Really cool video about how synthetic vs conventional oil effects engines over 500,000 miles

[KayaPayaPigDog]

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[Just sum guy]

Really interesting to see! Thanks for posting that.

 

[KayaPayaPigDog]

Really interesting to see! Thanks for posting that.

for sure, i think the most impressive thing was the lack of carbon buildup on most of the valves in the full synthetic motor!

 

[Just sum guy]

for sure, i think the most impressive thing was the lack of carbon buildup on most of the valves in the full synthetic motor!

Not to mention that the conventional oil motor had rings frozen on. Just confirms what we've all been thinking the last several years.

 

[entoptics]

Cool demonstration, though perhaps a little "unfair" in the real world, since the change interval was 10,000 miles. In my circles, it's accepted that conventionals and blends should have shorter interval changes than full synthetic.

Would love to have seen 3 engines in the test.

10K changes for both synthetic and conventional, as well as a 3rd engine with conventional that was changed more frequently, such that the cost of the oil+filters was exactly the same.

I personally spring for the full synthetic in my rigs, but it would be cool to know which is "cheaper in the long run", or if the conventional could even compete in wear and varnish no matter how often you changed it.

 

[superj]

yeah, no way i would go 10k on conventional oil. that is kind of unfair in the comparison since everyone knows to change dino oil at 3k

 

[stemplar]

yeah, no way i would go 10k on conventional oil. that is kind of unfair in the comparison since everyone knows to change dino oil at 3k

I disagree with the notion that the test was unfair, especially for the reason quoted here. Both Valvoline synthetic and conventional 5w30 oils meet the Ford spec for our engines, so I seriously doubt most folks ask if the oil that a mechanic used was conventional and then adjust the factory-specified change interval to 3k or even 5k. I think it's far more likely that most folks just wait for their dashboard to tell them to change their oil.

Sure, many of us here are uncomfortable going 10k on conventional, fewer are uncomfortable going 10k on synthetic, and fewer yet get TBN numbers from drain samples to help determine when their oil actually needs to be changed, rather than going on "conventional wisdom" which too often is just hearsay or crowd-sourced rumors and herd mentality.

https://sharena21.springcm.com/Publ...3793b338/31d6eae3-48fd-ea11-b7fc-48df3793b338
https://sharena21.springcm.com/Publ...3793b338/935b410c-1d56-eb11-b800-48df3793b338
https://www.fordservicecontent.com/...nformation/2025_Ranger_P703_TRD_OM_ENG_V1.pdf (p.467 for oil spec)

 

[KayaPayaPigDog]

Cool demonstration, though perhaps a little "unfair" in the real world, since the change interval was 10,000 miles. In my circles, it's accepted that conventionals and blends should have shorter interval changes than full synthetic.

Would love to have seen 3 engines in the test.

10K changes for both synthetic and conventional, as well as a 3rd engine with conventional that was changed more frequently, such that the cost of the oil+filters was exactly the same.

I personally spring for the full synthetic in my rigs, but it would be cool to know which is "cheaper in the long run", or if the conventional could even compete in wear and varnish no matter how often you changed it.

Awesome point and that totally slipped my mind. They went past the manufacturer recommended conventional oil change limit on this I would think, or even if their recommendation is 10k, growing up conventional oil was changed every 3,000 to stay safe. Thanks for pointing that out!

 

[Just sum guy]

Although the conventional wisdom is 3000 between changes for conventional oil, both products were subjected to the same conditions. I don't know if anyone really knows the recommended intervals for conventional oil, as it seems all manufacturers specify at least a synthetic blend if not full synthetic. Not sure why someone would choose not to use synthetic!

 

[stemplar]

Although the conventional wisdom is 3000 between changes for conventional oil, both products were subjected to the same conditions. I don't know if anyone really knows the recommended intervals for conventional oil, as it seems all manufacturers specify at least a synthetic blend if not full synthetic. Not sure why someone would choose not to use synthetic!

Does Ford actually ever specifically recommend synthetic? They recommend Motorcraft brand, of course, but I didn't see synthetic mentioned in the manual but I might have missed it. Actually, I just searched the pdf version of the manual for "synthetic" and the word is mentioned 5 times: 4 times in regard to hypoid gear oil, and once for something about speech using a "synthetically generated voice" or something. So no recommendation for synthetic oil or synthetic blend that I've seen yet.

 

[KayaPayaPigDog]

Does Ford actually ever specifically recommend synthetic? They recommend Motorcraft brand, of course, but I didn't see synthetic mentioned in the manual but I might have missed it. Actually, I just searched the pdf version of the manual for "synthetic" and the word is mentioned 5 times: 4 times in regard to hypoid gear oil, and once for something about speech using a "synthetically generated voice" or something. So no recommendation for synthetic oil or synthetic blend that I've seen yet.

The digital manual is absolute garbage with regards to searching. These are the recommended oils and if you search the number it recommends synthetic blend SP or full synthetic FS. Kind of crazy that they don’t actually say synthetic but they saved a few bucks by not providing a real manual… I’m still bitter about this hahaha

 

[theGnat]

Does Ford actually ever specifically recommend synthetic? They recommend Motorcraft brand, of course, but I didn't see synthetic mentioned in the manual but I might have missed it. Actually, I just searched the pdf version of the manual for "synthetic" and the word is mentioned 5 times: 4 times in regard to hypoid gear oil, and once for something about speech using a "synthetically generated voice" or something. So no recommendation for synthetic oil or synthetic blend that I've seen yet.

Attaching a screenshot from the 2024 Ford Ranger Owner's Manual regarding engine

oil...

XO-5W30-Q1SP is Motorcraft Synthetic Blend, and XO-5W30-Q1FS is the Motorcraft Full Synthetic.

 

[stemplar]

Attaching a screenshot from the 2024 Ford Ranger Owner's Manual regarding engine

oil...

XO-5W30-Q1SP is Motorcraft Synthetic Blend, and XO-5W30-Q1FS is the Motorcraft Full Synthetic.

Right, but they’re recommending specific Motorcraft products, and NOT recommending synthetic or synthetic blends specifically; there’s a difference.

 

[stemplar]

The digital manual is absolute garbage with regards to searching. These are the recommended oils and if you search the number it recommends synthetic blend SP or full synthetic FS. Kind of crazy that they don’t actually say synthetic but they saved a few bucks by not providing a real manual… I’m still bitter about this hahaha

I provided a link to the PDF version of the manual above, which is easily searchable.

Ford, of course, recommends their Motorcraft oils, and specifically mention the two that meet the API spec for our engines. Those two happen to be synthetic and a synthetic blend; I get it.

But the relevant text with regard to requirements is:
"We recommend Motorcraft motor oil for
your vehicle. If Motorcraft oil is not
available, use motor oils of the
recommended viscosity grade that display
the API Certification Mark for gasoline
engines"

No recommendations or requirements for synthetic, synthetic blend, or conventional so long as the viscosity and API spec are correct.

 

[pablo94sc]

And here I am using Motorcraft syn-blend and 10k intervals like in my Focus. Guess I'll switch to full synthetic, but given the truck is only getting about 12k a year on it, maybe two syn-blend changes a year would be better. Hmmmm

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