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Discussion Starter · #1 ·
Hey everyone! While I got my '09 Brabus on jacks waiting for it's front 17" Monoblock VII's to come in I have some free time to ask a question that I hope a bunch of ya Smarties can help me out with! I live in SWFL and Summer is basically here (just about hitting 90's already) and I wanted to know what would be the better, more protective weight oil for my area ~ the standard 0w-40 or a 5w-30 (or something else)?

I must note that I use my car for M-F daily driving stop & go route work about 30 Miles on a highway @ 70mph and 30 Miles on streets (with some traffic but nothing too bad) ranging in speed from 35-55mph on the way back. I will be doing my own oil changes on it since the price for a shop to do so is outrageous and will be doing them at about a 5k-7.5k frequency... I am leaning more towards 5k if 5w-30 is better for my application (as it is also a bit cheaper and thus doing them more often is better/safer etc and a write off for me either way).

I have been through quite a few threads/posts reading as much as I can but couldn't find anything specifically for a REALLY hot climate area as I live in ~ so any help, information & suggestions are greatly appreciated!
 

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Discussion Starter · #3 ·


From the owners manual. Several grades are good for above 86 degrees (F) - 5W-30 apparently isn't one of them. :)
Ahhh good to know! I stumbled upon this video and some info that states ~

Now we're in a hotter climate zone around here, so that's a 5 -30 weight that you can use on a car if it's extreme weather. If you're in a colder, more average climate, you're going to want to use 0-40 weight.
Which is why I wanted to confirm with the Smarties here @ SCOA before making a misinformed purchase/decision.
 

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Discussion Starter · #5 ·
0W-40 seems to be the best "all temp" oil - good for extreme heat & cold. :)
It's actually quite amazing the properties & capabilities of the oil, but the price for it comes at such a premium that I wonder if it may not be beneficial for me since I prefer to err on the safe side and do a more frequent oil change just in case...
 

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Discussion Starter · #7 · (Edited)
It's your money - the 10K interval is pretty cheap when you average out the cost. :)
I factored that as a large benefit but I have read so many threads/posts of owners switching to a more frequent schedule on the 0w-40 which made me wonder if I could do the same but with a less expensive (yet still quality) product (say even 5w-40, maybe a part synthetic or whatever) then I kinda think I can get the best of both worlds with a fair compromise? No? Or am I just crazy :urp: :nuts:

Found this as well in the Technical Stickies ~

APPROVED ENGINE OIL- MUST MEET SPECIFICATION MB 229.5
Mobil 1 Formula M 5W-40
Mobil 1 0W-40
Labco MB 229.5 5W-30
Total Quartz 229.5 5W-30
Elf Excellium 0W-30
Shell Helix Ultra AB 5W-30
 

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Oil preferences and change intervals are up for grabs here and on any other car forum. Everyone has their own idea of what the "best" approach is. About the only thing agreed upon is the days of the 3K mile oil change are over (using a synthetic oil, of course.) :)

BTW, I'm hard pressed to see how the M-B 229.5 spec applies to a Mitsubishi engine... :confused:
 

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I would stay far away from anything xW30. What the hot climate basically means is that the second number is far more important than the first.

The first number is the viscosity at 104*F, the second is viscosity at 212*F. In that kind of climate, you'll be very near 104*F right when you start up, and you'll spend most of the time closer to 212*F.

According to the chart in post #2, MB doesn't think xW30 will reliably keep bearing surfaces in the engine from touching each other in those temps.

If you do use 5W30, I think you should use a much narrower rev range... use manual mode, and keep an extra 500 RPM away from lugging and 1000 RPM away from redline...
 

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I would stay far away from anything xW30. What the hot climate basically means is that the second number is far more important than the first.

The first number is the viscosity at 104*F, the second is viscosity at 212*F. In that kind of climate, you'll be very near 104*F right when you start up, and you'll spend most of the time closer to 212*F.

According to the chart in post #2, MB doesn't think xW30 will reliably keep bearing surfaces in the engine from touching each other in those temps.

If you do use 5W30, I think you should use a much narrower rev range... use manual mode, and keep an extra 500 RPM away from lugging and 1000 RPM away from redline...
And how do you explain Ford & Honda using 5W20...?
 

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From the owners manual. Several grades are good for above 86 degrees (F) - 5W-30 apparently isn't one of them. :)
It's probably worth noting that the oil charts outside of the US do, in fact, list 0W-30 and 5W-30 as being appropriate for temperatures above 86 degrees.

Evilution has a "rest of world" chart for reference: Evilution - Smart Car Encyclopaedia
 

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Part of the reason I just had the oil changed and was not concerned about using Mobil 1 5W-30, the other being if it's good enough for an LS6 engine it's good enough for the engine in the smart. YMMV, of course. :)
 

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And how do you explain Ford & Honda using 5W20...?
Their engines are designed differently.

Bearing tech [epi-eng.com]

BOC = Viscosity x RPM x Diameter x K / Unit Load

To avoid bearing wear, we're trying to keep BOC above a certain point (about 35 in that apparently unitless explanation). When you go below that BOC, that's lugging. I realize that that's not how lugging is sometimes defined, but I think it's by far the most useful definition.

Take the case of a smart cruising at 35 MPH in 5th, a case that a lot of us seem to think of as lugging. The TCU was programmed to do that, so it's obviously not a problem. The MB engineers thought that those conditions gave a reasonable BOC when using an oil that's OK by the chart in post #2. If you use a lower viscosity, that lowers BOC... possibly below what's acceptable.

To compensate for it, you have to either have bigger bearings (diameter and unit load) or use a higher RPM.

Engines that spec 5W20 have to either use bigger bearings or higher RPMs to be able to do so.
 

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It's probably worth noting that the oil charts outside of the US do, in fact, list 0W-30 and 5W-30 as being appropriate for temperatures above 86 degrees.

Evilution has a "rest of world" chart for reference: Evilution - Smart Car Encyclopaedia
The engines for the rest of the world are also built differently. It could even be something as simple as the gearbox being programmed with a bit higher shift points.

Part of the reason I just had the oil changed and was not concerned about using Mobil 1 5W-30, the other being if it's good enough for an LS6 engine it's good enough for the engine in the smart. YMMV, of course. :)
An LS6 may be built with bigger bearings than a smart, and/or may not be revved the same way.
 

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The engines for the rest of the world are also built differently. It could even be something as simple as the gearbox being programmed with a bit higher shift points.

An LS6 may be built with bigger bearings than a smart, and/or may not be revved the same way.
>They are? How so? Specific differences, please.

>It's a 350 ci V8 so the bearings are certainly larger; same 6.5K redline as the smart, with six times the horsepower and accompanying loads. I think the smart will handle Mobil 1 5W-30 just fine. :)
 

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The engines for the rest of the world are also built differently. It could even be something as simple as the gearbox being programmed with a bit higher shift points.
Do you have any actual proof of this? I'd be extremely surprised if Mitsubishi were supplying special "US-spec" engines to smart, and even more surprised if Mercedes-Benz used something such as minor shift point variations (which we also have no proof of) as a basis for the oil chart in the US manual.

The more likely scenario is that the chart was intended to more positively portray 0W-40 as opposed to the more commonly-available 0W-30 or 5W-30 for use in all US climates (of which Mobil 1's 0W-40 is the most readily available "MB-approved" variant here in the US).
 

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>They are? How so? Specific differences, please.

>It's a 350 ci V8 so the bearings are certainly larger; same 6.5K redline as the smart, with six times the horsepower and accompanying loads. I think the smart will handle Mobil 1 5W-30 just fine. :)
At least older US-spec smarts were 10:1 compression ratio, while the N/A smarts for the rest of the world were 11.4:1. It remains unclear what compression ratio new US-spec smarts are, but the old ones definitely weren't ROW-spec.

The LS6 has bigger bearings, but it also is designed to operate at lower RPM, has a bigger bore and I assume a longer stroke (leading to higher loads)... there are too many variables for us to say how things work for them as compared to a smart.

Do you have any actual proof of this? I'd be extremely surprised if Mitsubishi were supplying special "US-spec" engines to smart, and even more surprised if Mercedes-Benz used something such as minor shift point variations (which we also have no proof of) as a basis for the oil chart in the US manual.

The more likely scenario is that the chart was intended to more positively portray 0W-40 as opposed to the more commonly-available 0W-30 or 5W-30 for use in all US climates (of which Mobil 1's 0W-40 is the most readily available "MB-approved" variant here in the US).
See above. New smarts may have been standardized to ROW-spec, but the full oil viscosity chart was released before that happened even if it did.
 

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Discussion Starter · #20 · (Edited)
It's probably worth noting that the oil charts outside of the US do, in fact, list 0W-30 and 5W-30 as being appropriate for temperatures above 86 degrees.

Evilution has a "rest of world" chart for reference: Evilution - Smart Car Encyclopaedia
Now I am getting even more confused (between jwights chart & evilutions chart) LoL! Because if I can use a 5w-30 or even a 10w-40 then I can get those for a much lower price then do the change @ every 5,000 and be fine with that...BUT now what about semi-synthetics? I ask this simply for the reason that my local shop does a semi-synthetic 5w-30 oil change for $9.99! Now, I am not trying to be "cheap" (as I don't mind paying for confidence,safety and security) but since I will be doing a minimum of 500+ miles a week my oil change schedule will be a lot more often than most and being frugal/economical in these times is not the same as being "cheap".
 
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