Syntec 5W-30 3.7k miles / 2008 Subaru Forester X 2.5L 144k miles

[Soobs]

Hello all,

This is just a quick check-up report on my '08 Subaru Forester.

Oil in use: 6 months
Conditions: 2/3rds city driving

Removed:
Syntec Full Synthetic 5W-30 (3.7k miles)
OEM 16546AA020 engine air filter (10.5k miles)
O'Reilly's MicroGard Select MSL57712 oil filter (3.7k miles)
OEM 72880SA000 Cabin Air Filter (10.5k miles)

Installed:
Mobil 1 High Mileage Full Synthetic 5W-30
OEM 16546AA020 engine air filter
O'Reilly's MicroGard MGL57712 oil filter
TYC 800075P Cabin Air Filter

 

[SubieRubyRoo]

That oil had plenty of life left in it, but it looks like you need to check your air filter and intake tract.

 

[Soobs]

That oil had plenty of life left in it, but it looks like you need to check your air filter and intake tract.

Sure, but I'm not interested in extended oil change intervals which is also why I don't test TBN. About every 3,750mi (manufacturer severe service schedule) is cheap insurance for me on this old gal. As mentioned in the post I replaced the engine air filter. It was very dirty. All connections appear sealed and tight so I'm not really worried about the slightly elevated silicon, especially since other wear levels don't show compelling evidence of a contaminate. Truckin' right along.

 

[SubieRubyRoo]

Sure, but I'm not interested in extended oil change intervals which is also why I don't test TBN. About every 3,750mi (manufacturer severe service schedule) is cheap insurance for me on this old gal. As mentioned in the post I replaced the engine air filter. It was very dirty. All connections appear sealed and tight so I'm not really worried about the slightly elevated silicon, especially since other wear levels don't show compelling evidence of a contaminate. Truckin' right along.

10.5 k on an air filter really isn’t much, and may actually be why you saw the elevated silicon. Air filters actually do get more efficient over time, and more frequent changes put you at risk for errant stuff getting into the intake tract and/or not getting stuff sealed. 20k is still plenty safe; there are folks here who have gone 50k+ and never seen elevated silicon. Just a thought.

 

[Soobs]

10.5 k on an air filter really isn’t much, and may actually be why you saw the elevated silicon. Air filters actually do get more efficient over time, and more frequent changes put you at risk for errant stuff getting into the intake tract and/or not getting stuff sealed. 20k is still plenty safe; there are folks here who have gone 50k+ and never seen elevated silicon. Just a thought.

Yep, I understand the filtration mechanics and no argument there. The manual says every 30k miles or “replace sooner in extreme or dusty condition.” I changed it at a shorter interval due to certain conditions I operated in mostly over the summer and how dark it was holding against the sun. Could it have gone longer? Sure. But it’ll be fine. Moreover, previous UOA silicon measurements were very low with short interval air filtration changes as well. I’m just not concerned with it on a single report with no other elevated wear metrics.