Getting ready for my 1st oil change and seeing a lot of information on this and other forums with no real conclusion I decided to do a little research to see what I could find about engine oil for my 13 XF 5. SC. FYI I still have 6 months of factory warranty and 2 more years of CPO.

I started by getting copies of the following FoMoCo oils spec's, WSS-M2C925A and there are very few oils that meet this spec and the new WSS-M2C945A.

925A (activated 08/2002 and revised 06/2004)

Performance Specification - "Shall meet all the requirements of the ILSAC Minimum Performance Standard for Passenger Car Engine Oils GF-3" "ACEA European Oil Sequences A1-02 and B1-02" and the following additional Ford Requirements (statements about oxidation stability and fuel effeciency)."

945A (activated 07/2010 and revised 08/2013)

Performance Specification - "Shall meet all the requirements of the "ILSAC GF-5 Minimum Perfornace Standard for Passenger Care Engine Oils" Plus the following (statements about ASTM testing standards"

Basically 925A is a ILSAC GF-3 and 945A is a ILSAC GF-5 engine oil.

According to the American Petroleum Institute (API) GF-3 and GF-4 are obsoltes and should be replaced by GF-5, http://www.api.org/~/media/files/cer...glish_2013.pdf

I also found the following article that includes a discussion with Dr. Bob Sutherland, chief Pennzoil scientist at Shell Global Solutions and one of the world's leading motor oil chemists. He makes the following statement in the article "The final key stipulation for all GF-5 oil is that it be backward compatible. As Dr. Sutherland stated, "This is a core issue, since we don't want owners of older vehicles to be unable to use the new GF-5 oils. We therefore must ensure that all of the requirements put into GF-5 are equal to or superior to GF-4, GF-3, GF-2 and so on, so that it's always backward compatible. This way, even if your owner manual says to use GF-4 oil, you're safe to go up to the next category, just like you're safe to go up from conventional oil to a synthetic blend to full synthetic oil. You never want to go down in spec, so if you buy a new car with an engine built specifically for GF-5 oil, don't run GF-4 in it." Here is the link to the article ILSAC GF-5 Motor Oil Standard - A Smarter Motor Oil - Modified Magazine

Based on this and Federal Law, I am going to use a full synthetic that meets ILSAC GF-5 and not worry about using that special snake oil that Jaguar is recommending. By the way ILSAC GF-6 is under development.

 

I thought the 5.0 oil had been covered in depth but not having one paid not a lot of attention - tried Search / reading old threads?

As I recall, it's a fussy engine and best to avoid the oils used in such as mine.

 

The WSS-M2C945A spec is not applicable to this vehicle.

 

I would like to know if you have in fact been using a full synthetic that meets the ILSAC GF-5, as opposed to the Castrol Professional OE bullshit (meeting Ford WSS-M2C925A). Any engine problems? I am currently trying to decide if I absolutely need the Ford WSS-M2C925A for my next oil change or if any other good fully synthetic will suffice.

 

I have had no issues. I used Castrol Edge Full Synthetic w/Titanium, meets ILSAC GF-5.

 

Sorry to pry, but how many miles have you driven using the Castrol Edge Full Synthetic? I want to start using that same oil instead of the Castrol Professional OE, but some people swear that you need to use the "special Ford WSS-M2C925A" otherwise you will damage the engine.

 

I have about 5K with the Edge Full Synthetic. I obtained copies of Ford's oil specifications M2C925A and M2C945A. The really only differences were ILSAC GF3 to ILSAC GF5. ILSAC GF3 is obsolete and the GF5 is backwards compatible, meaning it meets or exceeds GF3 specs.

 

Ah, thank you for that information. I had tried to research whether the 945A spec replaced the 925A spec but came up with nothing. In any case, your experience leads me to believe that the Castrol Professional OE is unnecessary.

 

Although the 945 spec is indeed a newer spec than the 925, it does NOT replace the 925 which is in fact a slightly more demanding spec. This being said, for the average user it really won't matter. Any full synthetic 5w-20 from a major refiner should serve very well unless the vehicle is subjected to very heavy service (frequent track use, hard acceleration, or sustained high revs, taxi service, etc.). For what it's worth the two Jaguar dealers in my area (same ownership) switched from the special Castrol to Valvoline over two years ago. The 925 spec is not only met by the special Castrol. Several other brands have at least one oil in their family which meets it, although this is not always stated on the container. As an example Mobil One is a brand with a family of several different full synthetic oils. Most do not meet the 925 spec but they have one that does, or at least they once did.

 

Does freeway driving with some hard accelerations count as "heavy service" in your opinion. (I'm only partly joking). Thank you for sharing this information and your opinion!

 

925 became obsolete when ILSAC GF3 was replaced by GF5. Wonder how 925 is more demanding when 945 references ILSAC GF5. The 5.0L SC would benefit from the GF5 improved deposit and sludge prevention. GF5 is still the current version released from ILSAC.
ILSAC GF-5Introduced in October 2010 for 2011 and older vehicles, designed to provide improved high temperature deposit protection for pistons and turbochargers, more stringent sludge control, improved fuel economy, enhanced emission control system compatibility, seal compatibility, and protection of engines operating on ethanol-containing fuels up to E85.