I just did this with my CR-V which has been consuming oil for the last 50K miles or so. I've read it is common for the oil control rings to get stuck on GDI engines. Anyway, pulled the plugs, hit the cylinders with a couple shots of PB Blaster. Waited a bit then poured a couple ounces of Chemtool B-12 in each cylinder. Waited until it all drained. This took anywhere from a couple of hours to roughly 8 for one cylinder. Followed this up with a couple ounces of Maxlife ATF in each cylinder and let soak overnight. One cylinder drained on its own. I had to suction the other 3. Turned it over a few times with the plugs out (lots of carbon bits on the towel covering the holes). Installed the plugs, then cranked it up and let idle for 15 minutes (some white smoke), then changed oil and filter. Oil was f'n nasty, pitch black. I've got ~100 miles on it post piston soak and it feels like a new car. Acceleration is like I remember. Time will tell if the oil consumption is resolved. Crossing my fingers...

I researched the hell out of it. B-12 Chemtool will F your engine up if you do it wrong, but it can be very effective if you do it right. I had read enough posts where people said MMO didn't do shi*. It's still an option though. Lot's of different opinions on the subject...

I own 2 CR-Vs, a 2012 and a 2016. My 2016 got so bad that my 2012 with ~235K miles felt stronger. It is much better now. I'm just not used to Honda's having oil consumption problems.

Roughly 2K miles since the procedure and oil has stayed at essentially the same spot on the dipstick. It would have been at the bottom dot within 1k miles previously. I also went up a weight in oil (5W-30).

I'm actually pretty surprised. I was expecting to still have some consumption and hoping just not as much. Oil level is really right about where it was when I did the oil change. If I were to do it all again, I'd probably try some of this fancy Valvoline oil, specifically designed to free up stuck piston rings. It ain't exactly cheap, but is cheaper than ruining your engine...

https://volvo.cummins.com/file/1380

I've read a few experiences like that using diesel, ATF, MMO, and a few others.

@4K miles and the oil is just a smidge below the top dot on the dipstick. I put the rest of the 5 qt jug in before a recent long trip. 4.6 quarts is considered full, but that doesn't put the oil at the top dot. I'd estimate the engine has consumed a fifth of a quart. I'm very happy with these results after 4K miles.

I'm planning on putting another 1K miles on it, then changing the oil (and probably the filter) again.

There are some less risky options you could try, but I'm definitely pleased with how this turned out. I'm tempted to go back to 0w-20 for the next change just to see if it starts consuming again. Based on everything I read, the big gotchas are you don't want to have any liquid in the cylinders when you try to start it up (potential for hydrolock) and the last thing you pour in shouldn't be B12 since it isn't a lubricant.

I've seen folks concerned about hard carbon deposits breaking loose and damaging the engine. The bits that came out when I turned it over a few times had the consistency of clay.

Had to delay the oil change to ~6500 miles. I've got one jug of 0w-20 left, so I've switched back to that just to see if the oil consumption gets bad again.

I topped off once with the remainder of the 5 quart jug and that was it. This is where it was right before I changed it. It's a huge improvement.

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