To leave a review you need to be logged in
If you use ULTIMATE for a Head Gasket repair and it and it fails to fix the leak get in touch to find out about our money back guarantee. For all our other brands if you have a repair that subsequently fails contact us for a replacement bottle.
Reviews 493
Dave Blackwell
Nov 13,2018I have a BMW 525i E39 2001 that WAS over pressuring the expansion tank & cooling system, via a leaking head gasket. I was quoted in the region of 2k to replace the engine or similar cost to do the work to replace the gasket. Whilst waiting for an engine to be sourced, I did a bit of research and found this product. So bought it, as I thought why not, the engine is being binned anyway.. Added the mix as per the instructions and did my commute. 200 miles later, checked the level and it was spot on, and no white marks from over pressure in the expansion tank! It worked as described. Superb product that has saved me a fortune in the short term at least, and hopefully means I can get a lot more miles out of the car. Edit - I contacted the guys at K Seal first to ask about it - and they we're very helpful indeed. Thanks!
Yoyo Mathis
Nov 08,2018This stuff really,really works..I had a leak in my van didn't know where it was coming from..poured this in..30 mins later..no more leak...I highly recommend this product..this sh!t is amazing...
John McKinnon
Oct 15,2018This last summer tuna season I had a hydraulic lock on my Perkins Diesel engine that resulted in a bad coolant leak. Probable cause cause was a blown head gasket but it could have been a cracked head. I was 100 miles offshore but I was able to limp into the Columbia river for repairs. Considering the age of the engine I feared that a new engine might be my best option but that wold have ended my season. A friend suggested K-Seal and I was skeptical but nothing to lose so I gave it a shot. I was amazed. The leak stopped within a few minutes and after 600 hours I still haven’t lost any coolant. With 40 years experience as a marine engineer I wouldn’t have thought that possible but it worked for me.
Ken Spoor
Oct 10,2018I recently had a coolant leak in my Porsche 928, it was leaking from an o-ring in the thermostat housing, simple enough to change on a basic car, but the Porsche 928 is a lot more involved with regards to accessing it.., and I mentioned this to the garage that looks after it for me, he suggested trying K-Seal I thought might as well, nothing to loose. So following instructions to the letter I poured the K-seal into the expansion tank after syphoning the same amount of coolant out, ran the car up to temperature let it stand and then examined the area in the V of the engine where coolant had previously been pooling, absolutely no coolant leak whatsoever, I was amazed, and in recent days I have drained all my coolant to put new anti freeze in the system, I was a little worried that by draining the system the leak would return, but no, it was completely dry again. I can only speak of my experience, and from that,. K-Seal is very good at what it does, and would have no hesitation using it again !
Phil Smith
Oct 10,20182005 VW T5 with serious coolant loss from rear of block close to thermostat housing (suspected crack but unable to properly inspect). Coolant running down rear of engine as soon as thermostat opened. Losing about 1 litre per 10mins of thermostat opening! Poured K-seal into empty expansion (header) tank when engine was cold, topped up with a small amount of regular coolant. Drove vehicle until thermostat opened, drove another 3-4 mins, pulled over to check for leak from below. Nothing! The leak appears to be sealed. Excellent result for the meantime. Obviously the crack could get worse and the leak may return but very happy so far since I can't afford a replacement engine so hoping this is permanent as it says. I have left K-seal in coolant for the time being to hopefully continue to work if crack enlarges. Update, Had this diagnosed as most likely a head gasket. K-seal worked for a time and then failed as gasket leak worsened over time. Also tried Steel Seal and this failed also. I guess depending on how bad the gasket is and the type of failure these products will only effect a temporary repair. handy to keep you on the road whilst you consider your options!!
Darren Smith
Sep 08,2018No it didn't work and I suppose I didn't really believe it would but the great selling point is the price compared to treatment that will cure the problem correctly. The problem is pressure building up from the gases getting into coolant system due to a defective gasket. For k seal guarantee to be in place you must provide either breakdown evidence or garage evidence of the diagnosis. When I had my car diagnosed the garage carried out tests in front of me but unfortunately I never had the written proof as my eyes were evidence. I hear that this product in some instances works but given the pressure involved in combustion engine it was hard to see a liquid curing it. Colin I appreciate your feedback but one thing I thought is that you act like I am being retrospective but that's how I am literally finding your response. Maybe it would be more beneficial for the general public to speak to a k seal representative first before purchasing the product. Surely that way,considering the vast array of alternative treatments, k seal would always be 5 stars!
Phil Brewis
Sep 07,2018Have just used K seal in my 2005 Merc c180 , couldn’t get more than 10 miles without topping up coolant, within minutes it had solved my problem, this stuff is brilliant, not a drop , fantastic guys excellent product.
Dean Burton
Sep 05,2018Hi. Ok k-seal well I had @least 8 garages look @ our car as white smoke/steam was coming out of the exhaust pipe NO ONE new what it was a garage told me about k-seal and said he would charge me £50 to put it in for me as a last hope solution to fix the problem. I then went home YouTube k-seal watched the videos about it then used it expecting nothing as we all do then guess what ??? My car runs like a dream but can't believe it I really can't this product works 100% it has saved us 100sssss thank you k-seal
Brendan Perring
Aug 27,2018K Seal Ultimate works : So after a year long project to turbo charge my old 1995 Nissan Almera 1.4gx I was over the moon when it all worked and i gained 50-60hp kept at 7psi (0.48bar). But then the blow off line came loose and old waste gate stuck closed in testing, it over pressurised system causing head gasket to blow. I fixed these two issues but of course I had huge white clouds of coolant coming out tailpipe with water literally dripping out of it (had to drill hole in silencer to let it drain off water) . So I tried everything. Steel Seal x2, Radweld x 2 different variants, Holts x 2 different variants. Although each made it 10% better they couldnt cure it. Then I tried K seal ultimate. At first I didnt think it would work as after few cycles of heat/cool at tick over it was still smoking 30%, but then I took car 15 min drive followed by leaving it on my driveway at 2,500rpm using pole jammed on acelerator and left it for an hour as last ditch effort...came out and yeeehaaa! no more white smoke pouring out! Just small wisps every now and then and just trace of moisture still in tale pipe. Thanks K Seal!!! If you have any advice to seal that last 2% moisture I would be grateful.
Donna Davis Moore
Aug 26,2018So far so good my daughter's 2007 gran prix 3800 had a head gasket leak we used k seal and it sealed it up really fast next day car was running like it never had a problem thanks for a honest and true product.
Ashworth's IFix
Aug 24,2018Hello. Just passing along a thank you!! I was losing antifreeze in my 2000 Silverado and I couldn't determine the cause. My vehicle was not running hot, nor having any performance issue, just losing antifreeze from Reservoir Tank. I purchased K-Seal Pour & Go (Part #: ST5501). I was reluctant to use it and finally decided to give it a try. It has been 2 weeks since pouring K-Seal in my reservoir and my antifreeze level has not dropped at all. I am thrilled at the results so far. The 5.3l Chevrolet engine is known for blown head gaskets. I have 150K miles on my truck, no antifreeze leaking and I swear the engine is running better even though I didn't notice poor performance. I'm keeping my fingers crossed for a long term or even permanent fix. Thanks again.
Colton Johnson
Aug 18,2018Okay so I have a 2004 Ford explorer and I had a coolant leak for a year now and it was not bad at 1st then all at once it was leaking a ton....... So I did my research and I found K seal with the best reviews and I gone to Walmart and got 1 bottle and gave it a try and I put on 600 to 700 miles on my suv every week and so far so good it fixed it and I'm so HAPPY because I can drive to work knowing it's all good and I have over 231645 miles on my suv and so the leak coming from heater core but it was. buried in JB Weld so I couldn't get to it to fix it it would cost me $1000s just to get it fixed but I put in the k seal and it worked out amazing !!!!!!!! ... Now my friend has the same problem as me so he's ganna try out the K seal today on his truck. This is my new favorite product!
Mark Andrews
Aug 15,2018I bought a bottle of k-seal for a hole in my car’s radiator, which unfortunately didn’t do the job, so after an exchange of emails with the company, I tried another one of their products (Quiksteel) which worked perfectly. Excellent products, excellent customer service.
Mr Gordon Booth
Aug 13,2018Although K-seal didnt work in my case and it later became obvious the damage was too great for it to have any realistic chance of working the aftercare service including an easy refund proccess as promised was of the highest level possibe with also plenty of sound advice given for future reference. I would use this company again without a second thought with the offer of a chat to decide which product would suit best. First class company.
Roger Rolph
Aug 12,2018S-type 2.7 D V6 2004, used daily since 40,000 miles, now 166,000. Was running hot, needing regular small coolant top ups and felt ‘rough’ like using cheap supermarket diesel. Mentioned it to mechanic at Selectatyre Ashbourne during oil change and he said it sounded like head gasket leaking which would write off my old faithful. Recommended trying K- seal which I did next day thanks to Amazon Prime £25.60. I cannot believe the difference, got its zip back, and so quiet and smooth. My only question is how long might it last, and is it worth adding another bottle pre-emptively in 6-12 months? Hope I’m not speaking too soon, but after 1 day I’d say it’s the best £25 ever spent.
Jonathan Roat
Aug 03,2018I had a inlet mainfold leak on my 1999 mgf and white smoke from back. I put k-seal in coolant and ten minutes later all good. No smoke or leak. AMAZING.
Rob
Aug 01,2018Excellent product! Does what it says on the tin
Brian B
Jul 31,2018K-Seal saved our camping trip! While pulling our camper trailer up a steep grade our radiator developed a hairline crack where the top tank is crimped to the core. A bottle of K-Seal and a top-off of coolant and we were back on our way. While their website claims to be a permanent fix, the strain of pulling a trailer through the mountains is more than I'd like to worry about so I still plan on replacing my radiator. But the fact that it got us to our destination and back home is a testament to how well it works.
Jesse De La Cruz
Jul 25,2018I have a 2003 Audi A4 (1.8L), and the head gasket started dripping antifreeze through a side section of the head. Obviously, I knew that it would be a costly repair, therefore; I found this product at Walmart, and after reading the details, I figured $14 was worth it, even though I was skeptical even when I was putting it on my car. After mixing the product for 2 minutes, and pouring it through the main block hose coming from the radiator, (don't forget to put a bit of water on the container and pour any excess left over, DON'T FORGET TO FILL UP THE RESERVIOR with Antifreeze/water after tightning the Main Hose), I noticed that it took 10 minutes for this magical product to work for me, so I decided to drive the car for 20 minutes more, and the leak was completely gone. The following morning, I found a bit of a leak again, (due to overnight engine cooling), but once again I drove it for a while, and the leak dissapeared forever! It saved me $100s in repairs. Thanks!
Istvan Varga
Nov 18,2018A week after purchasing a Peugeot 508 I noticed some coolant loss,1 liter in around 300 miles. I don't think it was a headgasket issue but I took a chance and poured a bottle of K-seal into the system. It worked :) So wherever it leaked it stopped. Great product :)