Best Engine & Oil Fluid Additives of 2025

"I recently transformed my 2016 Mustang Ecoboost with the LIQUI MOLY Oil Additive Cera Tec 3721. I was initially concerned about a knocking noise, but after using this product, it was like a game-changer. The ceramic wear protection really reduced friction, and I noticed a significant reduction in noise and an overall smoother performance. Plus, it improved my fuel efficiency, allowing for more adventures on the road. I highly recommend it for anyone wanting to enhance their vehicle’s performance!"

"I bought this product for the first oil change in my Mazda 3 Turbo. Initially, I considered using another product, but I opted for Ceratec because it doesn't darken the oil. The results were fantastic—valve noise decreased significantly, and the engine felt smoother and more powerful. I even used it in my girlfriend's CX30, and the difference was night and day! The engine was much quieter, and I was genuinely impressed. It’s a bit pricey, but I see it as cheap insurance for the longevity of my car."

"After using this product, I noticed my car runs more smoothly and the noises have improved. It's been a great experience overall!"

“I had heard about Liqui Moly but never tried it until my friend bought a BMW M3. After researching, I found it to be the best oil brand in Germany. I mixed it with Amsoil for my Mustang GT and my girlfriend's Sonic. The difference was amazing! The Sonic's MPG increased by over 6%, and my Mustang became whisper quiet. I was sold on this product!”

“I recently added the MSO2 to my Chevy Express van with 200,000 miles. Right after I poured it in, the engine became noticeably quieter. After driving for just 5 minutes, it felt like I was driving a new vehicle. I also noticed an increase in oil pressure. I usually don't like additives, but this one is a game changer. I’ll be using it for all my cars from now on.”

“I put Liqui Moly in my 2017 Honda Civic with a 1.5 turbo engine that had a ticking noise. After using it for about 80 miles, I noticed less vibration and a significant reduction in ticking. The engine runs smoother and I’m considering trying their Molygen oil for my next oil change since this product impressed me.”

"I used it on my 2011 Subaru Forester, and it virtually stopped the engine's oil burning. Before this product, I had to add a quart every few hundred miles. Now, the oil isn't darkening as quickly. I highly recommend this!"

"After adding the Liqui Moly Oil Saver to my 2011 BMW 328i, I noticed the oil leak stopped completely after about 800 miles. Initially, I was skeptical, but my car runs more smoothly, and the oil temperature is lower. Just be patient; it does work!"

"I had a smoking problem on startup due to old valve guide seals. This product fixed it immediately! Although replacing the seals is the proper repair, this was a cost-effective solution for my older car. I'm hopeful it will also reduce oil consumption."

"I have now used half of the bottle. Never had a problem with stiction or gunk. Power and fuel economy continue to be good. I will finish this bottle and, hopefully, keep driving for another 100,000 miles."

"My 2000 Excursion hated the cold lately. After using less than the recommended dose, it smoothed out all the injectors and ran great. Not saying my injectors don't need replacing eventually, but this was amazing to say the least."

"I used this in my Chevy Equinox 2012. Had dark smoke and shaky starts. After using half the bottle and driving around 200KM, I have no more dark smoke, and the engine runs smoothly now!"

"I've always recommended using STP for ZDDP antiwear additive. It’s super slippery, sticks to internal parts, and reduces audible piston pin slap."

"I mixed STP with my engine oil after feeling low power in my car. It made the engine much smoother than before, especially since I have over 50k miles on it. I highly recommend it!"

"I used this product to thicken my truck oil for a chainsaw. It worked so well that I no longer feel the need for special chainsaw oil!"

“I was impressed with how well this product helped reduce oil consumption and leaks in my 2008 6-cylinder car. Although there’s still a leak somewhere, it’s not leaving much on the ground anymore. I’ll likely continue using this after each oil change until we eventually get rid of the car.”

“I had high expectations for this product. I own a 1995 Chevrolet C1500 that had a bit of smoke on startup and dropped a few drops of oil daily. I followed the instructions precisely, but I’m giving it one star because I believe the smoking is actually worse now. I wish I had kept that $20.”

“I use this in my 1966 Ford F-100 with the original drivetrain and 139,000 miles on the V8 engine. The rope seal for the rear bearing always leaked, but this product slows it down when used regularly during oil changes. It doesn’t completely fix the leak, but it does help.”

"I've noticed that my engine runs much smoother and the noise has decreased significantly. It feels like it has more power and responsiveness now!"

"After using this product, my 2004 Forester is quieter and smoother. I think my fuel mileage has improved, though I need to confirm it."

"Using this in my 2011 Jeep Wrangler has made it quieter and it feels like I’ve restored some power. I really trust this product!"

"When I took my 1998 Honda CRV to the shop, I was told I might need a new motor or expensive repairs for the cylinder #3 piston ring due to a poor compression test. After using Rislone High Mileage, I noticed a smoother idle and, surprisingly, the check engine light turned off! I'm genuinely grateful to the makers of Rislone for giving me peace of mind."

"I'm not usually one for oil additives, but after buying a 2009 Pontiac Vibe that was using oil excessively, I decided to give this a shot. After a couple of treatments, it’s using much less oil now, which makes me happy as I can hand it down to my daughter for driving lessons!"

"I had a 1984 Simplicity mower that was burning oil and fouling spark plugs, but after adding Rislone, the smoke reduction was almost immediate. The engine ran smoothly, with no oil consumption. I was about to sell it, but now I believe it will last for years to come!"

"I initially hesitated due to the cost, but after using this product in my '87 Jeep Grand Wagoneer, I was amazed. It made my engine run so much quieter and smoother, and even increased the idle speed by about 150 rpm. The valve tick is still there, but it's much softer. In this heat, my engine temps stay cool, even with the A/C on. I hope to get an extra 50k miles out of my old motor!"

"I’ve been using XADO Engine Oil Additive for years across various cars, and the results are consistently fantastic. My engines showed wear, with reduced compression and increased oil consumption, but after applying this additive, the improvement was noticeable almost immediately. It made my engines run smoother, quieter, and more powerful while dropping fuel consumption. It's easy to use and works with all engine types!"

"I was skeptical about this additive because of the price, but I noticed an immediate improvement in acceleration after using XADO Maximum Twin Turbo. It felt like my turbo was boosted even more. Despite a little mess during application, my engine now runs smoothly and quietly. As a long-time XADO fan, I can confidently say this product is worth the investment!"

"Bar's Leaks High Mileage Engine Repair is a miracle worker for pesky oil leaks. I was pleasantly surprised by its ease of use and how quickly it worked. Within just a few days, my oil leak was gone, and I didn't have to spend a fortune on repairs!"

"I had a misfiring issue in my car, and after using this cleaner, it worked wonders! Within an hour, everything was cleared out, and I've managed to skip a tune-up for over a year. I highly recommend it for older cars and trucks with leaks."

"Initially skeptical, I poured this product into my 1999 Honda Accord with an oil leak. To my surprise, it worked within a week, and the leak stopped completely. I later tried it on other vehicles without success, but for mine, it was a game-changer!"