No SP rating for high Phosphorus Diesel xW40 Motor Oil

[Snagglefoot]

I the past some xW40 diesel motor oils with Phosphorus levels greater than 800 ppm have still been given a SN rating. This apparently was a compromise given by API when the SN rating came out, limiting Phosphorus to 800 ppm. From what I read, the API have put their foot down and this will no longer be the case. If it has more than 800 ppm Phosphorus, it will not get an SP rating. This is supposedly effective, May 1, 2021.

If I interpreted that incorrectly, chime in. By the way, regarding GF-5, it’s not actually obsolete until May 1, 2021, so sellers are under no obligation to provide GF-6 until then, even though most manufacturers are putting it out now. For instance, Mobil said they plan to have all the GF-6 products labelled as such by the end of this summer.

 

[loneryder]

Why do you want an SP rating on a diesel motor oil??

 

[Snagglefoot]

Why do you want an SP rating on a diesel motor oil??

It relates back to SN. A lot of people purchased and still purchase xW40 motor oil for their gasoline engines, mostly because they like the high zinc and phosphorus it usually contains as ZDDP, an anti-wear additive. The manufacturers insisted their diesel motor oil should be acceptable for gas engines except for that issue about phosphorus being bad for catalytic converters. Many people say it doesn’t matter if the engine does not burn oil. The API disagrees with that. They don’t want high phosphorus motor oil in gasoline engines. Hence, no further approvals for it.

 

[Snagglefoot]

Here is where it says Mobil Diesel Truck 5w40 meets the requirements of API SN even though though the phosphorus is 1100 ppm, well over the 800 ppm limit. It was a special allowance for manufacturers of XW40 diesel motor oil.

 

[OVERKILL]

Here is where it says Mobil Diesel Truck 5w40 meets API SN even though though the phosphorus is 1100 ppm, well over the 800 ppm limit. It was a special allowance for manufacturers of XW40 diesel motor oil.

View attachment 25627

Doesn't just apply to diesel engine oils, look at the Euro 0w-40's.

 

[SR5]

I find this a bit confusing myself. It use to be that the 800 ppm Phos limit applied to ILSAC grades (30 and below) and that 40 grades and above had a higher 1200ppm Phos limit. To claim API SN.

In a recent thread there is a comparison of Rotella 15W40 and Delvac 15W40

Rotella T4 15W40 Vs Mobil Delvac 1300 Super

Not sure if this has been posted before, but it's some OEM HDEO engine oil tests applied to Shell Rotella T4 15W40 and Mobil Delvac 1300 Super 15W40. Specifically the Volvo T-13 oxidation test, and some similar API CK-4 tests. It is from a Shell web page. It's interesting to see some real data...

www.bobistheoilguy.com

The Delvac claims API CK-4 & SN with just under 800 ppm Phos.
The Rotella claims just CK-4 (no SN) and has almost 1000 ppm Phos.

I think things have changed, but I’m not sure if it’s in the API rules or via some sort of self regulation agreement. Certainly the Euro 40 grade oils VOA/UOAs I’ve seen recently still show about 1000 ppm Phos with A3/B4 and SN rating, but I’m not sure how up to date these are.

BTW the thread I started, linked to above, suggest (to me at leas) that ZDDP levels correlate to control of oxidative thickening at the bitter end of a long oil change interval.

 

[Snagglefoot]

What I gather is when SP kicks in next May, they will not have any special designation for XW40. The API had a vote and they will no longer support a designation for oils above 800 ppm Phosphate. At least that’s how I interpret it.