5w40 oil, is this ok?
- Thread starter synthedup
- Start date
I had a mechanic do the same and found I started to get oil consumption, switched back to 5w30 and it was fine.
If you have no issues stick to spec but don't worry about it until the next change.
If you have no issues stick to spec but don't worry about it until the next change.
Historically I know a lot of mechanics work on the basis that as the engine wears, the gaps between bearings and shells get bigger so it is better to use a more viscous oil. That was certainly the case 40 years ago and no harm came from it. But today's engines and BMWs in particular are complex and it is not just a case of oiling the bearings but also getting a good flow of oil through the fine oil ways in the cylinder head and creating the right pressure for the hydraulic valve lifters and variable valve timing to work optimally.
Personally I would stick to BMW recommendations regardless of the mileage. BMW would have endurance tested the engines during the design and development and changed the oil at regular intervals with oil to the original specification. I don't know BMW endurance test specs but I would expect engines to be tested to at least 150k miles. They would not increase the viscosity as the test goes on and if they did they would have this in their maintenance schedule.
Personally I would stick to BMW recommendations regardless of the mileage. BMW would have endurance tested the engines during the design and development and changed the oil at regular intervals with oil to the original specification. I don't know BMW endurance test specs but I would expect engines to be tested to at least 150k miles. They would not increase the viscosity as the test goes on and if they did they would have this in their maintenance schedule.
Magicarcher said:
Agree - the local mechanic doesn't know better than the designers of engines and oil. In fact both the oils you [op] have mentioned are the same viscosity when cool, just at 100c the 40 can thin less than the 30.
While amateur mechanics make it seem logical that thicker oil doesn't pass more worn cylinders and squeezed out of bearing slower, unless you are experinecing oil loss, then the disadvantages probably outwieght he advantages - lower fuel economy, less flow rate to key components, etc.
In future I'd just stick the the handbook spec.
synthedup said:
it's fine (his reasoning may be nonsense but the use of that oil matters not), ignore the scaremongerers
5w30, 5w40, 0w40 etc are all fine, you'll notice no difference and dealers will use one of them as well including bmw dealerships, last time i used one for a free service with my z4 they used 5w40, i've used it since.
but it's had all 3 in it at one point or another.
Ant said:
I'd have to disagree with that.. Try putting those in a S54 engine and see how far that gets you...
Mike
Ant said:
Not necessarily true . All depends on condition of engine & going up to a thicker grade may not do any damage but result in a small drop in mpg .
If it was my car & not consuming oil between services id stick with 5w 30 & be more particular as to which brand you use
Agreedmr wilks said:Ant said:
Not necessarily true . All depends on condition of engine & going up to a thicker grade may not do any damage but result in a small drop in mpg .
If it was my car & not consuming oil between services id stick with 5w 30 & be more particular as to which brand you use
I wouldn’t change it immediately, but wouldn’t deviate from spec in the future
Ant said:
I have been involved in the design and development of vehicles for OEMs since 1986. All I will say is OEMs go to great lengths to work with oil manufacturers to develop the optimum oil for their engines to deliver an acceptable balance of performance, economy and durability. I have first hand experience where vehicle OEMs have had to change their oil spec late in the development of a vehicle because their original design choice was found to cause unacceptable wear during durability testing. I consider BMW developers to be amongst the best in the world and I trust they have done the necessary testing on the oil they recommend for their engines. So with the knowledge I have, the only recommendation I can give is to stick to the manufacturers recommended oil. Particularly if you intend to keep a car for a long time.
Ducklakeview said:
He's not though is he? "
he's putting it into the car he posted for , if we're going start listing what types of oil may not suit other engines we'll be here a while, but seeing as you picked that engine, 5w30 is what they originally said to put into an s54 (like the e46 m3), and now it's 10w60.
Magicarcher said:
5w30 5w40 0w40 is grand for our engine, like i said the main bmw dealers didn't use 5w30 on mine the last time.
@bit in bold see the reply to ducklakeview
I was illustrating that regardless of what the "local expert" thinks, it's not wise to deviate from what the manufacturer has both developed the engine to run on, and tried and tested it to do so.
Mike
Mike
I certainly agree that the guy in the pit at the quick oil change place might not be the best source of information. I notice that the more-or-less local place seems to use 5w20 for everything, no matter what, which knowledge keeps me out of their hands. Anyway, I did the unthinkable and consulted my owner's manual, which only recommends API spec SJ. That's it. No other recommendations other than "see your dealer", which is the recommendation for everything including washing the windshield. Useless. For a multi-volume document in it's own fake leather folder, it has virtually no useful information.
My copy of the official service manual's section on engine fluids recommends BMW's own 5w30 synthetic, or others as indicated, but makes no mention of LL specs. It also includes a handy chart of recommended grades for various climatic conditions, which chart seems to suggest that for me, where it's always hot, 5w40 is a good choice since it never gets below 70 F for more than a few hours. Again, no LL reference. An internet search gives me a wide range of recommendations, including the very interesting information that Mobil 1 0w40 was LL-01 spec (high sulfur, US fuels. LL-04 is for low sulfur, European fuels) though about 2013 or so, along with a couple of other premium oils such as Castrol Syntec. Curiously, none of these are branded LL-01 in stores at the current time, but I did have an older quart of one on the shelf that was so branded.
The LL specs are pretty obtuse, but from what I can find of the details, they are quite similar to those from VW, Porsche, Audi, and Volvo, differing only in detail. I suspect that the sudden disappearance of LL-01 oil from store shelves has more to do with BMW USA selling their own product than it does with what actually works in the engine.
I also suspect that you non-US people might have an easier time finding LL spec oil than we do.
My copy of the official service manual's section on engine fluids recommends BMW's own 5w30 synthetic, or others as indicated, but makes no mention of LL specs. It also includes a handy chart of recommended grades for various climatic conditions, which chart seems to suggest that for me, where it's always hot, 5w40 is a good choice since it never gets below 70 F for more than a few hours. Again, no LL reference. An internet search gives me a wide range of recommendations, including the very interesting information that Mobil 1 0w40 was LL-01 spec (high sulfur, US fuels. LL-04 is for low sulfur, European fuels) though about 2013 or so, along with a couple of other premium oils such as Castrol Syntec. Curiously, none of these are branded LL-01 in stores at the current time, but I did have an older quart of one on the shelf that was so branded.
The LL specs are pretty obtuse, but from what I can find of the details, they are quite similar to those from VW, Porsche, Audi, and Volvo, differing only in detail. I suspect that the sudden disappearance of LL-01 oil from store shelves has more to do with BMW USA selling their own product than it does with what actually works in the engine.
I also suspect that you non-US people might have an easier time finding LL spec oil than we do.
Kamuela said:
Doesn't the LL spec simply indicate that it will tolerate the car manufacturers ridiculously long intervals between changing ? Which if you care enough about your car to post the above that would suggest you would be following your own regime & change it every year or 7k/8k :wink: then the whole LL capability becomes irrelevant .
I think 5k is a bit early but then it depends on the individual engine and driver.
I aim for about 7/8k or 1 year with 10k being the upper limit before i get uncomfortable. 15k is certainly far too long, horrible muck comes out but then!
Don't forget the gearbox, 30k seems to be a happy interval for me, and to a lesser extent the diff.
I aim for about 7/8k or 1 year with 10k being the upper limit before i get uncomfortable. 15k is certainly far too long, horrible muck comes out but then!
Don't forget the gearbox, 30k seems to be a happy interval for me, and to a lesser extent the diff.
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