Originally Posted by BHopkins
Originally Posted by bluesubie
The Subaru Idemitsu factory fill has higher moly and ZDDP than the dealer service fill. Odd thing is that sometimes Subaru factory fills show high ZDDP and sometimes they do not.
Can you provide a source for that information?
When I bought my Outback, I specifically inquired to Subaru on this subject, wanting to know how long I should wait to change the factory fill motor oil. Subaru replied that as the factory fill was standard synthetic 0W-20 motor oil, there was no need for any particular oil change interval for the factory fill. They further stated that if I wanted, I could change the oil early but there was no reason to change it before the recommended oci.
Further research told me that almost none of the manufacturers fill their engines with "break-in" oil any longer, as it really was not necessary with modern engines and today's engine assembly practices. So I'm pretty skeptical when I see claims that any OEM still puts "break-in" oil in an engine.
At the very least just do a google search and look for uoa's on the factory fill. Here's one of the first that popped up for me (on an STI):
https://www.bobistheoilguy.com/forums/ubbthreads.php/topics/4517965/New_18_STI_Factory_fill_UOA_1,
And an H6 Outback:
https://www.bobistheoilguy.com/foru...utback-3-6-5w-30-factory-fill-3310-miles
Lots more are out there. Looking through NASIOC WRX FA20DIT uoa's you can find FF uoa's with both high and low ZDDP. Perhaps they were trying different formulas, I don't know.
And while this info is dated, this is an excerpt from an email from ILAC sent to another member here that was inquiring about the older API SM Subaru oil because it had high moly (surprised he hasn't commented yet):
Quote
You ask some very good questions which I will answer in "generalities". First, just so you know where the information is coming from, Idemitsu supplies most of the OEM's for both Factory fill and service fill. ...
OEMs specify Moly in their factory fill formulations to increase fuel economy during the initial period.
In general a factory fill formula will be more robust in the additive treatments etc. This is done for a variety of reasons which I will not go in to here.
Some of the service fill formulations also contained molybdenum however, with the transition to the ILSAC GF-5 specification, most 0W-20 service fill 0W-20 formulations now do not have Moly. That being said, you are always safest following the OEMs recommendations. All service fill OE formulas that we supply have been submitted to a full battery of tests at that respective OEM's R&D facilities in Japan and have been approved.
The only way I'll believe otherwise is if every FF uoa posted shows lower ZDDP or if there is a tech document posted about it.