Mass loss rating

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PQIA has a mass loss rating in its analysis breakdowns. If I am understanding this industry acceptable loss is 15 percent @250c for 1 hour. Sooo, The lower the rating , the better resistance to heat breakdown .

I had never paid much attention to this rating, concentrating on stuff like moly and boron. However with my recent purchase of a Chrysler with the 2.7. An engine that is known to have hot spots has lead me to look into this.
So my question is would an oil with a lower rating be better to run in an effort to avoid cooking the oil and reduce sludge formation.
Thanks
 
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Yes, ASTM D5800. And the acceptable Noack value for any oil is dependent on the license, approval or specification that the oil holds (and sometimes grade). It’s not a static value for every oil.

Lower Noack is good although it has been shown to be less of a global indicator of quality than it once was. Exactly what is left behind is also important and a gross Noack test doesn’t discriminate on this property.
 
Thanks for the clarification. In my limited browsing it seems that synthetic and lower weight oil has higher Noack values than synthetic blend and conventional oil of mid and heavier weights. This observation was somewhat surprising to me. Of course different add packs probably have some bearing on this.
Just an interesting observation.
 
Thanks for the clarification. In my limited browsing it seems that synthetic and lower weight oil has higher Noack values than synthetic blend and conventional oil of mid and heavier weights. This observation was somewhat surprising to me. Of course different add packs probably have some bearing on this.
Just an interesting observation.
Lighter base stocks can contribute to higher Noack values. Often to achieve a better winter rating. I don’t think the additive packages have much to do with it.
 
PQIA has a mass loss rating in its analysis breakdowns. If I am understanding this industry acceptable loss is 15 percent @250c for 1 hour. Sooo, The lower the rating , the better resistance to heat breakdown .
I had never paid much attention to this rating, concentrating on stuff like moly and boron. However with my recent purchase of a Chrysler with the 2.7. An engine that is known to have hot spots has lead me to look into this.
So my question is would an oil with a lower rating be better to run in an effort to avoid cooking the oil and reduce sludge formation.

After joining this forum no less than 16 years ago and members
talking about Noack literally daily, it finally catches your eye? :unsure:
Congrats.


In my limited browsing it seems that synthetic and lower weight oil has higher Noack values than synthetic blend and conventional oil of mid and heavier weights. This observation was somewhat surprising to me.

Lower weights, typically yes, since lower weights hold an increased
amount of lighter molecules with higher volatility. Fully synthetic?
Not in general, if not. Your observation seem to be to be somewhat
deceptive.
.
 
Just my limited browsing on the PQIA site led to the observation. Of course I did not look at every oil only about 25-30 that I might would use that are available in my area. Those that I looked at in general the synthetic lower weight oil had ratings in the 11-13 range. The blends and conventional oils were in the 7-9 range.
Oils included Cam 2,traveller,Castrol, Warren, super tech, Chevron,havoline, smb, Smitty's, Pennzoil.
I've never had to worry about high heat issues till now, so I always concentrated on antiwear aspects of the oil PKG.
In some ways this forum can be a detrimental to decision making. In the old days I would grab whatever was on sale. Now I have a tendency to overthink.
 
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