0W-30 or 5W-30 ?

[felixcat]

My car's user manual (Lexus IS) states that the best choice is 5w30.

How ever I heard some people say that 0w30 can also be a choice. Plus here in town I can get the GC 0W-30.

For 5w30 I can go to the new Castrol Edge. I am planning to do the OCI according to the factory manual, which is 5k miles.

So my question is: from the aspects of performance and engine protection, is 0w30 absolutely better than the 5w30 grade? Since the engine is designed for running 5w30, what's the potential problem if using 0W-30?

 

[Steve S]

Does the mfg recommend a syn oil? 5,000 oil change intervals is silly when syn oil is being used. 0w and 5w30 are really the same for what your intended use is.

 

[mechtech2]

Zero potential problems.
When cold and at intermediate temps, the flow will can be a bit better with the 0-30. And that is a good thing.

 

[felixcat]

The manufacture does not mention the synthetic thing.

OK, not considering the oci, just for the performance and engine protection, which one is more preferred? 0w or 5w?

Originally Posted By: Steve S
Does the mfg recommend a syn oil? 5,000 oil change intervals is silly when syn oil is being used.

 

[d00df00d]

This is a complex topic, but the short answer is that when you're dealing with good synthetics, there isn't much of a difference between 0w30 and 5w30, all else equal between the oils.

You live in Texas, so oil flow in sub-freezing temperatures won't be an issue. Any good synthetic 5w30 or 0w30 should flow well enough on a cold start for you.

If your car burns any oil, it might burn the 0w30 slightly faster. Other than that, there is no inherent problem with a 0w-30.

At high temperatures, a 0w30 will usually retain its viscosity a little better than a 5w30, just because it has a higher viscosity index. However, the difference is usually very small and doesn't matter unless you're driving hard.

Honestly, if you're trying to decide between GC and Castrol EDGE 5w30, and both meet your warranty requirements, I would pick whichever is cheaper.

 

[bepperb]

I assume you won't see much benifit with 0w vs 5w because you won't see many cold starts living in TX. So there's really going to be very little difference for you.

That being said, 5000 miles on syn is a little silly. Is it an IS300, then maybe. But the new v6's I would go 7500. No maitenance minder?

 

[felixcat]

Originally Posted By: bepperb
I assume you won't see much benifit with 0w vs 5w because you won't see many cold starts living in TX. So there's really going to be very little difference for you.

That being said, 5000 miles on syn is a little silly. Is it an IS300, then maybe. But the new v6's I would go 7500. No maitenance minder?


I have the new V6, the maintenance reminder showed up at 5k miles. Maybe my car is new and it only have 5k miles on it, factory want owners do the first oil change sooner than normal?

 

[d00df00d]

Usually.

 

[PandaBear]

Originally Posted By: Steve S
Does the mfg recommend a syn oil? 5,000 oil change intervals is silly when syn oil is being used. 0w and 5w30 are really the same for what your intended use is.


IS250 has a direction injection engine and a 6.6 qt sump, and still ask for 5k OCI. What seems to be the reason is that fuel dilution for DI engine is a problem and they don't want you to mess around with extended OCI.

I'm saving the synthetic for the older cars, and use the cheapest dino and 5k OCI here.

 

[d00df00d]

6.6 quarts of synthetic oil every 5,000 miles on a 2.5L NA V6 making 204 hp?

Who are those people, and what have they done with the real Toyota...

 

[felixcat]

Originally Posted By: d00df00d
6.6 quarts of synthetic oil every 5,000 miles on a 2.5L NA V6 making 204 hp?

Who are those people, and what have they done with the real Toyota...

204HP and 185lb-ft torque is actually quite good for a 2.5L NA engine: it means for every liter it produces 81.6HP and 74lb-ft torque.Compared to other competitors with similar NA engine displacement (V6 and
BMW 328 230HP/[email protected] = 76.7HP/L and 66.7lb-ft/L;
MB C300 228HP/[email protected] = 76HP/L and 73.7lb-ft/L;

Dyno test shows while under 3.5k rpm, the energy of this 4GR-FSE engine produces has no big difference between the 3.5L 2GR-FSE. The power gap of 3.5L vs 2.5L happens after the 3.5k rpm line.

 

[d00df00d]

I know. I just think either I'm missing something important or Lexus made a mistake somewhere. Those competitors you listed will run 10k-15k mile OCIs on the factory spec oil or an approved alternative. That's double or triple the OCI on similar quality oil, for only 5 less hp/L and much more total hp...

What oil does Lexus recommend for your IS?

 

[d00df00d]

By the way, I did some more reading. I had initially presumed Lexus specs a synthetic for the IS250 based on a couple of sources, but now I'm seeing that it's probably a conventional or synthetic blend.

If it is a conventional oil, then a 5,000 mile OCI makes sense, my comparison with the Germans was unfair, and I sincerely apologize.

Either way, it's important to know. If you're going to run a conventional, there may be a good argument for a 10w30, depending on your usage. Any way you can find out?