505CRO Oil System Treatment, 12 Fluid Ounces

I have a 2016 Jeep Cherokee with 330,000 miles. After amazing results using ATF Chemical 505 CRF Fuel System Treatment (see separate review), I ordered this ATF Chemical 505 CRO Oil System Treatment. I believe my results are of particular interest because I did not perform the treatment by adding the product to dirty old oil, as you would right before an oil change, but I added the product to fresh clean oil right after an oil and filter change. Wait till you see what happened. The instructions say to add the product to your engine's oil, run the engine at "high idle" (some mechanics say @ 2,000 RPM) for 10 minutes or more, then drain the treated oil, remove the oil filter and install a new filter and new oil. However, what I did was last night I added the product to the fresh oil that was in my car, ran the engine at regular idle speed (say 750 RPM) for 10 minutes, turned off the engine and let it sit overnight. This morning I started the engine and moderately drove the car (2,000 RPM max) for 40 minutes, parked the car and let it sit for a few hours, then drained the oil. I was very curious to see what the oil looked like when I drained it. Would it look like the brand new oil that I had just put in the car? The answer is an emphatic NO - the oil was PITCH BLACK - it looked like old oil coming from an engine that was overdue for an oil change. In my opinion this stuff does what it was designed to do. It cleaned out the built-up carbon deposits internal of my engine. After installing a new filter and new oil I drove the car today as normal for about 90 minutes around town and highway. It is probably too soon to tell but I think the engine runs smoother and quieter. I will now be using these products on all my vehicles (5 cars/trucks, 4 motorcycles) and recommending this product to everyone. I am SO glad I found out about these products from a mechanic on YouTube who says these are "products your mechanic does not want you to know about" and that they will "make your vehicle last 3x longer". I have no doubt this is so. Easy to use. Does as advertised. Worth every penny.

This works well! I have an '07 honda accord 2.4L LX with 190k, and it had started burning oil like most cars do. I was pissed because I've had the car 13 yrs., and religiously changed the oil with the best synthetic and never beat on it. I tried the top end cleaner routine where you remove the plugs and directly pour the cleaner into the spark plug holes,(ac-delco Top End cleaner), and it did help. The theory being your ring and cylinders aren't worn out, rather, carbon and other crud has built up in the ring valleys and around them, seizing them up, letting oil get by. I ran this at 2200 rpm for 15 min., then drained. It was a weird khaki green and brown color. Filled it with castrol high- mileage synthetic and new filter. Motor definitely quieter and smoother. Much better acceleration and power. Definitely worth the money!

Seems to work great. Notice a difference after a hour of running engine. Next morning engine started and idled much smoother and a little higher on RPM. better throttle response for sure. Expensive but most likely worth it.

Hey, I've tried many a thing, and few were decent, but this stuff, this brand, actually works!The fuel additive was a game changer, so i tried this oil additive.Another game changer! The car runs better, it's more spirited.Tip of the hat to Scotty Kilmer for showcasing this company - Scotty says it like it is, and my car thanks him.If you have an older vehicle, this is where you give the engine a face lift - my car runs "years younger", and I've had it for nearly 10 years, and it's 25 years old! I know what I'm talking about.I'm going to repeat the oil treatment later in the summer before an oil change and really clean my car's oil system. One treatment has been very effective, and I could coast, but with a car this old, there is likely a bit more buildup in the system.

I bought this for a Hyundai Tucson which is known to consume oil and cause carbon buildup regularly. In October 2024 I went to Kia for their $700 engine clean out which did make it better but was still stuttering and consuming oil. I bought this in January 2025 and have drove the car 2,000 miles. The car has not hardly consumed any oil which the dealership said could happen with their product. This tells me this product has worked well cleaning the deposit buildup and the car has since ran smoothly. I can’t say it’s increased the MPGs much but it definitely worked. I also used it on my 2021 John Deere mower which was having a rough idle. It has also worked on it stopping it from revving while idling. The only problem I have with this product is the cap was broken from shipping and a couple ounces have seeped out. The company wouldn’t let me return it which was frustrating to pay so much per ounce and lose some of it. But still I highly recommend it and I will use again.

Literally miracle juice. My noisy engine was burning oil, but now it sounds like it did 60,000 miles ago! Will absolutely be using this again. The idle RPMs are finally back to normal!I was looking at other cleaners to add to my oil but all of them required me to run them in the oil for ~100 miles. But with this stuff it was just 10 minutes before I changed my oil. The only annoying part was having to keep my foot on the pedal and laser focused on the RPMs for 10 minutes. But suuuuper worth it.

Why did you pick this product vs others?:I bought this after watching Scotty Kilmer on YouTube. I have a 2006 Hummer H3 with 250,000 miles and figured a good system clean couldn't hurt. I was honestly surprised at how well this stuff worked. There was a noticeable performance improvement which I've found to be rare for most fuel cleaning products.This stuff does exactly what it claims to.

Great product, but a little pricey for such a small can. Use a funnel to put this into your gas tank.