Oil Viscosity and density Question

[shangapol]

Hello Folks,

I need help with this, I do the Maintenance of my Yaris Sedan 07. I forgot the SAE of the oil that I put on the last Oil Change. So, If the SAE is 20w/50, Can I change to 15w/40? I know I can change 15w/40 to 20w/50 but can I put again 15w/40?. My Yaris and I are from Venezuela so is common to use this type of Oil. Now, my Yaris has 50k Mile (80000kms).

Pleeeese Help me:help: with this, Yaris-Fans... Thanks!!:w00t:

Merry X-Mas!!

[CTScott]

Which engine does your Yaris have? Running 20W/50 sounds like you might have the 1.4L diesel.

[shangapol]

Hello Dude,

My engine is 1.5L L4 Gas DOHC Distributorless Naturally Aspirated SFI Electronic FI MFI (02/2007 TOYOTA YARIS (NCP93L-BEMRK) GEN LHD 1NZFE MTM). Here in Venezuela we have a lot of traffic, hills and the weather is always warm to hot.

Thanks for help pal... Merry X-MAS!!

[shangapol]

Also Caracas (Capital City of my country) lies between 760 and 910 m (2,490 and 2,990 ft) above sea level. I think this is important to know why we used to use that types of oil.

Thanks Again...

[shangapol]

Sorry again, the oil is Semi-Synth for both.

[IllusionX]

I don't think you should use high viscosity oil, even at high altitude. You only need more frequent oil change under these extreme conditions.

But then, Denver is at a higher altitude point than your city.. at 5,280 feet

[CTScott]

I would agree that that high of viscosity oil is not necessary. The highest I would go would be 10W/40. With 20W, all you are going to do is make the engine work harder and burn more fuel.

[shangapol]

I understand, but, If my motor have 20w/50 Semi-Synth, Can I change to 15w/40 Semi-Synth?

Thanks CTScott.

[CTScott]

I understand, but, If my motor have 20w/50 Semi-Synth, Can I change to 15w/40 Semi-Synth?

Thanks CTScott.

Yes. You can change to a different viscosity without a problem. If 10W/30 or 10W/40 is available I would purchase that instead.

[frog13]

Use what your manual advises.....no issues then.

[JimKellyfan]

I think they all use 5w30, do they not ?
The numbers can be thought of in how they pour at what temp, really.
Picture cheap vegetable oil and its thinness, then filipio barrio olive oil and its thickness.
5w30, is a 5 weight oil (or thinner) at 0 degrees centigrade and a 30 weight oil (thicker) at 100 degrees centigrade.
And so on.
So, picture cold start up, one would want a thinner oil then, to minimize damage until the oil defies gravity with the pump.
Toyota went to 0w20 eventually, except where they had more performance or heavier duty applications and stuck with 5w30 on those.
My opinion, I think Toyota is paying less disposal fees on the sale of each car now that they recommend an oil change every 10k miles with 0w20.
But, another benefit of the lighter oil is fuel mileage.
0w20 and its benefit on fuel mileage is there, but, my opinion, not worth it.
I would go with 5w30, or if you are abusing it, maybe 5w40 and full synthetic.
I will never go more than 5k on my oil change, and keep an eye on what it looks like on the stick and change early if it appears to be breaking down and/or dissipating.
Make sure to, to stay the same or higher rating as well (SM, SN, SL and so on)
That is a quality (how many chunks of crud) grading.