0W-20 in a BMW M-60

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Originally Posted By: kschachn
I think the chart does allow 5W-20 for cold weather, but that was most certainly some inferior dino oil available in 1994. I think old charts are pretty much useless these days, irrespective of the fact that a lot of automakers seem to persist publishing them in today's manuals. I've seen some that really don't make sense.

I have some older vehicle charts and I've never seen one didn't make total sense to me.

The following I posted in another thread but it's applicable I think:

"Even for cars built in the 70's and 80's the 20W-20 grade was still spec'd as an option for fall, winter and spring use.
For my first car, a '72 Ford Capri, 20W-20 was spec'd for ambient temp's from 25F to 70F. My '86 Porsche has similar recommendation for the 20W-20 grade from -10C (14F) to 15C (60F).
Interestingly enough the 5W-20/30 grades were specified for my Capri only for sub-freezing temps from 32F down to -40.
Much the same for my Porsche with the 5W-20 grade from -10C (14F) and lower and a dino 5W-30 from -30C (22F) to 32F.
The 20W-20 grade had fallen out favour by that time because the now common 10W-30 grade had much better cold start performance, spec'd down to -25C (13F) although only up to 70F for both of these European cars.

Obviously manufacturers didn't have a lot of confidence in light multi-grade mineral oils of the day.
Porsche spec'd a 0W-30 up to 30C (86F)."
 
Hi,
CATERHAM - I can confirm the early popularity of the 20W-20 viscosity (one was Castrolite). This viscosity was popular in 356 Porsche and VW cars (as HD20) and most BMC A and B Series engines survived on it. The 20W-50 viscosity was especially developed by Duckhams (and later Castrol) for the Mini - totally due to the integrated power unit. The 20W-50 caused oil pump failure in these engines too!

Later, 20W-50 became the "fix it" lubricanst for all and sundry!

10w-30 became popular in Oceania and Europe from the mid 1950s (Mobiloil Super in Gold one pint cans was one)!

It was made increasingly popular in Europe because of the US Personnel involved there in "cold war" activities. Their US cars needed it!!

During the 1960s in Scandinavia and Germany for instance 20W-20 and SAE30 were still front runners and 10W-30 was a backstop. By this time Porsche, MB and some others were busily commencing promoting their Approved Lubricants (Marketplace Name etc). Very comprehensive Handbooks on this subject were produced by the Manufacturers for many years

My philosophy has always to use the lowest permissible viscosity as decreed by the engine's Manufacturer for its application
 
Originally Posted By: CATERHAM
Originally Posted By: edyvw
kschachn said:
I'd put there GC 0W30 or M1 0W40.
It is old fashioned European engine that simply loves heavier oils.

That's an old wife's tell.
Both GC and M1 0W-40 are heavier than necessary for optimum winter use. The M1 0W-30 he is using now actually exceeds the specified viscosity requirements of his engine as it does for my somewhat newer M52 engine.

Yeah, I know. paper says one thing, practice another. Well, sure just go ahed, use that!
Personally, if someone put 0W20 in my BMW with any engine, let's say he would loose a job!
At that time people in Europe used 10W40 in those engines.
But what they know, they just made that engine!
 
Originally Posted By: CATERHAM
Originally Posted By: edyvw
kschachn said:
I'd put there GC 0W30 or M1 0W40.
It is old fashioned European engine that simply loves heavier oils.

That's an old wife's tell.
Both GC and M1 0W-40 are heavier than necessary for optimum winter use. The M1 0W-30 he is using now actually exceeds the specified viscosity requirements of his engine as it does for my somewhat newer M52 engine.


What ARE the "specified viscosity requirements" for the engine, and where does one find this information ?

cst please, as that's viscosity.
 
Here you go. The typical old BMW multi-arrow chart and the loose specs:





Originally Posted By: CATERHAM
kschachn, I'm curious what you're '94 BMW M60 oil recommendation chart and related literature says from your drivers manual.
Can you post it?
 
Thanks for posting that.
I am surprised that you've got the same type of all grades recommendation chart as for my older Porsche. My only two MYs newer Bimmer only recommends two grades (other than the synthetic *Special- Oils) with an SG energy conserving 5W-30 dino up to 50F although the manual says "you can continue to operate the vehicle for short periods of time at temperatures above that..." as does your manual.

It looks like by 1996 BMW had a bit more confidence in the shear stability of the mineral 5W-30 by recommending it for higher max' temp's than for your car.

If you do decide to run a 20 grade oil you can have some fun properly claiming that's what BMW spec's for my car which will no doubt freak out the heavy oil only in BMWs set.
 
Hi,
from the Chart it's easy to see why 20W-50 retained it's popularity in many marketplaces!

The Porsche 928 fraternity loved 20W-50 and here in OZ some "Porsche Specialists" even went higher to "..keep up hot idle OP in the summer.."". I ran 5W-40 Delvac in mine (32V)with great results even at 40C and on many long trips at very high speed. The 928 FF was Shell XMO 5W-40 from around 1990 - the first production cars to have a synthetic FF

A synthetic 5W-50 (or 15W-50) still has a lot to offer IMO in these cases
 
OK, parsing that chart a bit - why would they say 5W-30 is only good up till about 25 degrees Fahrenheit? What was their rationale? Was it excessive consumption or some sort of diminished engine protection?

Also, what were the "special oils"? Synthetic? And without stating what the viscosity of the special oil is/was, how can they specify that it was good from -20 to the upper limit? Are they assuming the BMW dealer would specify more than one possible special oil depending on ambient temperatures? Did BMW ever have more than one special oil?

And why all the emphasis on ambient? I get why this is important for starting, but surely it can't be all that relevant for operation. Is it? This is a question I always have for any oil chart based on OAT.

This is why I find most oil charts to be confusing. And this one in particular.

Is a modern 5W-30 (synthetic or not) just that much better that you don't rip it out at 25 degrees?
 
Wow lots of questions.

The reason a dino 5W-30 was "only" good to 25F was shear instability during long OCIs but remember they say it can still be used for short periods at higher temp's. My interpretation of BMW's qualification is that you can still use a lighter oil beyond the maximum temp' range on the chart but avoid using full power. Not using WOT particularly at lower rev's dramatically lowers the viscosity demands of an engine.

The importance of ambient temp's is that it does correlate with maximum oil temp's.
When the ambient temp's are below freezing it is very difficult to get oil temp's up even into the low normal range of say 80C with many vehicles and definitely Bimmers. Roughly speaking a 20 grade oil has the same operational viscosity at 80C that a 40 grade oil does at 100C.

The advantage of synthetic oils vs the cheaper dino oils of the day is that they are much more shear stable and therefore can maintain the required minimum viscosity at higher temp's.

Having oil pressure and oil temp' gauges is the only way to know what the actual operational viscosity in an engine is a any moment and how much it varies. Operational viscosity, once the coolant is up to temperature, is affected by many factors in addition to ambient temp's and oil shear. There's also fuel dilution and engine load and rev's, road speed and engine running time all will affect oil temperature.

I strongly recommend that all members who want to understand the topic install oil gauges. Quite frankly it is impossible to fully understand the subject of oil viscosity in an engine without the first hand experience gauges provide.
 
I would not recommend using anything less than a 0/5w30 in any BMW, and I honestly don't see any reasonto. The ideal oil weight IME is 0/5w40 for non-M cars.
 
Why?

Originally Posted By: nleksan
I would not recommend using anything less than a 0/5w30 in any BMW, and I honestly don't see any reasonto. The ideal oil weight IME is 0/5w40 for non-M cars.
 
Originally Posted By: CATERHAM
The reason a dino 5W-30 was "only" good to 25F was shear instability during long OCIs but remember they say it can still be used for short periods at higher temp's. My interpretation of BMW's qualification is that you can still use a lighter oil beyond the maximum temp' range on the chart but avoid using full power.

In line with what you're saying, my Audi's manual advised under the chart that there's no reason to panic if ambient temperatures fall outside the chart limits for a period.

@nleksan: Remember that the special approved lubes were in their infancy at the time of the chart.
 
With the extra strain BMW motors put on oil (VANOS, lifters, and so on), running too thick or thin of an oil CAN change the way your car driver by altering the cam timing, etc.

Is it a big risk? No.
Is there any reason to use 0w20? No.
 
VANOS doesn't really put much strain on the camshafts. Valvetronic requires more protection and drove a lot of the requirements of later BMW specifications, but wasn't launched until 2001.
 
It's all about operational viscosity and it's no different for later model cars.
M1 0W-20 has the same viscosity at 86C that the BMW 5W-30 has at 100C. For TGMO 0W-20 it's at 84C.
All cars run lower maximum oil temp's in the cold winter months and for normally aspirated Bimmers it's especially so.
If ambient temp's don't get above freezing you won't be seeing oil temp's much above 80C.
Consequently in running a 0W-20 in the winter, yes you're using a lighter oil grade but you're not running a lighter oil.
 
That's one of the best things you have said.

I agree, it always seems misleading to me that so much discussion goes into oil grade when it is really the viscosity at a determined temperature that matters. There are thick 20 multi-grades and thin 30 multi-grades, right? So to say categorically that a 5W-30 is good and a 0W-20 is bad isn't based on anything really.

Originally Posted By: CATERHAM
It's all about operational viscosity and it's no different for later model cars.
M1 0W-20 has the same viscosity at 86C that the BMW 5W-30 has at 100C. For TGMO 0W-20 it's at 84C.
All cars run lower maximum oil temp's in the cold winter months and for normally aspirated Bimmers it's especially so.
If ambient temp's don't get above freezing you won't be seeing oil temp's much above 80C.
Consequently in running a 0W-20 in the winter, yes you're using a lighter oil grade but you're not running a lighter oil.
 
Well, I previously ended up changing the oil to M1 0W-30 mostly out of ignorance as to what the oil pressure is in that engine. The car is parked outside in northern Wisconsin, and last night the low got down to around -24 degrees F. Tonight it is forecast to be -22 (and -20 the next), and the car started just fine.

It is always amusing that even though M1 0W-40 and 0W-30 are both "0W", the MRV of the AFE is less than half of the 0W-40 at -40.
 
There is a lot more to the viscosity of an oil in an engine than how well it flows down a tube under low shear (gravity).

I'd be far more concerned about the low oil temperatures impact on the antiwear chemisty than kinematic viscosity, also the cold running and low oil temperature will promite fuel dilution which wont be boiled off, the oil will thin out as it ages, I'd not go below a 3.5cP HTHS on a BMW engine, especially if you plan on filling the sump with a load of fuel and water.

a 0W with 3.5cP HTHS is going to be mainly PAO with a very good pour point and MRV, this is what I'd be interested in over the Kv100. Plus the fact it will have a chance of carrying the LL01 specification. A 5W-20 2.6/2.9cP HTHS API SM/SN oil is likely to be all group III, also the TBN wont be as robust as an API on oil
 
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Originally Posted By: kschachn
Well, I previously ended up changing the oil to M1 0W-30 mostly out of ignorance as to what the oil pressure is in that engine. The car is parked outside in northern Wisconsin, and last night the low got down to around -24 degrees F. Tonight it is forecast to be -22 (and -20 the next), and the car started just fine.

It is always amusing that even though M1 0W-40 and 0W-30 are both "0W", the MRV of the AFE is less than half of the 0W-40 at -40.

That really shouldn't come as a surprise. For the same chemistry, the heavier the oil (higher the grade or higher the HTHSV to be more precise) the worse it's extreme cold performance.
The other thing to keep in mind is the parabolic nature of oil at extremely cold temp's. Even for 0W oils the viscosity change with temperature as you approach -40 degrees is dramatic. Just one degree can raise or lower an oil's viscosity as much as 20% while at -20C it could be as little as 1%.
That's why the MRV rating at -40 may have no relevance at temp's as low as -30C in comparing various oils.

That said, M1 0W-30 does have a very low MRV, lower than most 0W-20s, suggesting it's formulated with PAO base stocks.
The latest SN version of M1 0W-40 is GP III based, hence it's much higher MRV. Fortunately we Canadians are still getting the PAO based SM version of M1 0W-40 with a MRV in the 20,000cP range.
 
Well, not a surprise from the physics of oil, but from a marketing standpoint. I think it is easy to think that any oil marketed as a 0W-something is superior for low temperatures but that's not how the grading system works. Clearly from this example this 0W-40 is far thicker at low temperatures than their 0W-30 product. And a lot more than their 5W-30 as well.

Originally Posted By: CATERHAM
That really shouldn't come as a surprise. For the same chemistry, the heavier the oil (higher the grade or higher the HTHSV to be more precise) the worse it's extreme cold performance.
The other thing to keep in mind is the parabolic nature of oil at extremely cold temp's. Even for 0W oils the viscosity change with temperature as you approach -40 degrees is dramatic. Just one degree can raise or lower an oil's viscosity as much as 20% while at -20C it could be as little as 1%.
That's why the MRV rating at -40 may have no relevance at temp's as low as -30C in comparing various oils.

That said, M1 0W-30 does have a very low MRV, lower than most 0W-20s, suggesting it's formulated with PAO base stocks.
The latest SN version of M1 0W-40 is GP III based, hence it's much higher MRV. Fortunately we Canadians are still getting the PAO based SM version of M1 0W-40 with a MRV in the 20,000cP range.
 
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