Best Engine Flushes of 2026

"I was amazed by how clean the dipstick looked after using this engine flush on my high-mileage Altima. It removed so much sludge and gunk that I had to check by touch to confirm the oil level. This product left my engine cleaner than I ever expected."

"After using this flush on my old truck, the ticking noises and oil burning stopped, and my gas mileage improved noticeably. I followed the recommendations to rinse with cheap oil first, and now the engine runs so quietly and smoothly, it's like a new truck. I'll definitely make this part of my regular maintenance."

"When I bought a used Jeep, it had a loud ticking and the dipstick was covered in varnish. After treating the engine with this flush, the oil came out jet black and the engine is now much quieter and smoother. If nothing else, it clearly cleaned out a lot of carbon and sludge from inside the engine."

"I love how this product dissolves salt quickly and keeps my boat and fishing gear looking clean after every trip. Just a spray and rinse—no scrubbing required!"

"I've been using this since I got my jet skis, and it's worked perfectly. No problems so far, and it's much cheaper than buying from the dealership."

"The applicator and cleaner do a great job, but be careful, the plastic jar’s bottom can blow out if you’re not gentle."

"I bought this to flush the lubrication system of my daughter's used Jeep Wrangler, and it worked perfectly. After running with it for 50 miles, the oil came out pitch black, showing just how much sludge was cleared out. Months later, the engine is still running smoothly, with no valve tick and consistently good fuel economy. This product made a noticeable difference and I'll keep using it before switching to my preferred oil."

"I put off my oil changes for way too long—about 25,000 miles. After using this, my fuel efficiency went from 38 MPG back up to 46-51 MPG, just like when the car was new. It's been over a month and the improvement is still there. If your oil system is dirty, this can really restore lost performance."

"My 2015 Chevy Cruze and old '73 Chevy CK10 both benefited from this product. The oil drained out much darker, and the old truck's valve lifters looked more polished. The CK10's compression improved, almost eliminating oil burning and smoothing cold starts. I highly recommend it for both older and newer engines."

"After using this, I was able to pass my emissions test without any hassle. I let the product soak longer than recommended and made sure the converter was hot. The amount of buildup it cleared out was amazing, and now I keep a can in my garage just in case."

"I followed the instructions exactly, even swapped out both O2 sensors, but my check engine light kept coming back. The inside mesh still looked fine and probably just needs a thorough cleaning. For me, it didn’t solve the issue as expected."

"The trickiest part was getting to the upstream air/fuel sensor, but once I managed, the process was straightforward. After using the product and replacing the downstream sensor, my P0420 code disappeared, and fuel mileage improved. Overall, I'm very pleased with the results so far."

"I've used this engine flush on everything from high-performance V8s to 4-cylinder engines, boat motors, and even lawn mowers. Every time, I notice smoother, quieter performance and much cleaner oil. In my 2004 GMC Sierra with over 225,000 miles, it genuinely made the engine feel like new again. After following up with another oil change, I could see the flush really pulled out all the dirt and sludge. Seeing is believing!"

"After buying a used John Deere lawn tractor, I added this flush even though the oil looked clean. When I drained it, the oil came out dark and dirty—proof it works. I highly recommend it, but make sure not to run the engine under load for too long during the flush. Clear instructions on usage are available online."

"My 2010 Land Rover LR2 had started sounding rough and noisy, almost like a diesel truck. After just one use of this flush, the engine already sounded much smoother. After a second use a few months later, it truly felt like a new engine."

"I've tried several Blue Devil products and they've consistently delivered. They've saved a few of my engines from being scrapped, and the ones that didn't work out were refunded without hassle. For me, it's always a win."

"I ran this cleaner through my Duramax and it totally cleared out the oil system. I'd strongly suggest giving it a shot before switching to higher-end oil."

"Honestly, I can't say for sure what fixed my truck's lifter tick, but after adding this to the oil, the noise stopped. Even though I still use cheap oil, the peace of mind is worth the cost."

"I used this flush on several of our family’s Chargers, which are notorious for engine sludge. After just a few oil changes, the crankcase looked noticeably cleaner—I could see the difference when changing the valve cover gaskets. For the price, this is worth using regularly."

"After struggling with a persistent engine tick, I tried this flush and, to my amazement, the noise disappeared within five minutes. This stuff really works wonders!"

"I give it five stars for how thoroughly it cleaned the engine and for not causing any leaks or gasket issues. But be cautious: if you have heavy sludge, make sure to drop the oil pan to get everything out. Otherwise, you might risk clogging the oil pickup, like I did."

"My truck was practically dead, barely idling and constantly stalling, until I gave this product a shot. I was shocked when it brought my 2010 F-150 back to life, letting me squeeze out another 7,000–8,000 miles before finally selling it. Seriously, this stuff worked wonders, saving me a ton of money on repairs."

"I tried this flush on my Kia with 165,000 miles, following the directions carefully. The engine felt noticeably smoother after using it, and the oil came out much darker, showing it really cleaned out a lot of gunk. Definitely noticed a positive difference."

"I usually avoid engine flushes, but since I knew my Saturn Ion’s maintenance history, I decided to experiment. The flush did seem to remove some buildup, though it’s hard to judge exactly how much. Still, it did something, and the process was straightforward."

"I found this product very simple to install and it did exactly what I needed. The connection felt secure and snug, though I do wonder about how long the plastic will last."

"After buying the right adapters, flushing my engines became super easy with this. It’s really a convenient, hassle-free solution after a day on the water."

"I realized I didn’t actually need this part—my Seadoo Sportster can just use a regular garden hose for engine flushing. It's still in the package for me."

"I was surprised by how thoroughly this cleaned out my AC system, even when it was packed with metal shavings and gunk. After using it, I could confidently install my new compressor and AC parts. If you’re tackling anything bigger than a compact sedan, buy at least two cans—you’ll need the extra cleaning power."

"This product worked exactly as described. Shipping was fast, and I’d definitely purchase from this seller again. It did a great job flushing my A/C lines, evaporator, and condenser. If you’re rebuilding a car’s AC, I’d say it’s a must-have, especially if your compressor fails."

"I used this to flush out my AC lines and it worked incredibly fast. I mainly needed to remove green dye, not heavy contaminants, but for my needs, it was very effective. Just remember: you might need more than you think—so stock up."