Which Castrol oil for the ///M ?

Robin · Post by **Robin** » Sun 20 Aug, 2006 14:00

I'm taking my car to an indie tomorrow for an oil change.
They use Castrol SLX. I see that according to this, Castrol Edge 0-30 which is recommended for the S50, has replaced SLX, though perhaps the difference between 'Edge' & 'SLX' is miniscule ?
http://www.castrol.com/castrol/productd ... Id=7008887
I'd be interested to know what other ///M owners use.
cheers

montesacota315r · Post by **montesacota315r** » Sun 20 Aug, 2006 15:26

Robin, I too would like to know which oil everyone else is using. Since buying the car i have had an inspection II which my indi carried out using Mobil 1 0w 40, so when i changed the oil last week i used the same.

Phil · Post by **Phil** » Sun 20 Aug, 2006 19:28

My main agent used Castrol Tws
Below is a copy of a previous thread by SpunkyM

The TWS Motorsport and the RS 10W-60 are not the same product.

TWS is tested and approved by BMW to meet the specific requirements for the M series engines - it has a different formulation ( which includes additional synthetic esters ) to the Formula RS 10W-60 to meet the specific BMW requirements and the only spec the TWS meets is BMW.

The EDGE 10W-60 is the retail alternative for the TWS Motorsport, which is a workshop only product supplied to BMW dealers - the EDGE Sport 10W-60 is the alternative to the Formula RS 10W-60 and these do not meet the BMW specifications.

So for the M series asking for the 10W-60 grade, I would recommend either the TWS Motorsport from BMW outlets or the EDGE 10W-60 ( which also only carries the BMW approval ) from retail outlets

Hope that helps

Kind regards

Andy Griffin
Castrol Technical Support

spokey · Post by **spokey** » Sun 20 Aug, 2006 21:28

Phil wrote:So for the M series asking for the 10W-60 grade, I would recommend either the TWS Motorsport from BMW outlets or the EDGE 10W-60 ( which also only carries the BMW approval ) from retail outlets

That's got nothing to do with the fact that TWS costs twice as much as anything else, I'm sure.

I think TWS is only that important in a new M engine, I'm sure an S50 will survive just fine on RS. (But I do know bugger all about it!

)

Robin · Post by **Robin** » Sun 20 Aug, 2006 21:44

Phil wrote:My main agent used Castrol Tws
Below is a copy of a previous thread by SpunkyM

The TWS Motorsport and the RS 10W-60 are not the same product.

TWS is tested and approved by BMW to meet the specific requirements for the M series engines - it has a different formulation ( which includes additional synthetic esters ) to the Formula RS 10W-60 to meet the specific BMW requirements and the only spec the TWS meets is BMW.

The EDGE 10W-60 is the retail alternative for the TWS Motorsport, which is a workshop only product supplied to BMW dealers - the EDGE Sport 10W-60 is the alternative to the Formula RS 10W-60 and these do not meet the BMW specifications.

So for the M series asking for the 10W-60 grade, I would recommend either the TWS Motorsport from BMW outlets or the EDGE 10W-60 ( which also only carries the BMW approval ) from retail outlets

Hope that helps

Kind regards

Andy Griffin
Castrol Technical Support

Thanks for that info. Though I'm surprised you don't mention the 'EDGE 0W-30' as I just spotted the Castrol website recommends that for the S50.
This replaces the SLX. So at one time the SLX was good enough, so that'll have to do as that's whats on offer at the Indie.

SimSimma · Post by **SimSimma** » Mon 21 Aug, 2006 09:09

Hi Robin,

The TWS/RS 10w-60 is for the S54 engines. The 0w-30 is recommended for the S50 although 0w-40 should be fine as well. I think the SLX is an extended mileage/life oil used in the VWs, being changed 15-20k miles. The ///M requires every 7k ish so I wouldn’t buy the SLX as you aren’t making use of its extended life. IMHO buy the 0w-40 RS and change every 3500 miles, runs a lot smoother.

Dan

Robin · Post by **Robin** » Mon 21 Aug, 2006 10:37

Hi Simma
Thanks for that. Things have gone in the direction of the SLX this time. Next time I'll ask them to use Edge 0-30 or 0-40, or change it myself.
R

SimSimma · Post by **SimSimma** » Mon 21 Aug, 2006 10:49

Hi Robin,

I've really noticed a difference in the noise level when changing more regularly, it drops quite a bit with new oil. I tend to do midway between Oil Service and Insp ½ which is about 3500 miles. Maybe because I do a lot of town driving which is more demanding on the oil, with regard to soaking up the acids etc. For the sake of £30 it should pay dividends in the longer term.

Dan

Rags · Post by **Rags** » Wed 23 Aug, 2006 09:48

IMO 0w40 is too thin.

I use 5w40 and some people say that this is too thin.

Oilman put out a bulletin to BMW for the usage of this oil in S50 engines.

10w40 is what Phil Crouch at Birds recommends.

And if you took it to BMW they would probably still insist on 10w60!

Robin · Post by **Robin** » Wed 23 Aug, 2006 10:04

Rags wrote:IMO 0w40 is too thin.

I use 5w40 and some people say that this is too thin.

Oilman put out a bulletin to BMW for the usage of this oil in S50 engines.

10w40 is what Phil Crouch at Birds recommends.

And if you took it to BMW they would probably still insist on 10w60!

Some say thinner oil gets circulates around the Vanos better, but I would say thicker oil is better for gears, I mean gear oil is like syrup & it's the Vanos gears that seem to wear & need replacing. So I really don't know. I mean you could use thicker oil which is good for the Vanos gears, except it so viscous it won't get there in sufficient amounts to do the bizz !
In the end when I collected my car the indie they said they'd used Fuchs oil which they say is what BMW put in the cars in the factory.
I'm not altogether happy with that as a reason & why did they say SLX over the phone beforehand, then use something different. Also they didn't say which Fuchs oil they'd used. So in the end I'm fuched if I know.
There are so many conflicting views. The Castrol chap here says something different to the castrol web site, which yet again is probably different to the owners manual. I reckon the safest bet is Edge 0-30, as recommended on the Castrol website.... but then again is it ???

c_w · Post by **c_w** » Wed 23 Aug, 2006 10:10

Is it possible to get a fully sythentic 10/40 oil?

SimSimma · Post by **SimSimma** » Wed 23 Aug, 2006 13:41

10W-40 is available from Fuchs (BMW approved, not sure which LL01/4 etc), Motul (Not BMW) and Amsoil (Not BMW) and probably a few more in synthetic form.
Rather than looking at the weight of the oil which is generally a good guide, the viscosity is probably more important. Hopefully most of us don’t give our engines a good spanking until normal operating temperature has been reached, so I’d suggest looking at the viscosity at 100C rather than at 40C.
At 100C the oils have the following viscosity (mm2/sec)
Castrol RS 10W-60 22.7
Castrol TWS 24.3
Castrol Edge 10w-60 24.2
Castrol Edge Sport 10W-60 23.5
Castrol RS 0w-40 12.9
Castrol Edge Sport 0W-40 12.8
Castrol Edge 0W-30 12.2
Mobil 1 0W-40 14.3
Amsoil 5W-40 14.5
Silkolene Pro S 5W-40 14.89
Fuchs Titan 10W-40 13.5

So judging by that there isn’t too much difference between the 0/5/10W-30 / 40, and is really dependant on manufacturer.

What I did find in my reading was:
“There are still vehicles that need 3K oil changes, but it's not because the oil goes bad after 3K miles. One example is the Saturn S series. These vehicles have a timing chain system that is very sensitive to clean oil because oil pressure is used as hydraulic fluid to ratchet up the timing chain tensioner. If varnish forms in the timing chain tensioner bore then this system can fail and the chain will become loose and eventually break.”
http://www.nordicgroup.us/oil.htm#5W30%20versus%2010W30

Not sure if I read in a post earlier but the VANOS has a hydraulic mechanism? Maybe it’s not necessarily the grade we use, more how often we change. Hence the service indicator of 7k ish between Insp1/2 and oil service, which still might be too high.

Robin · Post by **Robin** » Fri 25 Aug, 2006 17:31

I found out today precisely what the indie put in my car.
Fuchs Titan Super Synth 0-30.
The oil recommended by Fuchs is Titan Super Synth 5-40 for the S50.
I emailed the techical guy there & he said 0-30 is fine.
Winter's on it's way after all & I do mainly short trips.

SpunkyM · Post by **SpunkyM** » Fri 25 Aug, 2006 21:28

This is just my oppinion but a hot 30 grade oil (like a 0W 30) is not going to do your VANOS any favours at all. The contact surfaces and operation of the VANOS is not too disimilar to a gear box, which of course requires a very thick oil to provide protection.

I think it is no coincidence that after all the VANOS problems BMW faced with the S50 engine they specified a 60 weight oil for the S54. At the end of the day the VANOS is not fundamentally different in design - just tweaked slightly (the exact changes appear to be somewhat shrouded in darkness). The difference between a 30 weight oil and a 60 weight oil is huge. I have a feeling that it would cause all sorts of litigation problems if BMW suddenly recommended a 10W 60 oil for the S50 after all this time, and that is the primary reason why they don't.

All I know is that if I had an S50, and my primary concern was prolonging the VANOS life, I would be using a 10W 60 oil as per the S54.

Robin · Post by **Robin** » Fri 25 Aug, 2006 22:18

SpunkyM wrote:This is just my oppinion but a hot 30 grade oil (like a 0W 30) is not going to do your VANOS any favours at all. The contact surfaces and operation of the VANOS is not too disimilar to a gear box, which of course requires a very thick oil to provide protection.

I think it is no coincidence that after all the VANOS problems BMW faced with the S50 engine they specified a 60 weight oil for the S54. At the end of the day the VANOS is not fundamentally different in design - just tweaked slightly (the exact changes appear to be somewhat shrouded in darkness). The difference between a 30 weight oil and a 60 weight oil is huge. I have a feeling that it would cause all sorts of litigation problems if BMW suddenly recommended a 10W 60 oil for the S50 after all this time, and that is the primary reason why they don't.

All I know is that if I had an S50, and my primary concern was prolonging the VANOS life, I would be using a 10W 60 oil as per the S54.

There's logic in what you say. Thick oil for gears is best. On the other hand some say, & indeed the owners manual says, it's important to get the oil temp up to 60 degrees before exceeding 4000 RPM. This is surely to ensure the oil is thin enough to be circulating freely around the Vanos.

Guest · Post by **Guest** » Sat 26 Aug, 2006 09:17

If I remember correctly, BMW only switched to the 10-60 for S54 engines at the same time a few early M3s had big end problems. The stated reason for the big end issues was a bad batch of bearing shells, but they changed the oil grade anyway.

I would follow whatever BMW recommends to the letter. After all, BMW are not going to specify an oil that causes more warranty claims.

Simon

SpunkyM · Post by **SpunkyM** » Sat 26 Aug, 2006 09:25

Think of it like this - all the S54's seem to do very well on the 10W 60 grade, so what reason would you have for not using it in the S50 (apart from BMW's rather dubious recommendations). Mechanically the engines really aren't that much different ( it's just the electronic control of them that is).

Guest · Post by **Guest** » Sat 26 Aug, 2006 10:05

SpunkyM wrote:Think of it like this - all the S54's seem to do very well on the 10W 60 grade, so what reason would you have for not using it in the S50 (apart from BMW's rather dubious recommendations). Mechanically the engines really aren't that much different ( it's just the electronic control of them that is).

BMWs switch to a 10-60 for the S54 must have been done for a VERY good reason. The fact that they didn't switch to a 10-60 for the S50 suggests to me that the two engines are different enough to require a different oil. Money also comes in to it.

Profit made when BMW sell oil to their customers = minimal.

Warranty cost to replace big ends or entire engines due to failure = Massive. Not to mention the CSAT issues.

At the end of the day its your choice, but also your funeral. some of the technicians at the dealerships are Muppets, but the ///M boys in Munich are certainly not. Why try to out-guess them ?

MrMicko · Post by **MrMicko** » Sat 26 Aug, 2006 17:43

I track my M Coupe(S50) a lot and I've been using Castrol TWS 10w60, mainly because it was recommended by other track freaks and local BMW approved its use. No problems, engine runs smooth and vanos gears are only slightly noisy(since I bought the car, 5000miles ago).

But of course, I am also concerned what this "wrong" oil may cause, but I don't know for a fact that it does anything bad.

skinny · Post by **skinny** » Mon 28 Aug, 2006 07:16

I also use Castrol RS 10w/60 in my S50, because i drive hard, recently at the "Ring" the oil temp average was 120 degrees, i think 0w/30 would be far to thin at these temps, we was doing 160mph behind a CL65 AMG Brabus tuned and the oil temp hit 135!

Deano1712 · Post by **Deano1712** » Mon 28 Aug, 2006 09:18

Ive had my S50 for 3 months and the only problem (more of a concern) with it is noise from the front of the engine when the oil gets near 100degrees. The noise is a whine (quite loud esp with hood down) which must be the Vanos. I had wondered whether the Vanos was on its way out but I dont get the characteristic noise on slow down 2000rpm to idle. It could be that the oil is not viscous enough when hot and there is some metal to metal contact going on somewhere. I think I will go for some 10-60 today!
I really cant believe that BMW re-engineered the Vanos for S54 to a sufficient extent to change its lubrication requirements. It would have been far easier for them to change the specified oil. S54 is good on Vanos and S50 is not - if this is just down to the oil then what are we all waiting for?
There may be a downside to using 10-60 in the S50 - perhaps cold start performance is impacted. Anyone got experience of this?

Robin · Post by **Robin** » Mon 28 Aug, 2006 10:07

Deano1712 wrote:Ive had my S50 for 3 months and the only problem (more of a concern) with it is noise from the front of the engine when the oil gets near 100degrees. The noise is a whine (quite loud esp with hood down) which must be the Vanos. I had wondered whether the Vanos was on its way out but I dont get the characteristic noise on slow down 2000rpm to idle. It could be that the oil is not viscous enough when hot and there is some metal to metal contact going on somewhere. I think I will go for some 10-60 today!
I really cant believe that BMW re-engineered the Vanos for S54 to a sufficient extent to change its lubrication requirements. It would have been far easier for them to change the specified oil. S54 is good on Vanos and S50 is not - if this is just down to the oil then what are we all waiting for?
There may be a downside to using 10-60 in the S50 - perhaps cold start performance is impacted. Anyone got experience of this?

The S50 has single vanos, the S54 is double vanos so there are differences engineering wise. I've not heard of an S54 vanos going kapput.
If you rev up in neutral then take your foot off throttle the Vanos whine is noticable on the overun as the engine revs drop down past around 2000 rpm. Both my ///M's had whining/growling vanos for thousands of miles. BMW wouldn't change mine under warranty until it started to growl on tickover. It didn't seem to be affecting the performance up to that point anyway. I think it's just the sound of the gears chattering on the splines.
I had new Vanos a couple of thousand miles ago & the new one is starting to whine a little already.
Provided you've had the longer bolts fitted on recall, to hold the cover on under the extremely high oil pressure to the Vanos, then you won't wind up with catastrophic failure with oil flooding out. Any BMW main dealer can check on the data base to check this on your car's history.

SpunkyM · Post by **SpunkyM** » Mon 28 Aug, 2006 10:43

The S50 has single vanos, the S54 is double vanos so there are differences engineering wise

..are you sure Robin? After all, it's only 4bhp different. Are you not getting mixed up with the American spec S52 which had much less power.

Robin · Post by **Robin** » Mon 28 Aug, 2006 11:09

SpunkyM wrote:
The S50 has single vanos, the S54 is double vanos so there are differences engineering wise
..are you sure Robin? After all, it's only 4bhp different. Are you not getting mixed up with the American spec S52 which had much less power.

I was going by what someone said on this forum a couple of months ago. However now I realise they were wrong about S50 being single vanos, judging by this. So thanks for pointing that out Spunky:
http://www.bmwmregistry.com/model_faq.php?id=16
"The European-spec powerplant, known as the S50 B32, is a much more exotic unit. With a bore of 86.4mm and a stroke of 91mm, the S50 B32 has a total displacement of 3,201cc. Like the S52, it has an iron block and aluminum head with four valves per cylinder. However, the S50 B32 incorporates the following special features to allow it to produce an impressive 321 hp (DIN) at 7,400rpm and 258 lb/ft of torque at 3,250 rpm:
-Individual throttle plates for each cylinder
-Increased compression ratio to 11.3:1
-Advanced BMW/Siemens MSS50 engine management system able to compute 20 million instructions per second
-Double VANOS continuously variable valve timing on both intake and exhaust strokes
-Lightweight pistons
-Dual-mass flywheel
-Graphite-coated conrods
-Larger inlet valves
-Second oil pump
What are the differences between the S50 and S54 engines?
The S54 powerplant of the later M coupes is technically an evolution of the iron-block S50 B32 unit used in all European-spec M coupes built through June of 2000. Although the peak power and torque of the S54 (325 hp at 7,400 rpm and 261 lb/ft of torque at 4,900 rpm) are barely increased compared to the S50 B32 (321 hp at 7,400 rpm and 258 lb/ft of torque at 3,250 rpm), they share few major components and differ in many areas including:
-Increased cylinder bore to 87mm (from 86.1mm) for a new total displacement of 3,246cc (from 3,201cc)
-Modified camshafts
-High pressure Double VANOS continuously variable valve timing system with faster operation at high rpm
-Increased compression to 11.5:1 (from 11.3:1)
-More advanced BMW/Siemens MSS 54 engine management control
-Finger-type rocker arms for reduced reciprocating mass and friction
-One-piece aluminum head casting for lighter weight
-Scavenging oil pump to maintain pressure during heavy cornering

The S50 B32 unit can be identified by the "BMW M Power" inscription on its cam cover, while the S54 version contains only the "M" badge."

Guest · Post by **Guest** » Mon 28 Aug, 2006 11:30

Deano1712 wrote:I really cant believe that BMW re-engineered the Vanos for S54 to a sufficient extent to change its lubrication requirements.

They didn't. THe change on oil specification was done following a series of big end failures in the E46 M3. BMW blamed the failures on a bad batch of shells, but also changed the oil and reduced the rev limit.

Although BMW have stated that the ///M roadster with the same S54 engine does not have the same bearing issues due to a lower rev limit to begin with, the S54 ///M roadster has also had a change in oil spec to the same 10w-60 a the M3.

Interestingly, Castrol ( who are usually in tune with BMW ) specify the S50 ///M Roadster as requiring 0W-40 for 1996-1998 models and 0W-30 for 1998-2000. - www.ew2.lubesinfo.com/login.asp?sc=1156

If It seems important enough for Castrol to note a minor spec change for the same engine based on the year then maybe it is for owners too?

The best person to ask would be oilman. Come to think of it, I am sure he has explained this before on another forum. I'll see if I can find it.

Simon

Deano1712 · Post by **Deano1712** » Mon 28 Aug, 2006 11:55

Its sounds like we are agreed then the Vanos is similar

. The whining noise that I get only happens when the oil gets hot and I hear it when I am motoring, particularly mid range. It seems to me that the oil may not be viscous enough to lubricate when its hot. This would cause wear and progressive deterioration of the Vanos. As an engineer

I know that gears/splines will wear when the oil film thickness gets too thin - less that the surface roughness of the material. If there were no lubrication problems with Vanos there would be no wear and we wouldn't be discussing it here. 10-60 has twice the viscosity of 0-30 so it will be much better on the Vanos. The downside for sure is 10-60 will be very thick in winter and the starter may struggle to crank the engine during cold starts. Does the S54 have a more powerful starter motor for this? Using a 10w-60 in the summer and 0-30w in the winter could be the answer for S50.

SpunkyM · Post by **SpunkyM** » Mon 28 Aug, 2006 12:48

The downside for sure is 10-60 will be very thick in winter and the starter may struggle to crank the engine during cold starts

..that really will not be a problem. The physical resistance of the oil (even when very cold) will be negligible at startup as it's such low rpm when cranking.

Interesting point about the bearing shells though. I thought that the 10W 60 was always the recommendation for the S54 - not just after the bearing shell issue came to light. I suspect there is more to it than that though as no oil in the world would have stopped that problem occuring as it was due to a batch of faulty shells (hence only certain manufacture dates and is not an issue with the replacement items). I am still of the oppinion that the gearbox like contact pattern of the VANOS requires a high viscosity oil (not unlike a gearbox). A 60 grade makes sense. As has been proved before on the forum though, I have a feeling this debate will never end

Robin · Post by **Robin** » Mon 28 Aug, 2006 13:06

Deano1712 wrote:10-60 has twice the viscosity of 0-30

Not as much as twice the viscosity. Main difference is it maintains the viscosity over a wider temp range. Also I'm not convinced the S54 Vanos is the same as the S50 Vanos.

SpunkyM · Post by **SpunkyM** » Mon 28 Aug, 2006 14:05

They are subtely different for sure, one item to dissapear on the S54 VANOS was the small thimble style oil filter, I'm sure there are other tweaks too.

But the way the VANOS gears mesh with the cam i.e. the mechanical operation is the same. Some good tech on the VANOS here... viewtopic.php?t=8960&highlight=