I just changed oil this past weekend on my 2004 E60 M54 525i.. I could have sworn I did the right reading and felt comfortable with Mobil 1 5W-30. However, the more I read the more I think I may have made a mistake.

Should I drain the oil and put in another 7 quarts of 0W-30, full synthetic? I'm definitely going to save the 5W-30 if I do -- it was expensive!

The car runs well at 90,000 miles.

Appreciate the input.

 

BMW Long-life rating LL-01 Approved Synthetic Oils for the US Market:

* Castrol Syntec European Formula SAE 0W-30

* Mobil 1 SAE 0W-40

* Pennzoil Platinum European Formula Ultra SAE 5W-30

* Valvoline SynPower SAE 5W-30"

 

i'd leave it. you wont do any real harm.

 

I'd leave it also. Just use Mobil 1 0W-40 if you are using Mobil 1 next time.

 

You will be 100% fine with what you put in there.

 

As long as you are not planning on redlining the engine for an extended period of time, and plan to change your oil in 6 months or 7,500 miles, I would not worry about it.

 

You are quite safe in running 5W-30 in your BMW, indefinitely if you wish.

I'm partial to Mobil 1 as I started using the product 30 years ago, and have used it in every car I have owned since. Bulletproof protection that is cheap and available at any Walmart.

Either M1 5W-30 or 0W-40 will do a good job. Certifying oils to auto manufacturer's requirements is typically very expensive as multiple samples of the oil are run in actual engines and put through a host of lab tests before and after running in the engine. While both the M1 5W-30 and 0W-40 would likely meet the BMW specifications, I believe Mobil chose the 0W-40 for BMW approval because of the slightly better low temperature starting characteristics (the W number) as well as a better HTHS number, which suggests it will hold up a little better under sustained heat and high performance driving without the hydrodynamic oil film that separates key components of the engine from collapsing. The HTHS number is becoming more important today in cars with piston squirters and turbo chargers where the oil is used extensively to cool components in addition to lubricating them.

The downside to using a 40 grade oil is fuel efficiency. Some auto manufacturers are specifying 20 grade oils to meet fuel efficiency standards (the higher the grade the greater the drag on the engine). This is fine if the auto manufacturer specs a 20 grade oil, but this has become a problem (especially in Europe) where a consumer mistakenly grabs a 20 grade oil off the shelf and runs it in an engine where the engine is designed to run the oil hot. The 20 grade oil cannot maintain the hydrodynamic film under the increased heat and severe wear can take place in a short time on key components such as journal bearings.

In general, oils have gotten so good that ANY name brand synthetic oil of the proper grade will do a great job. Even many group III "dino" oils (heavily hydroprocessed mineral base stock) are excellent and will do a great job.

The key with ANY oil, even synthetic, is to change the oil while the additives are still present in reasonable quantities to ensure the oil is still doing its job. While the base stock used is important, the real magic that makes oils so good today are the advanced additives.

Oil ages by the engine hour, not the mile, so if you do a lot of bumper to bumper commuting or short trips (when condensed water in the oil is not boiled off) then I would suggest keeping your oil change intervals closer to 5000 miles. But if you get right on the highway and drive at 60mph when you commute, then your engine hours per mile will be low and you can probably push your oil change intervals to 7500 miles or more and still have plenty of additives available when you change it.

With Mobil 1 available at Walmart for $5 per quart in a 5 quart jug, it is cheap enough that the difference between changing your oil at 5K as opposed to 10K is something like the cost of a cup of coffee per week. I keep it simple and use M1 0W-40 in all three of the family cars (gets hot out here in AZ in the summer) and change them all between 5K and 6K miles.

Some people swear by boutique blender brands (these are oils manufactured by a company who buys base stock produced by one of five or six large synthetic base stock manufacturers, and buys additives made by other chemical companies and then "blends" the base stock and additives in their own secret recipe). Two examples are Amsoil and Royal Purple, both outstanding oils. But if you pay $9-$10 per quart for your oil and then run it longer than 5K miles are you really ahead?

Again, any name brand oil will work if you keep the drain interval reasonable. Feel free to try some different oils.

 

Ah, thanks for the input. I drive around town a bit, but put long miles on the highway a few times a month. I'll probably change out at 5,000 to the 0W-40 for piece of mind.

I went to the Mobil website and downloaded a brochure that talks about what's in the 0W and what's in the 5W and it was interesting .. both say "100% synthetic" and they both say they have the "Super-Syn" technology.

Additionally, the bullets as to the features of each all looked interesting.

Appreciated!