Pro-Seal Stop Leak Treatment – Stops Oil & Fluid Leaks in Engines, Transmissions, Power Steering, Differentials & Hydraulic Systems | 8 oz | Made in USA

My 1997 Honda CRV was leaving oil all over my driveway. I changed the oil pan gasket but it didn't stop. Suspect the main seal is bad. Was losing about 2 QTs a month. Put this in and after a month was losing around 1 1/4 QTs of oil. Seems to have slowed the leak. I've since added a second treatment and will wait to see if it stops the leak completely then update my review. Also used in a 1998 Honda CRV that loses just over a QT of oil a month but with no drips on the driveway. It didn't do anything in that case so I suspect the oil in that case is getting burned out the tail pipe. This stuff won't help with a worn engine just old seals. Update:. After second treatment didn't really do much more to stop my oil leak. Still losing at least a quart per month. 4/5 stars because it did do something. Second update:. I put Restore oil stop leak in my engine and my oil didn't go down a drop anymore. I suspect I had two problems: (1) blowby around the Piston rings and worn cylinder walls which the Hapco product could not fix, and (2) bad main seal which the Hapco product fixed. However after a few weeks of using Restore I noticed puddles of oil on my driveway. A lot worse than before. I think the Restore, in the process of stopping oil from burning, also increased the oil pressure and oil is now blowing out around the main seal again. Will order this product once more and see if it will fix the seals again. Update:. After adding Hapco a third time the oil leak has stopped completely. I am convinced that this product works with enough treatments. I am also convinced that most oil loss is a combination of leaky seals that Hapco will fix and blow by around piston rings or worn cylinders that Restore will fix. If you see oil puddles on your driveway then you definably need Hapco. If you don't see leaks anywhere then use Restore. Both together will certainly end oil loss. Update: I’ve used this on a hydraulic jack too with dried out 30 year old seals by adding a few tablespoons to the hydraulic oil and after a few uses the leak stopped. This stuff works but requires additional treatments over time or the leaks will start up slowly again. One bottle will not get you though to the next oil change if you are running full synthetic oil with extended life filters doing oil changes just once a year or every 14,000 miles. Plan on adding additional bottles in that time. You will probably need to add a full bottle every 4 months depending how bad your leak is.

(See 12 month update at the end of my review) Not 100% sure this will work, however I am giving 5 stars because of the company's great product service. I called Hapco Products regarding how I wanted to use the product. I have a Honda ST 1300 motorcycle that has a very slow leak in the hydraulic clutch system. Note the clutch system is completely separate from the brake fluid system. The clutch system uses DOT 4 brake fluid as its fluid. When I called Hapco the guy I spoke to took the time to talk to an expert at the company. They told me that it should work with my system as long as the clutch fluid and brake fluid are separate systems, which they are. They told me not to use it in the brake system. I thought it was very nice of them to bother to answer my question. I just installed it today and I will update this in a few weeks as to whether it worked for me or not. I believe I have a very small leak around a seal, so I believe it will solve the problem. Update: It has been about 6 weeks since I installed this and have used the bike several times, clutch fluid level is now stable, so no more leaking clutch seal. The product worked as expected. Update 12 months later. Bike sat in my pole building for 8 months and still no leakage from the seals. During winter storage was the time the seals would leak the most. So using this product saved me a ton of money as I did not have to get the transmission seals replaced.

Purchased 2pack. Used one in a v8 Toyota engine for a tiny rear main seal leak. Seems to have stopped or slowed it down. I don't see any more tiny drips I used to see every 3 weeks to a month. The second bottle I used in a power steering leak but that didn't help and was my fault as the leak was beyond a seal stopper liquid treatment. However if you do have a heavy power steering leak you can't use a lot of this by itself as it's oil is very thin and will pass thru any seals and not stay in the system to do it's magic. It has to be used with power steering fluid or something thick. If any leak you have is leaving large wet stains on the ground every second the engine runs this nor any other product will not work.

I purchased two of these for two different vehicle leaks. I reviewed this product and it seemed to get decent reviews. One bottle seemed to work fairly well although the car still has a slight drip. On the other one, it didn't work at all. I was hoping this would slow down the leaks until I had the time to replace the leaking gaskets. It did do that to one of the cars so I am giving it five stars. I've had better luck in the past with sealers that were more viscous. This product is like water. I'll probably go back to the other brands if they are needed in the future.

I have tried every brand out there to seal my power steering leak and I’m at my last resort to taking it in to the shop. I actually took it into a Nissan stealership and they told me there wasn’t a power steering leak and replaced the gasket covers for $700+ My car clearly has a power steering leak still, but the Nissan stealership refused to believe me on the first check-in. Maybe they didn’t want to deal with an older 98 Nissan Maxima, but the entire experience felt like a scam. I’m running through PS fluid like crazy since it’s warmer outside. I put the entire bottle in the power steering reservoir and I’ve been driving around a lot to circulate the formula into the power steering system. I’m still getting a few drips of power steering, but it’s a lot less. It leaks more with the car on an incline vs level ground. Another product called ATP worked 2-3 months to slow it down on a 98 Nissan Maxima, but I’m hoping Hapco seals it completely. I believe the PS leak is coming from my right steering rack in which I can clearly see power steering dripping from it. I will update this review if it seals the power steering leak or I obtain better results. Wish me luck.. Update: 4/9/2021 Car still drips power steering on the driveway. I have tried everything and I mean every snake oil out there. Nothing has sealed a steering rack on my car. It only slows the leak and after some time it’s a full blown leak. It’s time to get it fixed right, but I really don’t want to drop 2k+ on a ridiculously old car.. Save your money and just get it fixed. 4/10/2021: Car is slam empty in power steering reservoir. I filled up with power steering fluid and the leak has slowed down to a few drips. ATP does the same thing for half the price. Lesson learned replace rack and pinion!

Didn’t stop the leak in the transfer case. But to be fair to the product the output shaft seal, it turns out, was really worn out ! Probably the only remedy to the leak was replacement of the seal which I did. I’ll probably try the other bottle in engine or transmission at some point. It’s probably a good product when used in less serious leaks !

I have a beautifully restored 1951 Ferguson farm tractor that had a very slow internal seal leak in the hydraulic 3-point hitch lift. With the engine running, the lift operated just fine. However, if you left the implement raised and shut the tractor off, the implement would slowly lower to the ground. This was annoying, but not worth taking the whole thing apart to replace seals, etc. I found this Hapco Pro-Seal and the good reviews looked like it would be worth a shot. Since the hydraulic system takes 6 gallons of gear oil, I added one whole bottle of Pro-Seal to see if it made any difference. After just an hour or so of normal operation, the leak-down issue was completely fixed! I've put about 50 hours on it since then and it's still working perfectly like new! Not bad for a 70-year old tractor. I'm convinced. This stuff works. Thanks Hapco for such a great product at a reasonable price. You saved me hours of labor and more money in replacement seals.

Been using for years before it was on Amazon. Amazing stuff...really works!