Here is the Lab data for the long change interval on the wife's Z24. (2.4L DOHC I-4)
Mobil 1 5W30 Oil & Bosch synthetic media filter. (K&N drop in for air)
It went 6 months and over 9500 miles.
I am posting this for all the folks that claim they "HAVE" to change the oil every 3 months or 3000 miles whichever comes first no matter what.
Starting with an excerpt from the comments from the technician:
"We didn't find much if any change in the sample compared to your last one, which is most impressive considering the oil was in use about 3300 miles more. No contaminants and air & oil filter are working exceptional."
This list will include normal wear metal amounts followed by universal averages (based on a 3k mile change btw)
Aluminum: 3 / 3
Chromium: 1 / 1
Iron: 20 / 18
Copper: 8 / 5
Lead: 3 / 4
Tin: 0 / 1
Silicon: 8 / 9
All other trace metals at 0.
Besides the "additive" elements found in the oil of course.
SUS Viscosity: 60.2 (55 low - 62 max)
Flashpoint: 390 (low > 365)
Fuel: less the .5%
Antifreeze & Water: 0
Insolubles: .3%
It looks like their previous recommendation of 10-12k is plenty safe. I think I'll stay at 5-6 months. I don't like past 4 months really but circumstances dictated a longer interval this time and now I know that's well within the safe range.
The SVT will stay at 4 months.
Matter of fact I will be changing that in the next week or two and getting my first sample on the 3L. It probably won't be a good baseline though since the engine has so few miles on it. (over 7k since rebuild and ~13k total miles) It will show how well the oil is holding up though. The 2.5L was VERY HARSH on the oil.
