This goes against every lube engineer I've ever herd of on this subject. Tell that to a Merc.engineer with their 13,000 mile OCI.
Originally Posted By: Art_Vandelay
Interesting to say the least. What do the experienced people on here say?
...using synthetic does NOTHING to allow a longer drain interval. Synthetic has the same amounts of ZDP, same problem with fuel and water contamination, same problems with soot, same problem with acid buildup. All reasons why synthetic oil does NOT allow longer drain intervals.