ILSAC specs and phosphorus / ZDDP levels

[SumGuy]

Does the ILSAC specs include phosphorus or ZDDP levels, and if it does, how have these levels changed from ILSAC GF-3 (circa 2001) to GF-6A. Also wondering about seal / gasket compatibility.

I recently bought some 5W30 oil that is spec'd for GF-6A and was wondering if I might need to boost the ZDDP level for my circa 2000-2004 Chrysler 3.5L V6. Other than that, might there be any other red flag against using this type of oil in that engine?

For these oils that are GF-6 and (now) GF-7, I'm wondering if they're really cranking down on the ZDDP, and if that's a concern even if you don't have a flat-tappet (but otherwise an older) engine.

 

[RDY4WAR]

ILSAC GF-4 introduced the 800 ppm limit on phosphorus. You don't need to add more ZDDP since your engine doesn't need nor benefit from additional ZDDP. It's only a concern with flat tappet cam or race engines on the extreme end of valvetrain load such as a 500+ci V8 turning 10,000+ rpm with >1,000 lbs open spring pressure. You would only get the negative side effects of ZDDP such as worsened friction coefficient and increased acidity. (ZDDP is an acidic ester)

In applications that do need more ZDDP, you're better off to use an oil formulated with additional ZDDP as opposed to playing shadetree backyard chemist with a supplement.

 

[CharBaby]

I believe that the ILSAC GF3(>1000 ppm of ZDDP) from the early 2000’s, changed in around 2011 to GF4(~800 ppm ZDDP). I can’t remember every year that the GF# changed. I also believe the largest ZDDP/PHOS change/drop was from GF3 to GF4 and have stayed pretty steady since. Some oil brands have dropped the Z&P levels even since.

I also don’t believe that you need higher ZDDP/PHOS levels for for your engine as it already broken-in.

 

[SumGuy]

I've stumbled across this thread from a couple years ago:

C

Thread 'ILSAC GF-6A ZDDP specs'

Jul 13, 2022

So I made a discovery I’m not too pleased with. I noticed just about every oil company is touting reduced phosphorus on their main oil grades which means greater catalyst life but reduced anti wear additive. Mobil 1 is the only company that openly shares their zddp information which I highly respect them for. Looks like you have to get a high mileage oil just to have the mediocre 800ppm we’ve grown accustomed to. The regular oils now have about 760 +\- . Again it isn’t just Mobil that’s reduced it, they ALL have. I’m glad I recently switched to M1 HM, because at least it’s got the same...

• CJ Dubya
• Replies: 8
• Forum: Passenger Car Motor Oil (PCMO) - Gasoline Vehicles

From that, it's not clear to me that phos/ZDDP levels are spec'd. And yea, I get it that my engine is definately not in the catagory that needs high zddp, but I'd think I need *some* of that. I just don't want to use a house-brand GF-6A that I can't find any specs on and might have hardly any.

 

[Nessism1]

I've stumbled across this thread from a couple years ago:

C

Thread 'ILSAC GF-6A ZDDP specs'

Jul 13, 2022

So I made a discovery I’m not too pleased with. I noticed just about every oil company is touting reduced phosphorus on their main oil grades which means greater catalyst life but reduced anti wear additive. Mobil 1 is the only company that openly shares their zddp information which I highly respect them for. Looks like you have to get a high mileage oil just to have the mediocre 800ppm we’ve grown accustomed to. The regular oils now have about 760 +\- . Again it isn’t just Mobil that’s reduced it, they ALL have. I’m glad I recently switched to M1 HM, because at least it’s got the same...

• CJ Dubya
• Replies: 8
• Forum: Passenger Car Motor Oil (PCMO) - Gasoline Vehicles

From that, it's not clear to me that phos/ZDDP levels are spec'd. And yea, I get it that my engine is definately not in the catagory that needs high zddp, but I'd think I need *some* of that. I just don't want to use a house-brand GF-6A that I can't find any specs on and might have hardly any.

The oil analysis forum has lots of data that can help you find an oil that meets your sensibilities. I also like high ZDDP oils, for my motorcycle. I've torn down a number of engines that show pitting on the transmission gears, and my shade tree thinking is that ZDDP is good for engines like these.

 

[CharBaby]

^^^
I thought that too much ZDDP can actually cause corrosion/pitting?

 

[RDY4WAR]

^^^
I thought that too much ZDDP can actually cause corrosion.

Yes. Above ~1800 ppm, the corrosive wear caused by ZDDP begins to cancel out abrasive wear prevented causing overall wear rates to start increasing again. No application (outside of maybe high end race engine break-in) needs nor benefits from >1500 ppm anyway.