an extended OCI on full synthetic?
The Sienna in my sig now has 142K. I will put it on 10K OCIs with synthetic (filter and oil are already in my garage), but I want to key it to the odometer (in other words, I start a 10K OCI at 150K, then change it at 160K, etc.). I would just put in synthetic now, for an 8K OCI, except for one thing—I’m thinking that the engine might have lots of gunk in it, because it was not well maintained the first 120K miles. I looked on my spreadsheet and the average for that time was a conventional oil change every 8000 miles. Since then, I have changed it every 4000-5000 miles, with conventional (and one run with a synthetic blend). Throughout the minivan’s life, most of this driving has been city, short trips (5-10 miles per trip), with occasional romps on the freeway. The OEM recommendation was 5K conventional, but they have since added 10K with synthetic as being OK.
So what would be best for this engine---to just go on extended OCIs with full synthetic now, for 8000 and then 10,000 mile OCIs? Or would it be best to run something like MaxLife for a couple of short OCIs until it hits 150K? I’m wondering if all the buildup of grime during that first 120K miles would cause me any problems if I went to an extended OCI with an oil designed for one, with lots of cleaning agents to dislodge it (and last for a good 10K OCI).
FWIW, I brought it over to my trusted mechanic, and he said since there is no smoke coming out the tailpipe when I start it, and he looked at the dipstick and saw there was no grime or grit at all, that there was no reason to think I had a sludge problem.
The Sienna in my sig now has 142K. I will put it on 10K OCIs with synthetic (filter and oil are already in my garage), but I want to key it to the odometer (in other words, I start a 10K OCI at 150K, then change it at 160K, etc.). I would just put in synthetic now, for an 8K OCI, except for one thing—I’m thinking that the engine might have lots of gunk in it, because it was not well maintained the first 120K miles. I looked on my spreadsheet and the average for that time was a conventional oil change every 8000 miles. Since then, I have changed it every 4000-5000 miles, with conventional (and one run with a synthetic blend). Throughout the minivan’s life, most of this driving has been city, short trips (5-10 miles per trip), with occasional romps on the freeway. The OEM recommendation was 5K conventional, but they have since added 10K with synthetic as being OK.
So what would be best for this engine---to just go on extended OCIs with full synthetic now, for 8000 and then 10,000 mile OCIs? Or would it be best to run something like MaxLife for a couple of short OCIs until it hits 150K? I’m wondering if all the buildup of grime during that first 120K miles would cause me any problems if I went to an extended OCI with an oil designed for one, with lots of cleaning agents to dislodge it (and last for a good 10K OCI).
FWIW, I brought it over to my trusted mechanic, and he said since there is no smoke coming out the tailpipe when I start it, and he looked at the dipstick and saw there was no grime or grit at all, that there was no reason to think I had a sludge problem.
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