stars Does not fix every vehicle with a head gasket leak did not work for me. .

R. · February 13, 2025

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 .

3.0 out of 5 stars I guess it was a gamble because my problems is more serious

D.C.P. · May 18, 2025

It did not fix my problem. I guess it’s a real gamble.

4.0 out of 5 stars It worked for me at the moment

G. · March 30, 2025

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.

5.0 out of 5 stars Not going to lie, I did not really expect this to actually work.

S. · January 25, 2025

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.

5.0 out of 5 stars Worked on Chevy 5.7

L.B. · July 4, 2024

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.

5.0 out of 5 stars It works and is very easy to use.

P. · April 4, 2025

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.

Excellent

Z.V. · February 10, 2022

(function() { P.when('cr-A', 'ready').execute(function(A) { if(typeof A.toggleExpanderAriaLabel === 'function') { A.toggleExpanderAriaLabel('review_text_read_more', 'Read more of this review', 'Read less of this review'); } }); })(); .review-text-read-more-expander:focus-visible { outline: 2px solid #2162a1; outline-offset: 2px; border-radius: 5px; } Très bon produit. Très efficace.

Kein eingehender Test möglich, denn...

v. · June 24, 2019

das Zeug hat in nullkommanix das Thermostat abgedichtet. Immerhin...Ich glaube, dass so Zeug unter optimalen Bedingungen funktionieren kann, ich habe es sicherheitshalber bei einem alten Auto angewendet, bei dem der Wechsel der ZKD nicht wirtschaftlich gewesen wäre, also ohne wirtschaftliches Risiko.Dass das Thermostat allerdings sofort verstopft, hatte ich nicht erwartet, das dürfte der ZKD - und damit dem Auto - dann den Rest gegeben haben.Friede seiner Asche.Ich werde es nicht noch mal kaufen.

Funciono

J. · August 25, 2023

Usado en un coche de circuito al que se le exige el máximo constantemente en el que ya comenzaban a traspasarse los gases de los cilindros al circuito de refrigerante elevando la presión del mismo, tras aplicarlo según instrucciones del fabricante se resolvió el problema hasta tal punto que a día de hoy tras casi un año y varios eventos rodando a altas rpm sigue solucionado evitando destapar ls culata. Estoy impresionado por el resultado.

Worked as advertised.

B.O. · July 30, 2023

My review of the product application is as below.Car:BMW E36, 1995, 325, sedan, single vanos, M50 engine, Mishimotor expansion tank filled with BMW blue coolant. Location - Kuala Lumpur.Issue:Mild white smoking with slight coolant loss (about 50ml a week). Suspect coolant leaking from head gasket into combustion chamber. No signs of coolant to oil leak nor oil to coolant leak. Water temperature is stable.Application:Applied KSeal Ultimate 3 days ago into expansion tank (pumped out some coolant from expansion tank to fill kseal) and followed the instructions. Smoking stopped about 20 mins after engine was at operating temperature. No signs of overheating.Result:Since applying KSeal ultimate 3 days ago, drove a total 450km - mix of short distance, one long distance (120km) and in heavy traffic. Had done high rev driving up hill about 80km round trip) twice as well. No smoking to report and temperature was normal so far. Coolant levels checked in the morning and didn't seem to drop. So far so good, will update here if there's any issues. Very happy with the product.

Not helpful

G. · September 20, 2023

This product didn't work as mentioned in the item description and also did not fix the problem which it was supposed to do. It was total waste of time and money for me.