K-Seal ST3501 Pour & Go Head Gasket Sealer, 16 oz – Repairs Blown Head Gaskets, Cracked Heads & Engine Blocks

I have a 2012 Toyota Prius type v they're generation known to have head gasket issues over time. Well my time had come last winter Winter of 2024 and I was deciding whether to put new engine in it though I did not have the money and I called a repair shop in town called engine and transmission exchange and told him I dilemma. Well to my surprise The gentleman behind a counter felt my problem and told me try this he had a guy who delivered parts who had a old Chevy van that had the same head gasket issue. He gave it a shot because one of his mechanics told me to try it what's the worst that could happen. By God it worked that man has been driving that same vehicle for 5 years now so I gave it a shot. It's a year later I've had no head gasket issues whatsoever no overheating no loss of fluids since that time I put it in. Heck of a lot cheaper than the engine. A $23 bill is a heck of a lot cheaper than a 5 to $6,000 engine replacement.

Followed instructions on how to use and it did not work, BUT they issued a full refund I'm a pretty timely manner.

It took about two weeks but it finally sealed the Head Gasket on my daughters 1998 3.8 liter Mustang. It did not damage the heater core or thermostat. I kept in contact with the manufacturer on the proper way to repair this head gasket. I was also told that I can flush the cooling system if I so choose and that it would not affect the repair. Money well spent!

Better than other stuff in this same brand. Helped but didn’t fix. Start tearing down engine 6.6LLY

I’ve used this product in one of my older cars and it works, I believe you get what you pay for and this is worth it

This stuff really works. First try . Thanks .

Didn’t work in my situation

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.

Trovavo olio nella vaschetta del raffreddamento. Con k-seal ho risolto

Très bon produit. Très efficace.

Iba a llevar mi coche al desguace y gracias a este producto funciona perfectamente, ideal para roturas de junta de culata leves

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.

Bit of my background. I'm an ex-Honda technician of 24 years. But I quit the dealership over 10 years ago. I feel I'm quite experienced with cars. Honda's at least.I still drive a 1996 Honda Odyssey, here in Aug 2025. Beginning of this year, I noticed a mysterious coolant loss. Maybe a 1/4 liter every 2 -3 weeks. Also some intermittent stumbling or misfiring when engine is started, but clears up within 2-3 seconds of starting. Also noticing excessive pressure being relieved when opening the rad cap. Typical head gasket symptoms. Then I noticed a few drops of coolant on the ground. That ended up only being a leaky radiator. Found a cheap new radiator on Rockauto and replaced it, hoping that fixes all coolant loss issues. No luck. I continue to just drive it and topping up coolant. July comes around and the misfiring after start up is getting worse. At times, taking up to 20-25 seconds to clear up, and now it feels like it's multiple cylinders misfiring. The new radiator is leaking as well. I assume the excessive pressure from exhaust in coolant is the cause. Given the van's age, 500,000 km's and host of other issues it's had in the past year or 2, it's not worth the time and energy to fix a head gasket. I fear this is the end of the van. My wife is thrilled and ecstatic, she really wants a new or newer vehicle.I've never been one to believe in any of this "quick fix in a can". But at this point, its worth a shot as there's nothing left to lose. Bought a bottle of this K-Seal Head Gasket repair here on Amazon.Just after driving the van, the engine is hot. I opened the rad cap slowly and noticed the coolant was low. I didn't bother draining any more coolant as I hoped it was low enough to fit the whole bottle. I was wrong, only managed to pour in just over half the bottle. I started up the engine and ran for 40 mins. Shut off and cooled for 3 hours. Reached under the radiator and opened the drain just enough to pour in the remainder of the bottle. Started engine, no misfiring. Perhaps just a coincidence. Ran for another 40 mins then shut off for the night. Next morning, I started it up, still no misfiring or stumbling. Drove to work just fine. started up after work, again no stumbling. It's now been a week and a half of regular driving and I finally checked the coolant level. It was full, no top up needed. New radiator stopped leaking too. Still early, but so far the results are extremely positive. I'm thrilled and ecstatic. Wife is not. I will update if it shows signs of leakage again