Safe to run 5w-30 oil?

[Ocala FR-S]

[quote=ayau;721205]

Originally Posted by Xdragonxb0i

You should be using thinner oil if your car engine isn't reaching normal operating temperature. As oil heats up, it becomes thinner. When it's cold, it's thicker. This means there won't be enough lubrication for the engine.

Said it before I could. I do lots of short commutes and am glad 0 weight oil is doing its job as soon as possible. Agreed, heavier oil for short commuted is a mistake.

[ayau]

Originally Posted by Tt3Sheppard

0w20 for winter 5w30 for summer

No. Stick with 0w-20 unless you heavily track your car.

[driftartist]

its almost as if the engineers knew what they were talking about...

[zc06_kisstherain]

ok. ow-20 is!!

[Hanakuso]

Could you mix them together? Say 1-5 bottles of 0W20 1-5 bottles of 5W30. So a total of 6 or whatever the recommended amount is.

[GNS]

Originally Posted by Hanakuso

Could you mix them together? Say 1-5 bottles of 0W20 1-5 bottles of 5W30. So a total of 6 or whatever the recommended amount is.

Aren't there any 0W-30 synth oils out there? Then you get the 0 weight for cold start ups, and 30 weight at operating temps.

[ayau]

Originally Posted by Hanakuso

Could you mix them together? Say 1-5 bottles of 0W20 1-5 bottles of 5W30. So a total of 6 or whatever the recommended amount is.

Not sure what your goal would be to mix the different oils. I believe the owners manual recommends you to use the same oil unless you can't find the same weight oil.

[ayau]

Originally Posted by GNS

Aren't there any 0W-30 synth oils out there? Then you get the 0 weight for cold start ups, and 30 weight at operating temps.

Someone needs to verify this but...

I believe 0w-20 and 0w-30 will still have different room temperature viscositities. 0w-20 should be thinner at room temperature, therefore, will be "better" for your engine at startup.

Bobistheoilguy.com stresses that no matter what oil you put into your engine, it's still too thick at room temperature.

I think it's safe to assume that Subaru has the most knowledge about their own engine. If they recommend 0w-20, then you should stick to that under normal driving conditions. The only exception would be if your oil temperature runs very hot due to tracking the car (very low population), then you may want to consider 5w-30 to reduce shearing.

[Hanakuso]

Originally Posted by ayau

Not sure what your goal would be to mix the different oils. I believe the owners manual recommends you to use the same oil unless you can't find the same weight oil.

Just thought it would be a balance/compromise between the two oil weights.

[BMWDavid]

Originally Posted by Ryan86

Toyota South Africa have specified fully synthetic Diesel engine oil, 5w30 for our climate.

Is that in the owners manual? I wonder what is called for in the Arab states?

[Porsche]

Originally Posted by Ryan86

Toyota South Africa have specified fully synthetic Diesel engine oil, 5w30 for our climate.

Temperatures are comparable to much of North America, ranging from 70-90 deg F typically during the warmer months of the year.

The difference in oil spec is, I suspect, due to less government interference, and fewer eco-maniacs, and Tree Huggers. This permits the engineers to specify the more suitable oil weight, not needing to live up to any fuel economy constraints. They’re more free to spec the oil that protects the engine BEST.

[bluesubie]

Originally Posted by ayau

The only exception would be if your oil temperature runs very hot due to tracking the car (very low population), then you may want to consider 5w-30 to reduce shearing.

In severe conditions, most 5W-30's (low High Temp High Shear/Resource Conserving) will actually shear more than a 5W-20 because the 5W-30 will have more viscosity modifiers. You can find 5W-30 uoa's where the viscosity has sheared to a lower viscosity than some 5W-20's.

A 5W-20 can also have less evaporation loss than most 5W-30's (measured by NOACK volatility).

-Dennis

[smbrm]

Originally Posted by bluesubie

In severe conditions, most 5W-30's (low High Temp High Shear/Resource Conserving) will actually shear more than a 5W-20 because the 5W-30 will have more viscosity modifiers. You can find 5W-30 uoa's where the viscosity has sheared to a lower viscosity than some 5W-20's.

A 5W-20 can also have less evaporation loss than most 5W-30's (measured by NOACK volatility).

-Dennis

Dennis makes valid points(generally speaking). However you also need to be aware that not all viscosity modifiers have the same shear characteristics. In the arsenal of components formulators do have options regarding the types of viscosity modifiers from which they can potentially select depending on product design performance criteria. However the important part is the overall performance the product delivers not whether component A or B is used.

[bluesubie]

Originally Posted by smbrm

Dennis makes valid points(generally speaking). However you also need to be aware that not all viscosity modifiers have the same shear characteristics. In the arsenal of components formulators do have options regarding the types of viscosity modifiers from which they can potentially select depending on product design performance criteria. However the important part is the overall performance the product delivers not whether component A or B is used.

Good point about different shear characteristics. There have been a few uoa's in WRX's over the past year where Resource Conserving oil held up fine for 7k+ mile intervals (maybe improvements due to the GF5 spec). Of course, there's also the possibility of thinning down and thickening back up again.

A nominate you to do a uoa every 1,000 miles, for a range of different muti-viscosity oils, to see if the viscosity changes. .

-Dennis