Oil explained by a Castrol Tech

[JonnyFoxtrot]

Just found this on one of the R1200GS forums (potentially my next bike ) and thought it might be useful for people.

I take no credit for the info here (its all copied from the link below) and presented here for easy reading.

https://www.ukgser.com/forums/showthread.php?t=91251

Might be helpful to clear up a few myths and stop a few of those oil questions that always pop up a few times a week, provided its a genuine response from Castrol.



Sent: 10 December 2006 22:35
To: Cat, Enquiries
Subject: Help undestanding oil, please

Dear Castrol

I guess you people know all there is to know about oil!

I run a bog standard BMW R1200GS motorcycle.

Oil is always perceived as a bit of a mystery to some of us mere mortals. I wonder if you could help me please?

Hi Richard
Please see replies in bold- seemed the easiest way of doing it

(A) Am I right in thinking that:

(i) Oils with two numbers, 10W-40 for instance, are known as multi-grades? yes, that's correct - roughly translated means it acts like a 10W oil when cold, and a 40 when at working temperature.

(ii) That multi-grades have been developed to run in an engine operating across a reasonably wide temperature range? For instance that the lower number of the two numbers means that, when the engine is cold, the oil behaves like a 10 weight but then, when the engine is hot, the selfsame oil behaves like a 40 weight oil? Spot on - different engines will have different viscosity recommendations for different ambient temperatures though - always refer to the handbook for recommendations on specific applications.

(B) I have noticed that when I am in the south of France, where the weather hotter on average than it is here in the UK, the oils on sale generally have slightly different numbers than those I trip over in the garage at home. I guess this is because the southern French do not need the lower number to be so low (it's generally warmer) but do need the higher number to be higher (as the air and operating temperatures are generally warmer). Is my conclusion correct? I guess it is, simply because I see the numbers changing as I ride back up through France, with the oil in Calais, by and large, carrying the same numbers as UK oil. Again - correct, although you could argue that the thinner the oil when cold, the quicker the oil will circulate round the engine and build up a protective hydrodynamic oil film, giving faster protection to the engine components . would expect probably a 10W-40 / 15W-50 oil in France - but would still suggest a 10w-40 would be perfectly suitable for most applications up to 40º ambient

(C) In the very hot summer we just enjoyed, would it be a good idea to move from a 10-40 oil to, say, a 15-40 or 20-50 oil? Or can I simply leave it? I see that the average day time temperatures in the summer, despite the hot weather, were still within the 10-40 band, even if the hottest part of the day were outside of the 10-40 oils recommended band. I guess one does not need to be exact and carry a thermometer and oil change around, ready for every hot spell? Sort of - if you look in the BMW handbook it has a chart of different viscosity ratings for different ambient temperatures - the largest temperature range seems to be covered by a 15W-40 / 20W-50 engine oil. BMW tend to prefer basic mineral oils and I have heard very good reports about castrol GTX High Mileage 15W-40 which is what I normally recommend for the BMW's

(D) As I understand it, it is OK to mix oils with different weights? Yes, although it will obviously effect the viscosity of the oil

Here is an extreme example of what I mean. Let's say I had 10-40 oil in the engine and it was half empty. I think it would be OK to fill up the missing half with, say, 15-50. From what I have read the result would be 12.50 - 45 and be quite OK. - more or less regarding viscosity - wouldn't expect any problems . I can imagine that some of the very extreme numbers may not mix too well? Is that right? However, as I am unlikely to come across some of the industry's more exotic oils at the average motor factors or garage, I guess I cannot worry about that too much? In theory, you could mix a fully synthetic 0W-30 with a mineral 20W-50 ( if we look at the extremes ) and you'd end up with something like a 10W-40 semi synthetic - although we wouldn't really recommend you do this , but in theory it would be fine

(E) Am I right in thinking that:

(i) All motor oils (mineral, semi-synthetic and fully synthetic) all start from the same crude oil base? Yes, although Ester based synthetics are derived from mixing alcohols and acids - these are used as additives, and base oils in some high end synthetics, but most fully synthetic oils on the market will be PAO which are derived from mineral crude, which is why you can mix them ( motor oils generally available that is ) with no adverse effects.

(ii) That the synthetic oils simply carrying more additives than run of the mill mineral oil? Sometimes, depends on the specification the oil needs to meet, but synthetic oils are tailored to do a more specific job so the additive package can be tailored to meet specific needs which could mean more additives are needed.

(iii) The 'fully synthetic' label is perhaps a bit of a misnomer? To me it implies it is fully artificial, suggesting it was made entirely in a laboratory, not from crude oil, then tweaked with man-made additives in the final process. It depends - fully synthetics tend to be classed as lubricating fluids made by chemically reacting materials of a specific chemical composition to produce a compound with planned and predictable properties. think of them as very pure base stocks where the waxes and impurities have been completely removed by chemical process.

(iv) That semi-synthetic oil is simply a mixture of base mineral oil and fully-synthetic oil? yes - that is basically correct

(F) If my motorcycle needed oil, I think is it OK to mix: yes, shouldn't be a problem although we would recommend trying to stick with the manufacturers recommendations where possible as this will give the best performance and protection for your engine

(i) Mineral oil with semi-synthetic oil?

(ii) Semi-synthetic with fully synthetic?

(iii) Mineral with fully synthetic?

(iii) A mixture of all three?

I have no great desire to try just for the sake of it. I simply need to know that it would be OK. yes to all three above - although adding mineral to a synthetic will compromise the benefits, and may reduce the specification below that which is required for the vehicle, especially if a fully synthetic oil is required

(G) Am I right in thinking that it is OK to mix oil from any of the recognised decent manufacturers? Castrol with Valvoline or Esso with Morris, for instance. - yes, if the oil is the same spec then no problem - if different spec then rules above apply - obviously, sticking with one brand is preferred, that way you are sure the additive package is not compromised by any slight differences between manufacturers.

(H) Whilst I think I understand the above, I am still confused by the other letters that seem to appear on the can. I think they apply to different countries' official ways to measure the quality of oil and / or refer to some additives that may be mixed in. Is that right? Do you have an idiot's guide? . https://www.carbibles.com/engineoil_bible.html some good general info here - not anything to do with Castrol, but useful none the less.

(I) Am I right in thinking that motorcycles with wet clutches should not be run on oils specifically designed for cars, as the oil may be too slippery, leading to clutch slip? It's not a problem, I guess, if the motorbike has a dry clutch? General rule of thumb is yes - we get people saying they have used GTX Magnatec with no problems, but we are all bikers here and we all use bike specific oils as they protect the engine and gearbox and allow the clutch to perform properly. Car oils are designed for car engines and can cause clutch slip and early gear wear..

(J) Am I right in thinking that, as the good old BMW flat twin is not a particularly high revving engine (unlike say a Honda 600R, going up to perhaps 17,000 RPM) there is no great need or advantage in using anything better than decent semi-synthetic oil, once the engine is run in. BMW seem to recommend mineral oil for at least the basic running in period 600-1000 miles and, apparently, up to about the next six thousand miles (some dealers say 10,000). I'd say that is a good rule of thumb - BMW engines tend to take a long time to run in ( 10K ) and if not done properly can tend to burn oil later on - BMW specify a basic mineral, although many dealers use a semi synthetic as a service grade

(K) Is the old joke, "Any oil is better than no oil", near enough true? yes, but the "right oil" is always better than "any oil"

Many thanks for any help you can give me.

Hope the above helps

Kind regards

Andy Griffin
Castrol Technical Support
____________________
'89 Honda NS125F (SOLD) -> '92 Suzuki GS500E (SOLD) -> '03 Kawasaki ZX6R B1H (SOLD) -> '96 VFR 750 RC36 (SOLD) -> '02 Honda CBR1100XX Blackbird

[JonnyFoxtrot]

And from the same forum but a different thread (they seem to be a bit oil crazy there ) is a response from Opie Oils on recommended oils from the dealer. Although it might not directly apply to everyones bike (we ain't all got R1200GS's after all!) I'm sure it probably applies to what most dealers are telling people so beware

https://www.ukgser.com/forums/showthread.php?t=239140



Just thought Id share a couple of email conversations I had with Opie oils, this was prompted by a request for their recomendation for a 1200GSA. I then discussed with them the data sheet on Mottorads site with BMW speak!!

I bust my chops to be able to afford this bike and am pee'ed off with this constant attempt to milk me further

From: Ian Ransom [mailto:ipr4@le.ac.uk]
Sent: Thu 05/08/2010 15:44
To: Opie Oils
Subject: Opie Oils - Recommend an Oil


The following enquiry was made from the Opie Oils Contact Form:

Name: Ian Ransom
Telephone: 01526345788
Email: ipr4@le.ac.uk

CAR / BIKE DETAILS

Customer checked WOPR?: NO
Make: BMW
Model: R1200GS
Year: 2009
Engine Type: Petrol
Engine Model:
Modifications:
Driving Style:
Additional Information:
From: Opie Oils [sales@opieoils.co.uk]
Sent: 05 August 2010 15:26
To: Ian Ransom
Subject: RE: Opie Oils - Recommend an Oil


Hi Ian

You need a 15w-50 oil and our selection is below

https://www.opieoils.co.uk/c-784-15w-50.aspx

The Silkolene Pro 4 and Motul 300V are two of the best oils on the market, but as a good value day to day oil, the Motul 5100 is a good choice.

Regards

Tim

OPIE OILS

From: Ransom, Ian P. [mailto:ipr4@leicester.ac.uk]
Sent: Thu 05/08/2010 16:17
To: Opie Oils
Subject: RE: Opie Oils - Recommend an Oil


Hi
SOrry to be an anorak but I found the attached file on BMW web site if your users are to keep within the bounds of warranty then Im afraid
your recomendations are incorrect.

Regards
Ian


Sent: 05 August 2010 16:38
To: Ransom, Ian P.
Subject: RE: Opie Oils - Recommend an Oil


Ian,

Just had a look at that PDF, your bike comes under the boxer recommendation? Castrol/BMW's top choice is for the Castrol Power 1 Racing 10w-50 fully synthetic, this is actually an old oil that Castrol discontinued a few years ago, when BMW introduced the new R1200GS Castrol re released this oil as the preffered choice and is currently only available through BMW dealers (racketeering at its best!) What is interesting is they also recommend the Castrol ACT Evo 20w-50, and this could not be further apart quality wise from the 10w-50 as it is a basic mineral mulitgrade oil. So it spells out to me that the usual scaremongering tactics are in play often seen with BMW and Castrol.

It is against the law to only recommend one specific oil and that it can only be purchased from one place hense the suggestion of the use of the 20w-50 that is readily available. However both BMW and Castrol will scare owners as much as possible that their warranty will be invalid if the 10w-50 is not used. All other reputable bike oil manufacturers are recommending 10w-50, 15w-50 and also 20w-50 for use in the R1200GS.

I would be interested to see what you handbook has to say on this, among the viscosity 10w-50, 15w-50 etc you should see and API specification for the oil that should read something like API SF/SG, are you able to confirm?

Regards

Guy.

From: Ransom, Ian P. [mailto:ipr4@leicester.ac.uk]
Sent: Thu 05/08/2010 20:09
To: Opie Oils
Subject: RE: Opie Oils - Recommend an Oil


Hi
I was out on iphone for my 1st reply. The handbook says API, SF or better or ACEA Class A" or better, according to Wollaston this will be updated!!!
My rsponse was that if it was that critical surely they should hand out a supplement to the handbook at time of sale!!!
Its all crap designed to scare!I will of course be using the cheaper option!

DOnt suppose you can supply the gearbox and final drive oils?

Regards
Ian

Ian,

Thanks for the confirmation on the handbook specs, as I suspected an API SF or better (using oils that meet these specs or above is what gives the customer freedom to use different oils, and ammo should there be a claim), the ACEA A stands for petrol, usually there will be a number after it so it will read like ACEA A3. As a point of interest ACEA B# stands for diesel.

For the gearbox and final drive you can use the same oil, the officialy BMW oil of choice is the Castrol SAF-XO here https://www.opieoils.co.uk/p-737-cast...lubricant.aspx It is a very good oil, so I would go with it.

Regards

Guy.

OPIE OILS
____________________
'89 Honda NS125F (SOLD) -> '92 Suzuki GS500E (SOLD) -> '03 Kawasaki ZX6R B1H (SOLD) -> '96 VFR 750 RC36 (SOLD) -> '02 Honda CBR1100XX Blackbird

[JonnyFoxtrot]

Lastly, not trying to teach anyone to suck eggs, so feel free to skim and ignore if its not useful.

I've got some of our less informed folk in mind here
____________________
'89 Honda NS125F (SOLD) -> '92 Suzuki GS500E (SOLD) -> '03 Kawasaki ZX6R B1H (SOLD) -> '96 VFR 750 RC36 (SOLD) -> '02 Honda CBR1100XX Blackbird

[Raffles]

[map]

Interesting as thet was about the 1200GS.
Was chatting to a friend at Squires about his GS.
He was saying that BMW specify a specific oil that you can't just get around the corner shop. Sadly I did not press him on this for more info.

Anyhow he said the GS does burn oil. However given the engine design I doubt it'll be just the GS model. He has a 1/3 litre bottle strapped inside the front fairing (near forks). Apparently it is a standard accessory (his bike has a lot of Touratech anyhow).
____________________
...and the whirlwind is in the thorn trees, it's hard for thee to kick against the pricks...
Gibbs, what did Duckie look like when he was younger?

[Thelostone]

Interesting that the guy from Castrol wrote "...most fully synthetic oils on the market will be PAO..." when you consider the lengths Castrol went to to be able sell their hydro-cracked stuff as if it was PAO.

Is this just marketing double-speak or is Castrol "synthetic" oil now PAO? I suspect the former but does anyone actually know?

[weasley]

[NeiljohnUK]

You can keep that BMW Castrol crap, my F650GS (800 twin) rattled like a b'stard after a 20 min fast run at 70 on it at 1500 miles, changed to Motul 10-50 synth and 3000 miles on it's still quiet, perhaps most of the F800 piston slap problems are down to overly thin oil???

As I work as a tribologist as part of my job and read a lot of oil/lube info, the Mercans picked up on the trend to use ultra thin oil in some countries, but not in others, to suit fuel consumption testing of NEW engine's, thin equals less hydrodynamic drag, but increasing wear due to too thin a film. So the bottom line is does the oil still work when hot and really thin, when film strength is really important, if not then something better may well bge required!

SWTSMBO's Fiat engined Suzuki built Vauxhaul Agila diesel has very thin synthetic oil and it's supposed to last 30,000 miles! I'm not convinced...