Considering Going from 5W-30 to 5W-20...

[GumbyJarvis]

ALSO on top of the whole increased gas mileage, I use a higher flow rate air filter (Spectre) and hotter plugs (Autolite Double Platinum) vs Paper filters or Ford Plugs

 

[GMBoy]

I agree with the overall consensus to NOT go 5w20 but to keep with the 5W30 or, as a few mentioned - OW/30 would be a nice and acceptable alternative. But really, 5w30 is spec'd for the engine and has served you well so keep using that combo. However, with the age and miles I'd actually even consider a 10w30 high mileage oil.

 

[umungus1122]

5w30 and 5w-20 are close enough that I find it hard to believe you'd see any difference. As far as the pump not getting enough pressure, I can't buy it. The 5w-20 will have superior flow, regardless of pressure, which is what is important. As long as you're getting good flow, pressure is irrelevant.

 

[TFB1]

Originally Posted By: umungus1122
As long as you're getting good flow, pressure is irrelevant.

Maybe in your engines but not in mine... If the oil is mostly dumped out of the main and rod bearings, without enough pressure the upper regions of the engine will starve for oil...

 

[bodeh6]

You might want to try Castrol EDGE with Titanium 5w30 which is pretty thin for a 30 weight

 

[umungus1122]

With regard to fluid dynamics, pressure is resistance to flow. If oil flow is within or above the design parameter, the oil is reaching every nook and cranny necessary. During design, a pressure measurement is taken at the appropriate flow rate for proper lubrication, and is used as a measurement to gauge flow, which is handed down into the set of specs for the particular engine. As it were , pressure is used as the measurement for flow. If the flow is superior to design parameters at a lower pressure due to a factor such as a lower viscosity liquid, so much the better.

 

[odie]

Just put SHELL full synthetic 5w-20 ( SN/GF-5 ) in the '08 Yaris . Was using 5w30s up until this time . The previous fill was SHELL synthetic 5w30 ( SN/GF-5 ) and made the engine a bit quieter . Went for a drive after the fill of 5w-20 syn and we noticed the engine to be slightly noisier than the 5w30 syn . Sounds similar when using the PENNZOIL conventional 5w30 ( SN/GF-5 ) before the the SHELL 5w30 synthetic .