Hi everybody,
I am a just few miles due for oil change on my '06 MCS (39k). I used Mobil 1 5w-30 last time, but I noticed a new spec the other day (0w-30) and also 0w-40.
I live in central Florida and enjoy driving my MCS almost everyday!
Can anyone please explain the differences between these three specs?
Which one would you recommend?

Thanks!

Joseph

 

Basically, the first number represents how thick the oil is when it's cold, and the second number represents how thick is it when it's hot. Specifically, a 5W-30 oil has the same viscosity when cold as a straight 5W oil, and the same viscosity when hot as a straight 30W oil.

So both a 0W-30 and 5W-30 will behave the same once your engine's up to operating temperature. The 0W-XX oils are usually appropriate for colder climates where a thicker oil might have problems until the engine's warmed up.

From the 2006 owner's manual, MINI recommends either 5W-30 or 5W-40. I'd go with the 5W-30 unless it's really hot out and you're worried about the heat causing the 5W-30 to get too thin when the engine's hot.

 

It's generally best to use the most narrow viscosity range that your climate requires. Just like everything in life, when you try to make one thing do everything, the less effective it is at doing any one thing. In Florida, there is no reason to use a 0W-XX at all. That is for seriously cold climates where you routinely see temperatures near or below 0F. Some manufacturers (like Honda) are spec'ing 0W-XXs to improve fuel economy at the expense of engine protection. The thinner oil reduces internal resistance which minutely improves mileage, but it also reduces protection. Maybe in winter in Florida you could go with a 5W-30, but I would think most of the time you would want a 10W-30 or even a 10W-40. If you go with Mobil 1, be sure to use the Extended Performance formulas unless you plan to change your oil much more frequently. The regular Mobil 1 is much lower quality than it was several years ago. I strongly recommend Redline oil, but that's a different topic.

Cheers,
-Chris

 

I suggest going to M1's website and looking at the flow rates. 0W isn't the same across the board.

I use 0w-40 M1 in the Mini and GTO.

 

Good point - in the days of conventional motor oil, you had to add a LOT of viscosity modifiers to get a wide spread on a multi-weight oil. That's why the biggest spread you typically saw with conventional motor oil was 10W-40 or 20W-50. The problem with the modifiers was that they didn't contribute to lubrication, and they could break down fairly quickly over the life of the oil, so the viscosity would shift drastically as the oil aged.

It's not as much of an issue with modern synthetic oils, because the oil molecules themselves can be engineered to provide a wide viscosity range without needing nearly as many modifiers. That's why you didn't start seeing oils like 10W-60 or 0W-50 until synthetics came onto the scene. You can even get 0W-60, but it's a special-purpose, hugely expensive oil.

 

So what would be the purpose of a 10w-30 or 10w-40 over the OEM 5w-30?
which one is the best protection for high performance?

Thanks!

 

I love these threads

 

I use the 0-40 here cause we can get 40 and 50 degree shift in temps for one day. Lows in the 20's right now and then up to close to 70 later today. Summer daytime temps in the 90's and winter daytime temps in the 30's.

 

So flow rates for M1

05w-30 104F=64.8 212F=11.3
10w-30 104F=62.0 212F=10.0
00w-40 104F=78.3 212F=14.0

 

There's really no advantage unless the ambient temperatures in your area are so darn hot that a 5W-XX oil would be too thin when you first start up the engine. In that case, a 10W-XX oil might be more suitable.

In the old days of conventional oil, 10W-XX and 20W-XX oils were kind of a necessary evil, because you could only get a spread of 30 between the hot and cold ratings. (In other words, if you wanted the oil to act like a 50-weight oil when hot, you couldn't go lower than 20W when cold, hence the popularity of 20W-50 conventional oil in higher-performance engines.)

Likewise, if you wanted a conventional oil to behave like a 40-weight when hot, the cold rating had to be at least 10W to keep the spread at 30 or below.

With modern synthetic oils, the viscosity spread can be 40, 50 or even 60, so it's easy to make a 5W-50 or 0W-50 oil that flows really well when it's cold, but also protects well after it gets hot.

 

So now I'm confused too, I have an 05' MCS which I've changed its oil ever 5k miles since new with 5w-30 (Factory Recommended) but Mobil 1 Full Synthetic.

I'm about to go buy some more for my 60k mi. oil change and decided to actually check the Mobil 1 website for availability (Ike Shortage) and noticed their recommendation for an 05' MCS is 0w-40: http://www.mobiloil.com/usa-english/....aspx?option=2

Now I'm not sure what to go with... But I don't feel comfortable going with 10w-40 thats recommended by some here because that isn't recommended by either MINI or Mobil 1......

 

Book says 5W-30, go with 5W-30. Unless you're in an area with extreme temp fluctuations, or you drive like Schumacher on your way to work, it's not going to make the least bit of difference one way or the other.

 

Thanx, now the problem is actually finding any Mobil 1 5w-30 ANYWHERE!!!

 

I use Mazola works great!

 

Warning, stupid question: Why does it say castrol 5w 40 on the intercooler cover? Business agreement?

 

Yup......

 

you should use oil that meets the BMW specs for the engine. ACEA A3/B3 and BMW LL-01. If either of those specs are not on the oil bottle, then they're not long interval oils. Both German Castrol 0W-30 and Mobil 1 0W-40 meet this spec. US made Castrol 5W-30 does not. The BMW supplied 5W-30 (from the dealership) does meet ACEA A3/B3. This oil come from Germany.....

 

Just noticed the spec change on the MINIUSA site.

Interesting to see that they've shied away from the Mobil 1 5w-30 in the same way that VW did for their 1.8t engines after some sludging and turbo coking episodes...

 

M1 has always had shear issues over it's life. With the new engines and their turbo's, MINI might have found some issues with the oil getting too thin and cooking the turbo.

 

Looking at the M1 site,
M1 extended performance 5W30 meets ACEA A5/B5, but
regular M1 5W30 only meets A1/B1
regular M1 0W40 meets A3/B4 and BMW Longlife-01
Advanced fuel economy M1 0W30 only meets A1/B1
Racing M1 0W30 is not recommended for street cars.

Based on that the M1 0W40 meets MINI's requirements,
Ext. Perf M1 5W30 meets some,
and M1 5W30 and AFE 0W30 and Racing 0W30 don't.

BTW, Amsoil 5W40 European Car Formula (which I'm using at the moment)
is recommended for A3/B4 adn BMW LL-04 applications,
although it isn't actually formally certified for them

 

Looks like from the MINIUSA site that Valvoline Synpower 5W-30 will work, and meets the right weight and requirements, I'll give that a shot going forward. I used Mobil 1 5W-30 the last two oil changes, but I also change my oil anywhere from 3000-5000 miles.

 

I just happened to run across a case and a half of Amsoil 5W-30 the other day. I would imagine this would meet the requirement? This oil is several to three years old but been stored in a climate controlled building all the time. But the storage age is all that sort of bothers me about it. However I can get it for free... so it is tempting...

And thoughts?

 

castrol full syn 5w 30w

 

I've been using Mobil 1/ 0w-30. It's been working fine for me, and I am getting better fuel economy (1-2mpg) as they advertise. Anybody else using this one?
I live in Central Florida and have run this oil type of oil for 7k+ miles (2nd oil change already)

 

Which oil is it? They have a couple 5W-30's at the moment.
The XL-5W30 only rec. for A1/B1, and the 100% synthetic 5W30 is rec. for A5/B5, but not BMW LL-01.
Old stock may have different rec's, but these should be listed on the label of the oil container.