Most broadly compatible engine oil

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May 25, 2018
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New Zealand
Humour me. I work on quite a few cars between family, friends, and offering at cost oil changes to my community. I'm wanting to buy bulk oil drums to drive the cost down but am wanting to run my plan by a few people with a head for this stuff.
My big question is which acea spec should I get to have maximum compatibility. I'm currently leaning towards a C3 spec oil as it should be fine for old + modern petrols and diesels and doesn't seem to compromise on protection or emissions compatibility too much either way.

Am I off my rocker or would this be an acceptable solution even if not perfect?
 

lime

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New Zealand
C3 should be perfectly fine in place of A3/B3/B4 if your country uses ULSD and ultra low sulfur gasoline.
That's what I figured, it exceeds pretty much all A3/B4 specifications right?

For New Zealand, I would use a good synthetic 10W-30 with high hths (a3/b4 stuff) or 10W-40 with low Noack.
I'm a little concerned with using an A3/B4 with modern catalysts and dpfs. What would be the main protection differences between these specs and is there any reason they would be an issue with the shorter intervals I run (7,500-10,000km)?
 
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I was saying if I had to select a one-size-fits-all viscosity ... it would be 10W30 for your area. I love a good full synthetic 10W-30 high hths (preferred) or not and low Noack. 10W-30's typically have low Noack.

too many specs and different engines ... I don't think there is a universal solution for your question.

I experiment with my cars and deviate from manufacturer's spec but don't recommend it for other people's cars.
 
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lime

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I was saying if I had to select a one-size-fits-all viscosity ... it would be 10W30 for your area. I love a good full synthetic 10W-30 high hths (preferred) or not and low Noack.

too many specs and different engines ... I don't think there is a universal solution for your question.

I experiment with my cars and deviate from manufacturer's spec but don't recommend it for other people's cars.
Personally I would lean towards 5w30 FS, what are your reasons for preferring a 10w30? In my mind it's good to lower cold viscosity as much as is practical so as to limit cold start wear and oil pressure variance.

At least with C3 it has the same minimum HTHS as A3/B4. Would Noack matter as much with shorter OCIs?
 
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10W would be well within your winter temperature range. iirc it's good down to -12F. Definitely good down to 0F.
It also has less vii (vm) and typically much lower Noack than 5W-30's.
Regardless of oci, the less you burn, the better since you also mentioned cat ...

if I had to choose one oil for the rest of my life and in all our cars, it would be M1 EP 10W-30. 10W is ok for our winter temp range. I'm currently running M1 FS 0W-40 in one car but that was just an experimental thing and left-over summer time oil. Obviously I didn't need 0W for the summer but wanted a good 40 for a long trip. I could have used a 15W-40 but M1 FS had many bells and whistles and Euro this and that so I gave it a try but going back to 10W-30 EP next summer which is actually more expensive than 0W-40 FS. I just don't care for large spread oils.
 
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10W would be well within your winter temperature range. iirc it's good down to -12F. Definitely good down to 0F.
It also has less vii (vm) and typically much lower Noack than 5W-30's.
Regardless of oci, the less you burn, the better since you also mentioned cat ...

if I had to choose one oil for the rest of my life and in all our cars, it would be M1 EP 10W-30. 10W is ok for our winter temp range. c


I agree with all of this and especially the way it was said - logically and with physical/chemical reasoning included.

I differ at the M1 ___ 10w-30 step as I lean towards a different M1 flavor, but that's not as important as focusing on a narrower viscosity spread appropriate to your climate, low Noack, and robust HTHS. If you want robust oil, you start with the narrowest cold flow/full temp gap your climate tolerates on the low temperature end and your engine requires on the full-temp end (and this is NOT what's in your owner's manual, that's written for lawyers and local politics like CAFE). Most places, most engines, all over the world, it's 10w-30. Not 100%, but that's the default answer.

To butt-in on your question to him, keep in mind there is no "free lunch" anywhere - and that applies to supermarket promotions as well as oil viscosities. When you choose a 5w-30 vs. a 10w-30 where the cold start temps are not very, very low, you are sacrificing other desirable qualities in order to get that extreme cold flow. It has nothing to do with anything at normal temps, and many negatives.

Noack matters at all times - it matters any time the engine is actually running. The oil temps are not wholly uniform everywhere as a fraction of the oil is getting very hot in the rings, or under extreme pressure elsewhere. Noack matters in those spots, all the time. If you intend to never check the oil level or worry about thickening, then Noack is less important if you run a shorter OCI. There's just no free lunch, you have to think and balance things out.
 
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