Group 3 + GTL vs Group 3 + PAO

[Carlostrece]

Comparing two high mileage oils that have equal additives and viscosity...

One oil is 90% regular Group 3, 10% PAO

The other oil is 25% regular Group 3, 75% GTL

What do those base oils suggest performance will be?

Would the oil with PAO be better at cleaning?

Would the oil with GTL be better for reducing/preventing leaks?

Would one be better for extended OCI?

Anything else?

 

[kschachn]

This is worse than trying to predict future performance through a PDS of typical values or a VOA.

And, let me guess - you're trying to make a case for your favorite brand of Havoline vs. Valvoline?

Lots of unfounded presuppositions here. Base oil is essentially unimportant for leaks, especially for a predominately Group III oil or even for a majority Group IV that is properly additized, which they all have been for 50 years.

GTL is Group III. The finished product is what matters. And how do you know what the additives are? What blender lists their additives?

 

[rumcapital23]

i'm not very smart but if i had to give you an answer for all the questions above:

ignore the marketing on the high mileage bottles and run Mobil 1 0W-40 , you'll sleep like a king at night

 

[Prison_Mike]

Unless it needs cleaning, I'd just opt for the GTL. It's an extremely clean base oil as is and doesn't seem to need the additive boost that other oils need.

 

[Tkonrr]

My understanding is that 3+ is only mildly inferior in performance to group 4. There may not be much of any difference in performance between your two choices.

 

[JAG]

I think it’s close to impossible to answer many of those questions, partly because there is considerable variability in properties within regular Group III oils, within GTL oils, and especially PAO oils. Even with specific oils identified, unless the person is an experienced tribologist or the right kind of industry-insider, it would still be difficult to say much beyond viscometrics and volatility of the base oil mix.

I can say that PAO is the least capable of cleaning since it is the least polar. PAO has excellent oxidative and thermal stability (good at staying clean). GTL and a similar viscosity PAO will have similar effects on seals, with PAO having slightly more shrinking effect. Other additives will also affect the seals which could overwhelm the effects of the minor base oil differences.

Here are two good base oil articles:
https://www.infineuminsight.com/media/1814/3-lubricant-base-stocks-na.pdf
https://www.stle.org/files/TLTArchives/2022/09_September/Cover_Story.aspx

 

[Brian123]

One oil is 90% regular Group 3, 10% PAO

Sounds like a few Oils!

The other oil is 25% regular Group 3, 75% GTL

I want this Oil!

What do those base oils suggest performance will be?

Nothing!

Would the oil with PAO be better at cleaning?

It might be better at doing something else!

Would the oil with GTL be better for reducing/preventing leaks?

Maybe or maybe Not!

Would one be better for extended OCI?

What mileage are you talking about as far as what you consider to be an extended OCI?

 

[Sam_Julier]

This thread has run its course. Lock time.