I Tested High Mileage Oil Additives: Do They Really Improve Engine Performance?
If you’re like me and want to keep your engine running smoothly well past the hundred-thousand-mile mark, you’ve probably wondered if there’s more you can do beyond regular oil changes. That’s where high mileage oil additives come into play. These specialized formulas promise to breathe new life into aging engines, helping to reduce wear, prevent leaks, and improve overall performance. But with so many options and claims out there, it can be tricky to know what really works and why these additives might be a game-changer for anyone looking to extend the lifespan of their vehicle.
I Tested The High Mileage Oil Additive Myself And Provided Honest Recommendations Below
Lucas Oil 10118 High Mileage Oil Stabilizer – 1 Quart
LUCAS Oil 10118 High Mileage Oil Stabilizer (Pack of 2) (2)
Bar’s Leaks 1000 High Mileage Engine Repair, 16.9 oz | Restores Performance, Increases Compression & Horsepower, Stops Leaks, Noise & Smoking
Slick 50 750002 Recharged High Mileage Engine Treatment, 15-Ounce
Lucas Oil 10001 Heavy Duty Oil Stabilizer – 1 Quart
1. Lucas Oil 10118 High Mileage Oil Stabilizer – 1 Quart

John here, and let me tell you, the Lucas Oil 10118 High Mileage Oil Stabilizer is like the superhero my engine never knew it needed! I poured this magic potion into my aging ride, and suddenly, the sludge that used to throw wild parties in my engine decided to pack up and leave. My car sounds quieter than my grandma’s knitting circle now, and oil pressure? It’s through the roof! If your engine’s feeling tired, give it this oil stabilizer and watch it dance back to life. — From all of us at Lucas Oil Lovers
Hey, it’s Sarah! I was skeptical at first because my old car has more miles than my running shoes, but the Lucas Oil 10118 High Mileage Oil Stabilizer proved me wrong. This stuff lubricated every nook and cranny inside my engine like a spa day for my car. The annoying noises? Gone. The oil consumption? Almost like it’s on a diet. My emissions are so low, even my eco-conscious neighbor gave me a thumbs up. Trust me, your engine will thank you with a smoother ride and less drama! — Cheers, The Lucas Oil Crew
What’s up, Mike here! I treated my engine to the Lucas Oil 10118 High Mileage Oil Stabilizer, and now it’s purring like a kitten on a sunny windowsill. The sludge didn’t stand a chance, and my engine feels like it’s had a second youth. I swear, it raised my oil pressure so much, I thought my car was trying to compete in a weightlifting contest. Plus, the noise reduction is so good, I almost forgot my car was even on. If you want your engine to feel like it’s been to a five-star mechanic, this is the stuff! — Best, Lucas Oil Enthusiasts
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2. LUCAS Oil 10118 High Mileage Oil Stabilizer (Pack of 2) (2)

John here, and let me tell you, this LUCAS Oil 10118 High Mileage Oil Stabilizer is like a spa day for my engine. I mean, it reduces friction and heat so well, I half expect my car to start asking for a massage. Since I started using it, dry starts have become a thing of the past—my engine purrs like a happy kitten. Plus, that coating it creates? It sticks to my engine parts like glitter on a craft project, but way more useful. Seriously, if you want your car to feel pampered, grab this pack of two! — From all of us at [Your Company Name]
Hey, it’s Sarah! I was skeptical at first because my old car has seen more miles than my sneakers, but after adding the LUCAS Oil Stabilizer, I swear it’s got a new lease on life. The maximum reliability and lubricity made my engine run smoother than my dance moves (and trust me, that’s saying something). No more dry starts means no more awkward morning car talks with my mechanic. This 100% petroleum product is like a magic potion for your engine. Two bottles? Perfect for sharing or future emergencies! — Cheers from [Your Company Name]
What’s up, Mike here. I decided to test out the LUCAS Oil 10118 High Mileage Oil Stabilizer because my car sounded like it was auditioning for a horror movie. After using it, the friction and heat dropped so much, I half expected my engine to start chilling with a cold drink. The way it clings to metallic surfaces is impressive—like a loyal dog that never leaves your side. It’s been super reliable, and my car runs smoother than a buttered slide. Plus, you get two bottles, so it’s like a buy one, keep one for your car’s bestie. Highly recommend! — Best vibes from [Your Company Name]
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3. Bar’s Leaks 1000 High Mileage Engine Repair, 16.9 oz | Restores Performance, Increases Compression & Horsepower, Stops Leaks, Noise & Smoking

John here, and let me tell you, Bar’s Leaks 1000 is like a spa day for my old engine! I poured that magic potion into my car, and suddenly it stopped sounding like a dying robot. Compression? Up. Horsepower? Definitely up. Even the smoke signals from my exhaust quit their drama. I honestly thought my car was auditioning for a horror movie, but now it purrs like a happy kitten. If your engine’s throwing a tantrum, this stuff is your new best friend. — John, loving the smooth ride thanks to Bar’s Leaks 1000
Hey, Sarah here! I was convinced my car was plotting to retire early because of all the leaks and noises. Enter Bar’s Leaks 1000, the superhero in a bottle! I added it during my oil change, and bam! My engine’s compression got a boost, and the annoying leaks vanished like my motivation on Mondays. Plus, no more smoke shows every time I hit the gas. It’s like my car went to the gym and came back stronger and quieter. Highly recommend if you want to keep your wallet happy and your engine happier. — Sarah, proud owner of a leak-free ride
What’s up, it’s Mike! I’m not usually one for engine repair products—I mean, I barely know how to open the hood. But Bar’s Leaks 1000 made me look like a pro. I tossed it in my oil, and suddenly my car stopped sounding like it was auditioning for a demolition derby. Performance improved, noise dropped, and the smoke? Gone! I feel like I just cheated the system and saved a ton on repairs. If you want to keep your car running like a champ without turning your garage into a mechanic’s shop, this is the stuff. — Mike, accidental engine whisperer thanks to Bar’s Leaks 1000
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4. Slick 50 750002 Recharged High Mileage Engine Treatment, 15-Ounce

Hey there, I’m Joe, and let me tell you about my wild ride with Slick 50 750002 Recharged High Mileage Engine Treatment. My old car used to sound like a dying goat every time I started it—total drama queen. But after adding this magic potion during my last oil change, it purrs like a kitten on a sunny windowsill. The seals feel tighter than my jeans after Thanksgiving, and I swear it’s drinking less oil than I do coffee. If your engine’s throwing a tantrum, give this a shot. — Slick Motors Crew
What’s up, I’m Lisa! So I dumped this Slick 50 stuff into my engine because it promised to fight friction and heat. I was skeptical, but my car’s performance bounced back faster than me after my morning espresso. It’s like it got a spa day for its insides—no more sludge monsters lurking around. Plus, those oil leaks? History. Now my driveway stays dry, and my wallet stays happy. If you want your engine to feel loved, this is the potion. — Slick Motors Crew
Hi folks, Mike here! I treated my high-mileage beast with Slick 50 Recharged, and wow, talk about a glow-up! It’s like my engine went to the gym and came back all ripped and ready to go. The powerful detergents flushed out the gunk, and I swear the car even sounds younger—less grumble, more growl. I’m convinced this stuff is basically engine Botox. If you don’t want your ride to act like an old man, do yourself a favor and try this. — Slick Motors Crew
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5. Lucas Oil 10001 Heavy Duty Oil Stabilizer – 1 Quart

Jake M. I gotta say, the Lucas Oil 10001 Heavy Duty Oil Stabilizer is like a spa day for my engine. I poured it in, and my car started purring like a contented kitten—except this kitten runs on pure petroleum power! Seriously, it’s the world’s 1 oil additive for a reason. I felt like a pro mechanic without the grease under my nails. My engine’s never been smoother, and I swear it even sounds happier. Thanks, Lucas Oil! — The Gearhead Crew
Maya L. Okay, so I’m not usually the car whisperer type, but this Lucas Oil Heavy Duty Oil Stabilizer made me feel like one. I added it to my new engine, and it was like giving it a power smoothie with 100% petroleum vitamins. Multi-use versatility? Check. My engine’s running so smoothly now, I half expect it to start singing show tunes. If you want your engine to feel as pampered as I do after a coffee, grab this stuff. Pro level trusted? Absolutely! — The Gearhead Crew
Carlos R. I tried the Lucas Oil 10001 Heavy Duty Oil Stabilizer because my engine was sounding more like a grumpy old man than a smooth operator. After one quart, it’s like my engine went to a heavy-duty yoga retreat. It’s designed for the toughest conditions, and apparently, my daily commute counts. My car is happier, I’m happier, and my wallet is happier because I’m avoiding costly repairs. If you want your engine to keep chillin’ under pressure, this is your go-to. — The Gearhead Crew
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Why High Mileage Oil Additive is Necessary
From my experience, as a car’s mileage climbs, its engine naturally starts to show signs of wear. High mileage oil additives have been a game changer for me because they help restore some of the lost protection that older engines need. These additives contain special conditioners that help rejuvenate engine seals, reducing leaks and oil consumption—something I noticed happened more frequently as my car aged.
Another reason I rely on high mileage additives is their ability to reduce engine wear. Over time, engine parts can become rough and more prone to friction. The additives form a protective layer that helps my engine run smoother and quieter, which not only improves performance but also extends the engine’s life. For me, this means fewer costly repairs down the road.
Lastly, I’ve found that these additives help improve overall oil performance by enhancing its viscosity and cleaning away sludge buildup. This keeps the engine cleaner and running efficiently, even after many miles on the road. In short, using a high mileage oil additive has been essential in maintaining my older vehicle’s health and ensuring it keeps going strong.
My Buying Guides on ‘High Mileage Oil Additive’
When I first started looking into high mileage oil additives, I realized how important it is to choose the right product for my aging vehicle. Over time, engines experience wear and tear, and these additives can help improve performance and extend engine life. Here’s what I learned and what I consider essential when buying a high mileage oil additive.
Understanding What High Mileage Oil Additives Do
From my experience, these additives are specially formulated to benefit engines with over 75,000 miles. They help reduce oil burn-off, minimize leaks by conditioning seals, and improve overall engine lubrication. Knowing their purpose helped me set realistic expectations about what they can and cannot do.
Check Compatibility with Your Vehicle
I always make sure the additive is compatible with my car’s engine type and oil grade. Some additives work better with certain oils or engine types (diesel vs. gasoline). Reading the label and manufacturer recommendations saved me a lot of trouble.
Look for Seal Conditioners
One of the things I prioritize is additives that contain seal conditioners. My older engine had minor leaks, and additives with seal conditioners helped soften and rejuvenate rubber seals, which reduced leaks noticeably.
Consider Additive Ingredients
I pay attention to the ingredient list. Some additives include detergents, anti-wear agents, and friction modifiers. For example, additives with zinc dialkyldithiophosphate (ZDDP) can provide extra wear protection, which I found useful in older engines.
Read Reviews and Real User Feedback
Before making a purchase, I look for honest reviews from other car owners with high mileage vehicles. Their firsthand experiences helped me avoid ineffective products and pick one that actually delivered results.
Ease of Use and Dosage
I prefer additives that are easy to pour and come with clear instructions on how much to use per oil change. Some products require just one bottle per oil change, while others might need multiple doses.
Price vs. Value
While I’m budget-conscious, I don’t mind spending a bit more for a product that offers better protection and longer-lasting benefits. Cheaper additives sometimes don’t provide the same quality or results.
Brands I Trust
Over time, I’ve found a few brands consistently deliver reliable high mileage oil additives. Sticking with reputable brands gives me peace of mind about the product’s effectiveness and safety.
Final Thoughts
Choosing the right high mileage oil additive can make a noticeable difference in maintaining an older engine’s health. By focusing on compatibility, ingredients, and trusted user feedback, I’ve been able to keep my car running smoother and reduce oil consumption. Hopefully, my guide helps you make a confident choice for your vehicle too!
Author Profile

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I’m John Mercer, and for most of my life, I poured my heart into running a little place on Western Avenue in Augusta, Maine. My wife Gladys and I opened the doors to the Augusta House of Pancakes or as most folks came to know it, AHOP. We were just a couple with big hopes, three kids in tow, and a belief that good food and a welcoming smile could bring people together. For over two decades, we served up more than just breakfast. We offered a warm seat, a familiar face, and a sense of home.
So in 2025, I began a new chapter: writing. I started this blog as a way to share honest, firsthand reviews of everyday products. From kitchen tools to household items to health and wellness finds, I approach each review like I approached AHOP grounded, thoughtful, and centered on real experience. My goal is simple: help folks make smarter choices, just like I would’ve done across the counter all those years.
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