Thicker or lighter oil? 0w-40 or 0w-30

[TheMidnightNarwh]

I have a 2011 335is on a small tune with downpipes. Pushing ~14 PSI on the turbos compared to stock that is 8.

I always had in mind that running thicker oil (0W-40) was better for performance driving since the engines in my car are more sporty than a normal commuter car, but now that winter is coming and it's getting colder I think it's causing really slow warm up time. Oil barely hits operating temp if I'm on the highway or takes a good 15 to 20 minutes to heat up fully.

Next oil change I am unsure if I should put in some 0w-30? From searching it seems 0W-30 would be more normal oil and to put 0W-40 once you start consuming a lot of oil or for higher millage cars, for the 335s

Or will it make barely a difference? I am really unsure and looking for input. Or will switching it up barely do a difference?

 

[slo town]

I would strongly suggest Belgian Castrol 0W-30.

Scott

 

[TheMidnightNarwh]

Originally Posted by SLO_Town
I would strongly suggest Belgian Castrol 0W-30.

Scott


I am currently running BMW LL01 Castrol 0w-40 .

So to be clear, are you saying I should yes switch to 0w-30? If so, I planned on getting some Penzoil Euro Platinum 0w30. I think it's only available oil here in 0w-30.

 

[CT8]

5W-40.

 

[TheMidnightNarwh]

Originally Posted by CT8
5W-40.


Ok guys can we not just list oil grade without explaning me why?

Why would I run a 5w over a 0w when it potentially gets down to -20c here. I'm definitely not putting anything higher than 0w for the winter spec.

 

[jeepman3071]

I would stick with what you are running. Castrol 0w40 meets BMW LL-01 and is a great oil.

 

[javacontour]

I say the same. The most important number in winter is the 0W and if the 0w40 is holding up in the summer, it will hold up in winter as well. You are now taking advantage of the 0w portion of the design.

Originally Posted by jeepman3071
I would stick with what you are running. Castrol 0w40 meets BMW LL-01 and is a great oil.

 

[TheMidnightNarwh]

Originally Posted by javacontour
I say the same. The most important number in winter is the 0W and if the 0w40 is holding up in the summer, it will hold up in winter as well. You are now taking advantage of the 0w portion of the design.

Originally Posted by jeepman3071
I would stick with what you are running. Castrol 0w40 meets BMW LL-01 and is a great oil.



I appreciate the replies! But guys I am clearly mentioning in my original thread that my other oil choice is still a 0w oil, it would be 0w-30. So I will still be taking advantage of the 0w.

But if the castrol 0w-40 is such a great oil I suppose I will keep it. I barely have time to floor it though when I go shopping or things like that because how long is takes to warm up, it sucks.

 

[jeepman3071]

Originally Posted by TheMidnightNarwh
Originally Posted by javacontour
I say the same. The most important number in winter is the 0W and if the 0w40 is holding up in the summer, it will hold up in winter as well. You are now taking advantage of the 0w portion of the design.

Originally Posted by jeepman3071
I would stick with what you are running. Castrol 0w40 meets BMW LL-01 and is a great oil.



I appreciate the replies! But guys I am clearly mentioning in my original thread that my other oil choice is still a 0w oil, it would be 0w-30. So I will still be taking advantage of the 0w.

But if the castrol 0w-40 is such a great oil I suppose I will keep it. I barely have time to floor it though when I go shopping or things like that because how long is takes to warm up, it sucks.



Understood, but I'm not confident a 0w30 would make much of a difference over a 0w40 in that respect.

 

[OVERKILL]

Thicker oil actually heats up quicker, so if the car is warming slower, it has nothing to do with the oil. I'd stick with what you've been using.

 

[TheMidnightNarwh]

Originally Posted by OVERKILL
Thicker oil actually heats up quicker, so if the car is warming slower, it has nothing to do with the oil. I'd stick with what you've been using.


Oh wow really? I did not know that.

 

[JMJNet]

Originally Posted by TheMidnightNarwh


Or will it make barely a difference? I am really unsure and looking for input. Or will switching it up barely do a difference?


I think you have answered your own question.
Stop overthinking. LOL!!!

 

[CR94]

Originally Posted by TheMidnightNarwh
... Why would I run a 5w over a 0w when it potentially gets down to -20c here. ...
That's nowhere near cold enough to be a problem for a 5W-X0.

Another misconception is that your current "thicker oil (0W--40)" is "causing really slow warm up time." It's not.

 

[TheMidnightNarwh]

Originally Posted by JMJNet
Originally Posted by TheMidnightNarwh


Or will it make barely a difference? I am really unsure and looking for input. Or will switching it up barely do a difference?


I think you have answered your own question.
Stop overthinking. LOL!!!


Haha I guess, I just had the misconception that ticket would heat up longer but now that's out of the equation, I guess my only question is 0w-40 protects better than 0w-30 right at operating?


Originally Posted by CR94
Originally Posted by TheMidnightNarwh
... Why would I run a 5w over a 0w when it potentially gets down to -20c here. ...
That's nowhere near cold enough to be a problem for a 5W-X0.

Another misconception is that your current "thicker oil (0W--40)" is "causing really slow warm up time." It's not.


See, that's not what I've been told in the past, even here. If I can go for 0w it will always protect better in colder temps.

 

[Gokhan]

Both German Castrol 0W-30 nor German Castrol 0W-40 are thick oils, as they are ACEA A3/B4, which requires HTHSV >= 3.5 cP.

In fact, 0W-30 has a little thicker base oil than 0W-40, with lower NOACK as a result (8.3% vs. 9.1% for 0W-30 vs. 0W-40, respectively).

The main difference is the viscosity-index improver (VII) content. 0W-40 has 50% more VII than 0W-30. The end result is that HTHSV = 3.5 cP vs. 3.7 cP for 0W-30 vs. 0W-40, respectively. It's a small difference really and may only be relevant if the vehicle is pushed to its limits.

Since 0W-30 has a thicker base oil, lower NOACK, and less VII, it's a better oil than 0W-40 unless the vehicle is pushed to its limits. It's preferred over 0W-40 for 99% of the drivers throughout the year.

The higher KV100 of 0W-40 (12.2 cSt vs.13.5 cSt for 0W-30 vs. 0W-40, respectively) would help lower the oil consumption through valve-stem oil seals if there is any significant amount.

 

[TheMidnightNarwh]

Originally Posted by Gokhan
Both German Castrol 0W-30 nor German Castrol 0W-40 are thick oils, as they are ACEA A3/B4, which requires HTHSV >= 3.5 cP.

In fact, 0W-30 has a little thicker base oil than 0W-40, with lower NOACK as a result (8.3% vs. 9.1% for 0W-30 vs. 0W-40, respectively).

The main difference is the viscosity-index improver (VII) content. 0W-40 has 50% more VII than 0W-30. The end result is that HTHSV = 3.5 cP vs. 3.7 cP for 0W-30 vs. 0W-40, respectively. It's a small difference really and may only be relevant if the vehicle is pushed to its limits.

Since 0W-30 has a thicker base oil, lower NOACK, and less VII, it's a better oil than 0W-40 unless the vehicle is pushed to its limits. It's preferred over 0W-40 for 99% of the drivers throughout the year.

The higher KV100 of 0W-40 (12.2 cSt vs.13.5 cSt for 0W-30 vs. 0W-40, respectively) would help lower the oil consumption through valve-stem oil seals if there is any significant amount.


Wow, everything I thought about oil now makes zero sense. Holy [censored] it's complicated.

I guess I'll just keep running 0W-40. I suppose the wear difference in the end between 0w-30 and 0w-40 is minimal anyway.

 

[BMWTurboDzl]

The cold weather performance will be about the same.

Examples:

M1 0w40: MRV at -40ºC, cP (ASTM D4684) is 21600
Castrol Edge 0w30: MRV at -40ºC, cP (ASTM D4684) is 20400


As you can see both oils are very close.

 

[Triple_Se7en]

If you can locate some Euro 0W30 (Pennzoil/Castrol/Mobil-1), that's the ticket for this winter. Add a little more flow to your oil filter too.
Wix XP
Napa Platinum
K&N Gold

 

[Gokhan]

Originally Posted by TheMidnightNarwh
Originally Posted by Gokhan
Both German Castrol 0W-30 nor German Castrol 0W-40 are thick oils, as they are ACEA A3/B4, which requires HTHSV >= 3.5 cP.

In fact, 0W-30 has a little thicker base oil than 0W-40, with lower NOACK as a result (8.3% vs. 9.1% for 0W-30 vs. 0W-40, respectively).

The main difference is the viscosity-index improver (VII) content. 0W-40 has 50% more VII than 0W-30. The end result is that HTHSV = 3.5 cP vs. 3.7 cP for 0W-30 vs. 0W-40, respectively. It's a small difference really and may only be relevant if the vehicle is pushed to its limits.

Since 0W-30 has a thicker base oil, lower NOACK, and less VII, it's a better oil than 0W-40 unless the vehicle is pushed to its limits. It's preferred over 0W-40 for 99% of the drivers throughout the year.

The higher KV100 of 0W-40 (12.2 cSt vs.13.5 cSt for 0W-30 vs. 0W-40, respectively) would help lower the oil consumption through valve-stem oil seals if there is any significant amount.

Wow, everything I thought about oil now makes zero sense. Holy [censored] it's complicated.

I guess I'll just keep running 0W-40. I suppose the wear difference in the end between 0w-30 and 0w-40 is minimal anyway.

There won't be any bearing- or ring-wear difference at all unless you race the car. In fact, since 0W-30 has a thicker base oil than 0W-40, you will experience less valvetrain and timing-chain wear with 0W-30 than with 0W-40. As I said, 0W-30 is the preferred viscosity for your engine throughout the year, which will increase the performance and fuel economy (slightly lower HTHSV) and keep the engine cleaner (1/3 less VII content). Use 0W-30 if it's available at the same price.

 

[KrisZ]

Thicker oil doesn't not warm up slower. Please stop repeating this myth. If a fluid is more viscous and harder to pump, it means that it will generate more pumping losses and those losses are represented by more heat.

The whole premise behind 0w20, 0w16 oils is to generate less pumping losses, which means less heat, during a cold start and warm up phase and save some fuel. You cannot have it both ways.

And before someone claims that thinner oils take away the heat faster, let me clear up that during a warm up period, the heat from the combustion process is absorbed mainly by the coolant. Oil absorbs very little. The main source of heat for oil are the main bearings, camshafts and the oil pump.

Even once the engine and oil are at operating temperatures, coolant still abosrbs the majority of the heat from the combustion process, that is why we have water jackets and not oil jackets around the cylinders and heads.