[ksalih]

Hey guys, time to change the oil again, and the temps are 110F degrees daily here in Phoenix, AZ. I had used Mobile 1's 0w-40 for the last 6 months, but thought maybe 15w-50 would offer the high viscosity during the hot 110F degrees months lovely Arizona has to offer Does anybody use 15w-50 here in the 100+ F degrees cities? I imagine the 15w-50 would not be ideal for the colder months here in Phoenix, but i'd like to see what others use in the hot months. For those who say "i use recommended castrol 5w-30 because BMW says to" or "I use 0w-40 because it's a European Formula and it's LL01 approved" etc, please, I'd like some other thoughts

[NiVeDh]

I'm running Motul 300V Chrono 10W-40 and it seems to handle the heat slightly better than OEM and Mobil1 0W-40. The 15W might be too thick for cold starts, in my opinion.

[ksalih]

Originally Posted by NiVeDh

I'm running Motul 300V Chrono 10W-40 and it seems to handle the heat slightly better than OEM and Mobil1 0W-40. The 15W might be too thick for cold starts, in my opinion.

Off topic but how did you get your dash to display velocity? pretty neat. i think the 15w would be too thick in the winter, but for the summer months i'd imagine otherwise. Where did you purchase your Motul 300V? I don't see it at the local shops, perhaps online only?

Still, anybody using the 15w-50 in the summer months? I'm wanting to try it before winter hits.

[BMWsky]

Originally Posted by ksalih

Off topic but how did you get your dash to display velocity? pretty neat. i think the 15w would be too thick in the winter, but for the summer months i'd imagine otherwise. Where did you purchase your Motul 300V? I don't see it at the local shops, perhaps online only?

Still, anybody using the 15w-50 in the summer months? I'm wanting to try it before winter hits.

OT- you can have your car coded to do that and it will display the CORRECT speed unlike the car's speedometer.

I would stick with 0w-40 in the summer or the Motul 300v. You can search for the Motul and pick it up off Amazon if you can't find it at one of your local indy shops.

[NiVeDh]

Originally Posted by ksalih

Off topic but how did you get your dash to display velocity? pretty neat. i think the 15w would be too thick in the winter, but for the summer months i'd imagine otherwise. Where did you purchase your Motul 300V? I don't see it at the local shops, perhaps online only?

Still, anybody using the 15w-50 in the summer months? I'm wanting to try it before winter hits.

It can be enabled through coding.

I got the Motul at a local motorcycle racing shop.

[ksalih]

I'll have to search the forums on how to code it. Never knew! Anyways, I might stick with the 0w-40 unless somebody chimes in who has used 15w-50.. anyways thanks for the input!

[BrianMN]

lower viscosity oil does a better job cooling. The only reason you'd want to use heavier oil (or change oil weight in either direction) is to fix some negative characteristic.

What specifically do you think you'll gain by going to a heavier weight?

[ksalih]

Originally Posted by BrianMN

lower viscosity oil does a better job cooling. The only reason you'd want to use heavier oil (or change oil weight in either direction) is to fix some negative characteristic.

What specifically do you think you'll gain by going to a heavier weight?

The hotter summer months require a higher viscosity of oil, because the hot temps will cause the oil to become thinner, therefore not being able to properly protect the internals during the hot operating temps without having a heavier weight (higher viscosity).

[BrianMN]

Originally Posted by BrianMN

lower viscosity oil does a better job cooling. The only reason you'd want to use heavier oil (or change oil weight in either direction) is to fix some negative characteristic.

What specifically do you think you'll gain by going to a heavier weight?

Originally Posted by ksalih

The hotter summer months require a higher viscosity of oil, because the hot temps will cause the oil to become thinner, therefore not being able to properly protect the internals during the hot operating temps without having a heavier weight (higher viscosity).

So what is telling you that you NEED heavier oil? Do your UOAs tell you that the general synthetic 0w-40 oil is sheering or not able to hold it's film?

The thought of needing to change viscosities based on seasons/temps is a pretty old-school mentality dating back to the days of single weight dino oil. Nowadays, with the multi-grade viscosities and general advancements in synthetics, you should be perfectly fine with a 40 hot weight for the hot months and track time.

The downsides to thicker oil is less cooling. I'm not privy to the N54 tolerances since I've never rebuilt one, but there's a chance of running too heavy of oil for tight tolerances..granted- 50w isn't a extremely heavy.

So bottom line: if fully synthetic 0w-40 isn't sheering, then 15w-50 isn't 'protecting' any better. Please don't take this as argumentative, this is a great discussion topic.

[anerbe]

^ +1

Thinner weight reduces internal friction and flows better, thus rejects more heat. Go for a higher weight oil if:

1. The engine is engineered for it - looser tolerances to account for the thicker oil, or

2. Your use is past the point of 40 weight oil effectiveness. i.e. oil is shearing/breaking down where lubrication (not heat) properties are compromised.

Note that heavier weight oil will reduce the flow characteristics of your oil pump (and more drag across all engine passages and oil cooler).

Therefore, unless you have specific reason to run the thicker weight oil (with proof of oil degradation), i would stick with the OEM spec.

[AU335i]

Originally Posted by BrianMN

So what is telling you that you NEED heavier oil? Do your UOAs tell you that the general synthetic 0w-40 oil is sheering or not able to hold it's film?

The thought of needing to change viscosities based on seasons/temps is a pretty old-school mentality dating back to the days of single weight dino oil. Nowadays, with the multi-grade viscosities and general advancements in synthetics, you should be perfectly fine with a 40 hot weight for the hot months and track time.

The downsides to thicker oil is less cooling. I'm not privy to the N54 tolerances since I've never rebuilt one, but there's a chance of running too heavy of oil for tight tolerances..granted- 50w isn't a extremely heavy.

So bottom line: if fully synthetic 0w-40 isn't sheering, then 15w-50 isn't 'protecting' any better. Please don't take this as argumentative, this is a great discussion topic.

Originally Posted by anerbe

^ +1

Thinner weight reduces internal friction and flows better, thus rejects more heat. Go for a higher weight oil if:

1. The engine is engineered for it - looser tolerances to account for the thicker oil, or

2. Your use is past the point of 40 weight oil effectiveness. i.e. oil is shearing/breaking down where lubrication (not heat) properties are compromised.

Note that heavier weight oil will reduce the flow characteristics of your oil pump (and more drag across all engine passages and oil cooler).

Therefore, unless you have specific reason to run the thicker weight oil (with proof of oil degradation), i would stick with the OEM spec.

So if running heavier oil isn't as beneficial as some believe, why do alot of people still run 0w-40 over the OEM spec 5w-30?

[BrianMN]

Originally Posted by AU335i

So if running heavier oil isn't as beneficial as some believe, why do alot of people still run 0w-40 over the OEM spec 5w-30?

Because they need 0w weight for the winter, and it needs 40 weight for the summer?

[AU335i]

Originally Posted by BrianMN

Because they need 0w weight for the winter, and it needs 40 weight for the summer?

thought the motor was built to run specifically 5w-30? does the manual say to run 40 in the summer?

[ksalih]

Originally Posted by AU335i

thought the motor was built to run specifically 5w-30? does the manual say to run 40 in the summer?

it doesn't...(maybe that's the point you're making) but then again most ppl don't experience 115 degree weather 4 months out of the year. for the general public I'd imagine 5w-30 would do just fine, however a higher viscosity oil still makes sense for the few that experience these temps this time of the year :shrug:

[BrianMN]

Originally Posted by AU335i

thought the motor was built to run specifically 5w-30? does the manual say to run 40 in the summer?

I guess it might be a loose guideline... BMW claims you can use 5w30 or 0w40 (Mobil1 specifically)

http://www.bmwusa.com/standard/conte...ngineoils.aspx

[AU335i]

Originally Posted by BrianMN

I guess it might be a loose guideline... BMW claims you can use 5w30 or 0w40 (Mobil1 specifically)

http://www.bmwusa.com/standard/conte...ngineoils.aspx

awesome! thanks for the explanation sir!

[JamesM3M5]

BMW approved LL01 oils are generally 40-weight. The main reason people use 40 over 30 is mainly availability of the LL01/ACEA A3 approved oils. Mobil 1 5W30 is NOT ACEA A3 nor BMW LL01 approved. Mobil 1 0W40 is LL01/ACEA A3 approved, as is Motul 5W40 X-cess. And BMW-branded oil is crap compared to real synthetics. Stay away from Group III synthetic, which is really just conventional oil refined one extra step. Group IV synthetics are PAO based, which is made by breaking apart conventional oil molecules and building up man-made oil molecules from those pieces. Group V synthetics typically do not use any conventional oil base - their molecules are made from decomposed plant materials all by humans.

Running a thicker oil in hot climates would only be necessary if you're really getting the oil very hot. But if your oil temps are consistent (sub 260F per the gauge in the cluster) then you're fine with either 30 or 40 weight oils.

[MDORPHN]

Originally Posted by JamesM3M5

BMW approved LL01 oils are generally 40-weight. The main reason people use 40 over 30 is mainly availability of the LL01/ACEA A3 approved oils. Mobil 1 5W30 is NOT ACEA A3 nor BMW LL01 approved. Mobil 1 0W40 is LL01/ACEA A3 approved, as is Motul 5W40 X-cess. And BMW-branded oil is crap compared to real synthetics. Stay away from Group III synthetic, which is really just conventional oil refined one extra step. Group IV synthetics are PAO based, which is made by breaking apart conventional oil molecules and building up man-made oil molecules from those pieces. Group V synthetics typically do not use any conventional oil base - their molecules are made from decomposed plant materials all by humans.

Running a thicker oil in hot climates would only be necessary if you're really getting the oil very hot. But if your oil temps are consistent (sub 260F per the gauge in the cluster) then you're fine with either 30 or 40 weight oils.

James -

And for those of us who see considerably higher temps (~280-285 on track), what is your recommendation?

Neil

[JamesM3M5]

Motul 300V 10W40 for track use, especially with a tune. Takes heat without breakdown, since it's a full Group V ester-based oil. But at those temps, you NEED a bigger oil cooler.

[BrianMN]

Originally Posted by JamesM3M5

Motul 300V 10W40 for track use, especially with a tune. Takes heat without breakdown, since it's a full Group V ester-based oil. But at those temps, you NEED a bigger oil cooler.

As long as you have new oil before and shortly after each track event, Mobil1 is up to the task of high heat.

http://www.e90post.com/forums/showthread.php?t=630548

Even though oil looked just fine, nobody wants to let temps get that high. AR Oil cooler did practically nothing, but now that I have 2x Setrab 625 coolers, temps will not get above 250.