Pelletized Heavy Duty Stop Leak (PLT11)

  • Can Bar’s Leaks® be installed in existing antifreeze?

    Yes, this product is specifically designed to be directly added to the cooling system without having to flush out the antifreeze.

  • Will Bar’s Leaks work in the new extended life antifreeze?

    Yes, Bar’s Leaks is compatible with both conventional green or blue (silicate-based) and extended life red/ orange or yellow (OAT/HOAT) antifreeze.

  • How does Bar’s Leaks work?

    Bar’s Leaks will seal internal, external and coolant to oil leaks. Once installed, the Bar’s Leaks particles shrink up to 15 percent. On an external leak, the tiny particles flow to the point of the leak. They then collect at the outside of the seepage and build inward. For internal leaks, the Bars Leaks particles will burn when subjected to the 5000 degree heat of the combustion chamber to seal minor head gasket seepage and small cracks. On coolant to oil leaks, where coolant can seep into the crankcase contaminating the oil, the tiny Bar’s Leaks particles will seal the pores in cast iron and aluminum preventing seepage.

  • How long does it take for the Bar’s Leaks to work?

    We recommend you drive/idle vehicle for 15 to 30 minutes. In most cases the leak will be sealed with in this amount of time. If the leak is not sealed, a second application maybe required.

  • Will Bar’s Leaks plug my heater core?

    No, the tiny particles will pass through a 24-gauge mesh screen which is the spec for the BIG 3 car/ truck manufacturers. They say that any product installed in the cooling system must pass through this screen. Bar’s Leaks is one of a few stop leak which pass this test and to be approved by the vehicle manufacturers. Note: If using Bar’s Leaks to stop heater core leaks, make sure you turn your heater control to HOT. Some vehicles have a valve that controls coolant flow through the core.

  • How do I pre-dissolve pellets?

    The easiest way is to pour the liquid from bottle into the radiator and then add hot water to the pellets in the bottle. Shake bottle for a few minutes to dissolve pellets.

  • What are the dosage recommendations?

    Use 1 bottle for 6, 8 and 10 cylinder gas or diesel engines. For 4 and 5 cylinder engines, use 1⁄2 of liquid and pellets. One bottle treats systems up to 4 gallons.

  • I accidently added the Bar’s Leaks Pelletized Stop Leak into my gas tank, what should I do?

    Bar’s Leaks Pelletized Stop Leak is only designed to be added to the cooling system. If the product is installed in the gas tank, the tank should be removed and cleaned out by a professional mechanic.

  • I accidently added the Bar’s Leaks Pelletized Stop Leak into my engine oil, what should I do?

    Bar’s Leaks Pelletized Stop Leak is only designed to be added to the cooling system. If the product is installed in the engine oil and the engine has not been started, in many cases you can remove the valve cover and drain the oil leaving the drain plug off. Then use an engine flush washing out the head keeping special attention to the oil return holes that run down to the oil pan. Clean these out and pour the engine flush down these holes flushing everything into the oil pan and out the drain hole. If the engine has been run, you need to take the vehicle to have a professional mechanic evaluate what can be done to clean the inside of the engine. This might include taking the engine apart to clean all of the parts.

  • I accidently added the Bar’s Leaks / Rislone Radiator Heavy Duty Stop Leak to my overflow / reservoir what should I do?

    It is our recommendation to drain and flush the overflow / reservoir then install the product directly into the radiator.

Our Bar’s Leaks Pelletized Radiator Heavy Duty Stop Leak is specially formulated to seal larger leaks better than other stop leak products. You’ll find plenty of powder formula radiator stop leak products on the market, but you won’t find a seal coolant leak solution that beats ours in effectiveness. Our Pelletized Radiator Heavy Duty Stop Leak is versatile, too, working safely and effectively on plastic, aluminum and metal radiators, heater cores, gaskets and freeze plugs. It also has a water pump lube that lubricates water pump seals and inhibits the formation of rust and scale.

Simply put, it’s the fast, effective, easy-to-use powder formula radiator stop leak that’s just as simple and straightforward for a regular driver as for an experienced mechanic. Convenient solutions to seal coolant leaks shouldn’t be limited to just those with advanced automotive knowledge, which is why each product in our catalog is designed to meet the needs of anyone who gets behind the wheel of a vehicle.

In under an hour, you can quickly and easily solve that once-dreaded leaky radiator. Give it a try and get your car back on the road in no time.

Effective Solutions from Chemical Experts

Not every product that claims to stop seal coolant leaks actually works as advertised. In fact, many of the products actually can make the situation worse. But, at Bar’s Leaks, our powder formula radiator stop leak and other products are developed by the best chemical engineers in the industry. These products are proven to alleviate leaks related to cooling systems, head gaskets, engine oil, power steering, transmission and other vital components. The goal with each product is to get you back on the road as quickly and affordably as possible.

Our history of serving vehicle owners stretches back nearly 70 years. Our status as the industry’s best-known brand has emerged from our long track record of successfully developing products that are easy for everyday drivers to use. Bar’s Leaks manufacturers its products right here in the United States, just an hour outside of Detroit. When you want to mild and moderate stop seal coolant leaks at the fraction of the cost of taking your car to a professional, choose powder formula radiator stop leak from Bar’s Leaks.

Learn where you can find Bar’s Leaks Pelletized Heavy Duty Stop Leak near you

Leave a Review

  • “I wanted to write and let you all know that I am so very happy that your product is one that works… I only wish that I would have trusted in this process a little while sooner. My wife’'s van developed a leak that came from the underside of the rear of her engine. After careful inspection by both me and a local repair shop, it was thought that either the intake gasket had failed or the head gasket. I spent two and a half days breaking the entire engine apart and replacing the intake gaskets and putting it all together just to once again see the leak when I was all complete. As frustrated as I was, I went to the local parts store and shared my frustration. They recommended Bar’s Leaks Radiator Heavy Duty Stop Leak. To be honest, I wasn'’t much of a fan of those stop leak products but I sure didn'’t want to spend another $300-$400 on replacing the head gaskets and the intake gaskets (of which I just replaced hoping it was the least of the two projects). I bought a jug of your product serial number 046087000472 and within 20 minutes of running the car, THE LEAK WAS GONE!!! I can’'t believe it!

    It has been almost 4 months since I did this weekend project and still no leak! I just wanted to let you all know that you have changed my thinking about Bar's Pelletized Stop Leak. I will recommend your product to anyone who has a leak, before they repeat what I did and spend all that money on a wasted weekend of frustration. Thank you!”

    D. C. Sr. - Hayward
  • “I am an ASE Master Technician and have 25 years of experience. Recently my work truck ('99 Ford Ranger 4x4 3.0) developed a severe coolant leak from a failed timing cover gasket (quite common on the 3.0 "Vulcan" OHV engines). I was a long ways from the shop and it was around 15 degrees out (not warm enough to work outside in my book). Filling the cooling system with coolant took about 5 minutes before the coolant was too low to circulate. I have never been one to use a stop leak product before, but I decided to give it a try. Im glad I did. Stopped up the leak like magic. Worked so well that i haven't had to repair it yet (a month so far). Heat and cooling system still working just fine. Thanks for a great product that delivers!”

    Steve H. - Des Moines, IA
  • “I guess this is not a question really, but a testimonial. I work in the fast lube industry, and deal with additives every day. When I had vapor and fog coming out of my vents in my '96 F350 with a Powerstroke Diesel, my heart sank, having replaced it less than 6 months ago with a new core.

    I will admit, when the idea of radiator stop leak products came to mind, I doubted it would work. I don't really believe in pour in fix-alls just because of the additives I sell, I don't really believe in. I went out on a limb and got a bottle of Pelletized Stop Leak and poured it in the top hose, after dissolving the pellets in hot water. I poured it in and didn't expect anything to happen. Drove it for 5 minutes, and my windows were fogged up. I cleaned the windows and kept driving. Only a little fogging, and after 20 minutes it was done. Fixed! I couldn't believe it.

    I would definitely recommend this to anyone I know. I remain skeptical of other "rebuilds in a bottle" but I would sure buy Bar's Leaks again. Bar's, thank you for making a great product that actually works. Feel free to post this as a testimonial. Love the product!”

    M. L. - Pleasanton, CA
  • “I used The Radiator Heavy Duty Stop Leak in my 96 Acura TL 2.5 five cylinder car with 220,000 miles. I don't have a temp gauge that goes past the midway point anymore. The cooling fan doesn't kick on anymore. I don't have white smoke coming from the hood area anymore. The product did what it is supposed to do -- it sealed up an internal leak in my cooling system my eyes could not see. I will be checking into some of your other products, if and when the time comes. Thanks for putting out a product that WORKS.”

    K. B. - Newnan
  • “The heater core in my GMC truck was leaking steam from a tiny crack. Required removal of entire dashboard to repair -- either a $600 job at a shop or two days laying on my back in the truck trying to do it myself. Tried the Alumaseal brand, it didn't work.

    With little hope left, I bought an 11 oz bottle of Bars Heavy Duty Stop Leak, poured it in, and started driving the truck around on errands. About 45 minutes later, the steam coming out of my heater vents suddenly stopped and the smell of anti-freeze vanished. The leak was fixed and has stayed that way since. Thanks for saving me $600, Bar's!”

    S. T. - Los Angeles, CA
  • “I used the PLT11, Heavy Duty Radiator Stop Leak. I own a 1991 Nissan Maxima with 95,000 miles on it and for the past few months it started to leak coolant. I think it was in the water pump seal area or even the heater core, anyway I added the radiator formula and not only did it stop the leak, the heater works like it did when new. Thanks.”

    G. G. - Easton
  • “Over six months ago our 1995 Chevy Lumina (70k miles) started leaking from the radiator. I put in Bar's pellets and no more leak. I also started using Bar's Rear Main Seal leak stopper at every oil change in my 1995 Pontiac Grand Prix (200k miles)and it has drastically decreased my oil leak. Here is the one that blows me away though. That same Grand Prix developed a bad radiator leak about 3 wks. ago. I put Bar's pellets in and the leak stopped. For a few days that is. The leak came back again and then stopped again. This proceeded for about three weeks. But my car never ran hot. Finally, I replaced the radiator this past weekend and to my surprise there was a 3inch crack in the plastic tank on the drivers side of the radiator. The crack had even started to spread apart. It was very easy to locate once the radiator was out of the car. I was amazed that the Bar's product kept filling in the crack and allowing me to continue driving. I am telling everyone about it. This product is amazing.”

    J. G. - Louisville, KY
  • “Your testimonial pages are no joke! Wow!

    I have always been leery about adding anything at all to the coolant systems in my cars over the years. But this time, facing a major repair bill, I decided I have nothing to lose other than about five dollars. I drive a 1996 Monte Carlo 3.1 V6 (which by the way has been notorious for having lower intake manifold leaks) the low coolant light came on a few weeks ago. In a matter of a few miles after that, I was burning coolant in my exhaust and it was leaking out of the intake, spraying onto my serpentine belt and basically making a mess in the engine compartment. I talked to a few of the guys I work with (old-timers) and they recommended using Bar's Leaks. I was definitely hesitant, but trusted their judgment. The next day I bought the pellets, used it accordingly, and in amazement, I have driven about 5,000 miles since, with no leaks, no squealing, and no mess. The engine runs smooth, quiet, no smells and best of all, doesn'’t over-heat! While I'm sure your product won't fix everything, it definitely fixes those nuisance problems. It saved me almost $700 in repairs, and for that, I thank you very much.”

    C. H. Catasauqua - Pittsburgh, PA
  • “I own a 1999 Chevy Suburban and a 1992 Pontiac Bonneville. Both cars are daily drivers and have used your fine products now for five years. Bar's Pelletized Stop Leak is without a doubt the finest product on the market. It simply yet elegantly works and does what it promises. Both cars had leaks and one treatment with your Bar's stopped all leaks within twenty four hours, outstanding performance and value and overall a very solid product. Well done and many thanks and my personal wishes for a safe and happy new year!”

    Roy R. - San Antonio, TX
  • “I told you I would tell you my Bar's Leaks story someday. Here it is: I drove a 1994 Chrysler Concord for 8 years it had 285,000 miles on it when I sold it. I drive 100 miles round trip to work everyday. One winter morning I left for work and noticed the temp gauge getting hot so I figured it had frozen up. So I stopped and let it sit for 15 – 20 minutes and then resumed my trip to work. It started getting hot again but I figured I could make it which I did. I checked the coolant level at lunch and it was low so I went and got some and filled it up. I drove home and everything seemed fine until the next morning when I had the same problem.

    The car had about 220,000 miles at this point and I knew I did not want to put money into any major repair, so I checked the internet to see if I could find any info or reviews about Bar’s Leaks. I remember a mechanic buddy once telling me it was one of the few automotive chemicals on the market that worked. I found nothing but positive stuff on the net so I tried it and it stopped the leak for 2 years.

    I had to put a bottle of the heavy duty stop leak in every 6 months for 2 years and then the leak got real bad. So as a last resort effort I did the flush, rinse head gasket repair and then the heavy duty stop leak and drove it for another year and a half before selling it. I never determined if it was a bad head gasket or a cracked head but the leak was on the right head at the rear of the engine. So for about $25.00 - $30.00 I drove the car for 65,000 miles.

    I know the product works and tell everyone I can about it. The guys here at work razzed me about it but a lot of them have used since I started raving about it. I have been telling everyone who asks or tells me they are having a coolant leak problem to try Bar’s Leaks as it has worked for me.”

    B. B. - Michigan