Your Max OCI (in months) With Synthetic Oils ?

Providing you do not reach your preferred OCI mileage first (i.e. 5K , 7.5K , etc.) what is the max length of time (in months) you establish as part of your OCI routine with synthetic oils ? For most of us - it's usually a mix of highway and suburban driving with the occasional stop & go city trip thrown in here and there . Owners Manuals state either 6 months or 12 months max but of course there may be other variables such as whether you drive a GDI engine vehicle or not ? Since my main vehicle has a GDI engine , by 6 months the oil becomes fairly dirty (soot) and is starting to become a bit fragrant (fuel dilution) ... So , what is your max length of time you establish as part of your OCI routine with synthetic oils ?
Six
 
OP here : I just hit the 6-month mark with 2,635 miles on the oil (Valvoline Advanced 5W30) with a ST 10K mile #9688 oil filter . 2017 Hyundai Sonata 2.4L GDI (non-turbo) . Oil was black with soot and smelled of fuel in a well-kept engine since new with 4K mile / 6 month OCI's . PCV valve was changed 3K miles ago at 41K miles (Original PCV valve was still in good shape - but low cost and easy to change on this engine so I figured why not ?) Most trips were 15 miles or less to work , gym and running errands , all in the suburbs with an occasional (monthly) interstate run at high speeds for 30+ minutes. I could never see an OCI longer than 6 months with my current driving routine with this vehicle (no matter the oil) and next OCI time will be dropped back to 4 ~ 5 months while monitoring the oil. Perhaps if I had a daily commute of 50 miles non - stop on an interstate at higher speeds my oil may have been in better shape at the 6-month mark , it's hard to say ? On my new oil & filter change today I used Valvoline 5W30 EP and went back to my preferred Fram Ultra #9688 oil filter. The ST #9688 oil filter I just changed out with its hard , beveled rubber gasket had leaked oil around the edges of the oil filter even though it was tight and the metal engine mating surface was spotless and always cleaned any way prior to installing a new oil filter. Lastly , make up oil over the last OCI was about 3/4th of a quart . Best case , this write up will help others with a similar Theta II 2.4L GDI engine - worse case BITOG followers can see what type of OCI's other folks are achieving here with different vehicle makes and engines .
 
OP here : I just hit the 6-month mark with 2,635 miles on the oil (Valvoline Advanced 5W30) with a ST 10K mile #9688 oil filter . 2017 Hyundai Sonata 2.4L GDI (non-turbo) . Oil was black with soot and smelled of fuel in a well-kept engine since new with 4K mile / 6 month OCI's ...
Same issue with my for Ford D.I with most changes under 2500 miles 4-6 months.

This Tech is not ready for prime time ( from many manufacturers implementations )
 
OP here : I just hit the 6-month mark with 2,635 miles on the oil (Valvoline Advanced 5W30) with a ST 10K mile #9688 oil filter . 2017 Hyundai Sonata 2.4L GDI (non-turbo) . Oil was black with soot and smelled of fuel in a well-kept engine since new with 4K mile / 6 month OCI's . PCV valve was changed 3K miles ago at 41K miles (Original PCV valve was still in good shape - but low cost and easy to change on this engine so I figured why not ?) Most trips were 15 miles or less to work , gym and running errands , all in the suburbs with an occasional (monthly) interstate run at high speeds for 30+ minutes. I could never see an OCI longer than 6 months with my current driving routine with this vehicle (no matter the oil) and next OCI time will be dropped back to 4 ~ 5 months while monitoring the oil. Perhaps if I had a daily commute of 50 miles non - stop on an interstate at higher speeds my oil may have been in better shape at the 6-month mark , it's hard to say ? On my new oil & filter change today I used Valvoline 5W30 EP and went back to my preferred Fram Ultra #9688 oil filter. The ST #9688 oil filter I just changed out with its hard , beveled rubber gasket had leaked oil around the edges of the oil filter even though it was tight and the metal engine mating surface was spotless and always cleaned any way prior to installing a new oil filter. Lastly , make up oil over the last OCI was about 3/4th of a quart . Best case , this write up will help others with a similar Theta II 2.4L GDI engine - worse case BITOG followers can see what type of OCI's other folks are achieving here with different vehicle makes and engines .
Have you ever reached to 3k miles under 3 months? How was the oil quality compared to this 6 month?
 
I also go by mileage. Usually 5000 miles on the Acura in signature but between 3 and 5 thousand on all other vehicles in the stable. Most are short tripped 70% of the time. In town trips or a little drive through the State Park close to my house here and there. Work is 12.8 miles one way and 90% I take the Acura.
 
Another consideration is time on the oil - since Hyundai includes time of oil in use I'm looking to change the oil at the 150 hr. ~ 200 hr. mark .
 
Synthetic does not matter, some engines like Honda 2.0t dilute oil with gas, so you need to change oil sooner, like 3k miles
 
I've run Mobil 1, and PU and others for over 2 years in vehicles that weren't driven often with no adverse effects.
 
Several years normally but given the usuage of the truck I have changed tactics to twice a year but with cheap oil despite the light number of miles (under 1000 a year)
 
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