MMO vs Oil Consumption.

[Gene K]

I'm not gonna lie, but I am a bit lost... Let me explain...
- Quick summary if you don't want to read from the start - Heavy oil consumption with 0w40, but when 0w40 oil is thinned with 1qt of MMO consumption goes away.
- Next oil change - straight 0w40. No consumption at first, but slowly consumption returned... Not as bad, but it is there, about 1qt/700-1000 miles.
- Next oil change - Idemitsu 0w20 (Thanks again @Egg_Head) took it on a long trip expecting even higher oil consumption, since the general consesus is that higher viscosity reduces oil consumption, while lower viscosity increases oil consumption... Or so I though. Just did over 1000 miles on Idemitsu 0w20, and the level has not moved... Still right over the full mark, as I filled it during the oil change. Lots of stop and go and spirited backroads exploration.

I mean - I'm glad that oil isn't disappearing (yet), but can't wrap my mind about an old Honda engine from the 90s preferring less viscous oil... It stopped burning when I had 0w40 duluted with MMO, and it's not burning yet with 0w20.
Will keep an eye on it and update as miles rack up.

Rings.

Thicker oil reduces consumption from the valve seals. Thinner oil reduces consumption from the rings. Add in the fresh detergents and I'm not surprised.

 

[Graham Piccinini]

Well then... Makes sense. I guess time for a piston soak. B12? MMO? Both? Anything else?

 

[ripcord]

I'd say B12, but don't expect long term results. Nothing will cure carbon-ed up rings permanently from what I've seen. It's worth a try, though. I would do an oil change afterwards and try adding a pint of MMO when the oil consumption starts up again.

Have you done a compression test?

 

[13Track38]

This thread is making me wonder if I should add MMO to my GDI engine to see if it lessens the 2qts of oil burn I have every 5k miles. If so I normally use 5W30 so what grade would be recommended with the MMO? I mostly do 2/3 spirited city driving with 1/3 freeway driving.

 

[Graham Piccinini]

This thread is making me wonder if I should add MMO to my GDI engine to see if it lessens the 2qts of oil burn I have every 5k miles. If so I normally use 5W30 so what grade would be recommended with the MMO? I mostly do 2/3 spirited city driving with 1/3 freeway driving.

0w40/5w40/10w40/0w50/5w50/10w50/15w50, either should work fine in Texas, just don't overfill it.

 

[andyd]

Toward the end of the 528e when it was barely driven, I kept the 20w50 dino in yr round. Come winter time, I just added a pint of MMO to the oil. Way less trouble than to change to 10w40 for 3 months.

 

[Peted]

I'd say B12, but don't expect long term results. Nothing will cure carbon-ed up rings permanently from what I've seen. It's worth a try, though. I would do an oil change afterwards and try adding a pint of MMO when the oil consumption starts up again.

Have you done a compression test?

Not even Kreen? (honest question) My truck burns a little bit of oil.

 

[demarpaint]

Not even Kreen? (honest question) My truck burns a little bit of oil.

That depends on what is causing the oil burning. Assuming there are no leaks I'd replace the PCV valve with an OE part before doing anything else. Now if stuck rings are causing the oil burning, Kreen or MMO might help. Worn rings, bad guides, bad stem seals, etc, it won't work. Nothing short of making the necessary repairs is going to resolve those issues. You could try STP or Lucas Oil Stabilizer for a really worn engine, it might slow consumption a bit. Good luck.