Synthetics Gas Mileage

[oravla]

Hi there!
Well, I'm new to this forum, so I will first introduce myself. I'm from Viña del Mar, Chile and right now I'm driving a 99 Chevy S10 and a 97 Opel Omega MV6 (same as the Cadillac Catera).
Congratulations to all in this community, you have a very interesting and entertaining forum

.

Now to the topic of this post. Is there a noticeable performance gain (power or gas mileage) when you compare Synthetic oil vs a Dino oil? (suposing both have the same oil weight). I'm thinking in any kind of oil here: Engine, Transmission, Differential, Power steering, etc...

Thanks in advance

 

[XPR]

I saw a noticeable difference with Amsoil in the oil, transmission and differentials. I'm not sure if you can get Amsoil in Chile however.

 

[Titan]

If they are the same weight...no. If it is an oil that shears significantly...you might see a difference as it gets thinner and thinner. In other words: Synthetics aren't "more slippery". A 12 centistoke viscosity is a 12 centistoke viscosity, no matter what the oil is called: "dino, mineral, blend, synthetic", it doesn't matter.

 

[aquariuscsm]

I`ve tried different synth and dino brands/weights and I`ve never seen any change in gas mileage.

 

[Pablo]

Quote:

---

Is there a noticeable performance gain (power or gas mileage) when you compare Synthetic oil vs a Dino oil? (suposing both have the same oil weight). I'm thinking in any kind of oil here: Engine, Transmission, Differential, Power steering, etc...

---

Where you live, not so much difference, but some....and especially when cold. If everything was at 100°C, sure 12 cSt is 12 cSt. But it's not that simple. Oils must flow when you need the vehicle and in cold places that could be 0°C or much colder or it could be 10°C. And conventional oils are much more viscous at these temperatures.

People will say synthetics don't give your car more power, or better mpg. But they do - especially when you change all the fluids, and especially when cold.

 

[Eddie]

When I changed both differentials, transmission(AT) and engine over to Mobil 1 (same viscosity)in my Subaru Forester I measure fuel mileage for about 1200 miles. I found an increase of 0.4 mpg with a SD of 0.16. The extra cost would never pay back but, I continue with Syn for the extra safety margin?

 

[oravla]

Thank you for the answers.
Now I have a clearer picture. Maybe the good thing about synthetics come up when you see the whole package: longer OCIs, longer components life and a better oil grade (0w30 instead of 10w30, 75w90 instead of 80w90, etc...) gives a slightly better gas mileage.
I used synthetic for the first time this year, when I change the differential oil in the Omega (it is RWD) with Motorcraft 75w90. I didn't know what to expect, but I didn't notice any difference at all. I couldn't compare the gas mileage either, because I had just put some wider tires, wich set back the mileage a little.

 

[glenncof]

All of this discussion is consistent with my own experience/experiments.

The one area where I think so minor gains may be achieved are synth in differentials and power transfer units in cold whether, maybe some improvement with transmissions also (perhaps to lesser extent).

Unlike a engine which comes up to regulated operating temperature some of these other components won't and stay cold so reduction in low temp viscosity can pay dividends.

 

[Dominic]

Mine is also about 1/2mpg better with synthetics. Nothing amazing but its a little. Much better cold cranking though.