skyship, thanks for replying
Originally Posted By: skyship
If you spend a lot of time in traffic at low power it does tend to cause fuel contamination of the oil
I think, this is the issue, because my everyday morning trip lasts for 20min and 3-4 miles, but the engine's temperature becomes 170-180F by the end of the trip only. There might be some long trips at the evening and holidays.
Average fuel consumption was at 21 mpg during workweek and 40 mpg - holidays
Originally Posted By: skyship
When you take a sample make sure you drive for a least 30 minutes otherwise that can also cause an increase in the fuel reading.
I took the sample after some city driving, but the temperature of the coolant was about 188-190F for 10-15 min
Originally Posted By: skyship
The Iron figure is a tad high for the miles, but you would have to compare it with average UOA results from other engines of the same type as some engines shed more Fe than others. The example you listed is not a good one as the engine concerned seems to be in poor condition.
I've found common Fe average for pkw and it's about 100 mg/kg. But it would be great to find figures for my engine
Originally Posted By: skyship
Extending the OCI with the fuel contamination figure you have might not be such a good idea, although you can leave the oil filter in place for the full manufacturers recommended interval as it won't block the filter.
The standart OCI I use is about 6000-7000 miles. But this time it was aprox. 8000 miles. This 8km sample was sent to lab 3 weeks ago.