Bar's Leaks CONCENTRTD REAR MAIN SEAL

Perfect

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.

NOT WORKING

Doesn't really work.

Broke engine crank oil siel

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.

A new puddle under my car led me to find the rear seal had sprung a good leak-A bit of research showed it to be an expensive fix for my model of car in a shop and a big effort for diy on a fairly high mileage car. I was a bit nervous to use an additive in a turbocharged car as a friend had advised me against it with no real explanation. I removed the belly pan, washed 10 years of oil build up from other weeps and minor leaks off of the engine and belly pan before adding the bars leak in with my oil change as instructed- It’s been about 3 months of occasional but aggressive driving and zero leaks detected. No other problems either.

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

We had a minor, small leak in our rear main seal and our mechanic recommended that we try this product. Following instructions, I applied it and then drove the prescribed number of miles. And this worked! No more leaks! I was hoping for a reduction at best and was skeptical that it would stop the leak. Not only did it work as hoped but it continues to work. We all know that worn parts do not get 'better' and I know at some point the seal must be replaced. The low cost of this seal repair has postponed that repair for months at least and perhaps even for years.

I’m a mechanic and I was always told by my predecessors not to use anything like this, “snake oil” like the use to call it. So I used it and my rear main seal stopped leaking. It’s just a matter of time to remove my transmission and replace the gasket. For a quick fixed this is all right.