Bar's Leaks Rear Main Seal Repair, 16.9 oz

I'll start by saying this product goes against everything I believe or have been taught about internal combustion engines, the two most prevailing thoughts before ordering this were: #1: Only oil goes in the crankcase, nothing else #2: Snake oil does not work, especially for a long term solution, fix the real problem instead of throwing money and additives at the problem that ultimately may do more harm than good I have a small block ford engine that has a notorious rear main seal leak, drips engine oil right at the transmission bell housing. Started small and got worse. This is a well documented problem, and the transmission must be pulled to replace the seal. I have heard many stories of people who have replaced the seal, only to have the brand new one leak too, people have tried crankshaft sleeves to make the fit tighter, and with mixed results. I did not want to go down this road unless I had no other option. I did a little research on this product, and the reviews are mixed. I have not heard any horror stories worse than "it didn't help and I wasted my money on this product", and from what I understand it works completely differently than the "leak stop" additives you would use for a head gasket, coolant leak, air conditioning system leak, or tire leak. All the latter leak stop additives are adhesive products which are glues and materials designed to fill cracks/voids and cure on contact with air. This product works differently. This product is not an adhesive of any kind and does not leave any residue. It is basically a solvent that attacks rubber and causes it to swell. This makes the seals fit a little tighter if the only problem is a seal is a little old or dried out. If the seal is cracked, deformed, or a synthetic material that the active ingredient in this product doesn't react with (its designed for rubber, not corks, silicones, etc), this product will most likely not help. I dumped this in the oil reservoir. It was already a little low from the leak, so the excess oil in the crankcase was not an issue. Ran the engine for about 30 mins and no change, still same dripping while running. I drove the vehicle every day approx 30 miles. After a week, the leak was barely noticable, just the bottom of the transmission housing felt a little oily, but no puddle/stains in the driveway. After 2-3 weeks, the leak was gone. And I mean gone, not a drop. I was impressed how well this worked on this problem and thought it fixed it permanently. Then about 4000mi later, I did an oil change. For the first few hundred miles after that, no leaks, then after about 1k miles, I noticed the leak started to return. I immediately picked up another bottle of this stuff and dumped it in, about 1 week later, the leak was gone. I now don't even mess around anymore and just add a bottle of this stuff to every oil change, and it is under control, its a small price to pay (even for life of vehicle) to not have to deal with the rear main seal. For me, this product makes a night and day difference, I have been using it for approx 30k miles, but depending on the root cause of your leak, your mileage may vary.

put over 100 miles on my truck and still leaking

wow , this product slowed my rear main seal leak down 90%

A reliable product focused on getting you back on the road quickly and affordably. It’s designed to provide a practical solution when a leak or unexpected problem brings your day to a stop. Overall, a convenient option for saving time, money, and getting back to life.Help me from a big leak, I used two bottles after oil change, check your car model first because some European vehicle won’t let you use it. But it work on my volwagon temporarily.

Did not make any difference after using it

Slowed the leak. Will update in a few months and see if the leak stops completely.

the main seal leaking is fairly recent… In the last year or two… The product seems to be working perfectly… I think that is very relevant with this issue… but,,,,You can’t expect to pour an additive into your oil ,,and it fixed a problem when it’s been leaking for several years ,,so far I am very pleased.. that’s worth anything. Your results may vary.

I bought 2 of the Bar's Leaks Rear Main Seal Repair with no results. I still have a leak

It blows my mind but it works. The leak stopped after about 100miles. I have a 2011 gmc sierra 1500 2011 with a real main seal leak and it stopped it

Perfect

Excelente producto, muy bien resultado y un precio muy accesible.

المنتج لم يوقف التسريب في السيارة ولا يزال التسريب منذ شهر

Didn't stop the leak for me, but for sure it got better....I was told by the mechanic that with the next oil change I'll have to add another bottle and the leak will stop.