AEHaas,
Depends on specifics.
I do 3000 mile OCI on a Porsche 911 with 176K miles on it.
Why ? Castrol GTX 20W50 usually cost me $1-1.50. 12 qt capacity so thats $12-18 + filter. It consumes 2 qt's in 2000 miles (that's better than most 911's ~600mi/qt). Usage accelerates as oil gets dirty in this thing. It would probably consume 5-6 qt during a 5000 mile OCI. It does not make sense to to me to keep adding new oil to the old. Consumption is due to brass valve guides on this application.
Next I don't want to price out a rebuilt engine. I'll guess maybe $10K installed. Ok, maybe I can get just heads rebuilt, $4K. That buys a lot of oil !
Finally I believe the consumption accelerates with GTX due to sheer down and ZDDP depletion. I don't really know. The engine sounds better with fresh oil when swapping out GTX.
BTW, during the first 120K I did 7.5K OCI figuring the 12 qt capacity would help (Porsche recommends 15K OCI). At 17K miles it consumed 2qt/3500 miles. I now know that was too long as oil consumption increased.
At 3000 mile OCI over the last 55K miles consumption has been stable. That's why I do 3000 mile OCI, I wish I had done this from day one....
Depends on specifics.
I do 3000 mile OCI on a Porsche 911 with 176K miles on it.
Why ? Castrol GTX 20W50 usually cost me $1-1.50. 12 qt capacity so thats $12-18 + filter. It consumes 2 qt's in 2000 miles (that's better than most 911's ~600mi/qt). Usage accelerates as oil gets dirty in this thing. It would probably consume 5-6 qt during a 5000 mile OCI. It does not make sense to to me to keep adding new oil to the old. Consumption is due to brass valve guides on this application.
Next I don't want to price out a rebuilt engine. I'll guess maybe $10K installed. Ok, maybe I can get just heads rebuilt, $4K. That buys a lot of oil !
Finally I believe the consumption accelerates with GTX due to sheer down and ZDDP depletion. I don't really know. The engine sounds better with fresh oil when swapping out GTX.
BTW, during the first 120K I did 7.5K OCI figuring the 12 qt capacity would help (Porsche recommends 15K OCI). At 17K miles it consumed 2qt/3500 miles. I now know that was too long as oil consumption increased.
At 3000 mile OCI over the last 55K miles consumption has been stable. That's why I do 3000 mile OCI, I wish I had done this from day one....