Jase

What's wrong with using the oil a Subaru garage supplies as part of a service, is it rubbish? is it the cost? does anyone have the viscosity details on Shell Ultra 5w/40?

I have a 20k service due in March on my STi8 and need to know if it is worth getting my order in now for some Motul or Silkolene 5w/40 oil.

oilman

iTrader: (9)

Nothing other than the Silkolene and Motul are ester based synthetics and far better than the Shell one to be frank.

Cheers
Simon

Andrew Timmins

Could you explain why you are against the 0W oils in a little more detail please? If the viscosity is similar at operating temperature and would be thicker at lower temperatures, though not as thick as say a 10W, how is it offering less protection?

Dark Blue Mark

Just my thoughts, but the upper end of its operating range isn't what concerns me. I would be more concerned about the wear seen on startup from cold, and on its way up to operating temp.

The Castrol RS 0W stuff is like water when you pour it, and I would bet that the wear it allows when cold wouldn't be ideal. This is where something a bit thicker would help, but too thick is equally a problem.

Thin is ok to a point, as a thinner oil at cold will be more free to travel round the engine / turbo areas. Its not exactly cold here compared to a lot of places, where thin oil may be more justified. I would prefer a 5W or 10W in these temps, even though im using 15

Just to clarify - thinner is better on cold start - but too thin promotes more wear IMHO.

MB

oilman

iTrader: (9)

Sorry, I must learn to qualify my statements, here is some data.

Low pour point = good
High Flash point = good
High VI Index = good............as long as
High HTHS = good
Low Noack % = good

I.E. If the VI Index is high and the HTHS/NOACK number aren't good then the oil is not so shear stable or volatility is poor.

Some 5w-40 comparisons

Name................................Flash......Pou r....VI Index...HTHS...Noack

Silkolene PRO S...................195.......-51......169.........4.07.....6
Motul 300V.........................216......-36.......176.........4.51....7
Motul 8100.........................228......-39.......173.........3.92....10
Fuchs Titan Supersyn SL.......240......-39.......162.........3.90....10
76 Lubricants......................232......-42.......175.........3.80....13
Shell Helix Ultra...................207......-36.......187..........2.90....13
Valvoline Syn Power.............238......-37.......159..........2.90....13
Chevron Supreme................222......-49........158.........2.90....13
Esso Ultron........................220......-39........175.........3.60.....12
Mobil Synt S......................220......-39........175.........3.60.....12

Note: A Noack percentage of 13% is the maximum allowed to pass ACEA A3.

Cheers
Simon

Andrew Timmins

Thanks for the quick reply.

If the oil is as thin as water when you pour it in how much thinner must it be at operating temperature?

As the oil is at its thickest when the engine starts then thins with increasing temperature why would a 0W-40 cause more wear than a 10W-40? You would get better oil flow from startup with 0W-40 then they would be a similar viscosity once the engine was up to operating temperature.

The only problem I can see with a 0W oil is if vast quantities of viscosity improvers need to be used and then the oil goes out of grade after a few thousand miles. Knowing the properties of the oil after it has been in the engine for a year would be much more useful than the specification when it was new.

Dark Blue Mark

See Simon's quote form page 3 :-

"I would suggest (as I have on many occasions) that 5w-40 is the best grade giving better cold start than 10w but remember they are all SAE 40's when hot.

5w will in the main will guarantee you a better quality of oil as this formulation is difficult with petroleum oils (therefore at least some if not all synthetic) unlike 10w which can be formulated with 100% hydrocracked oil.

I'm not saying that 15w-50 should not be used and in some cases it may be appropriate but there are more advantages to using a thinner oil in an "all year round" scenario.

Good feedback here by the way. Oil debates - my favorite

Cheers
Simon"

Dark Blue Mark

The viscosity grade (for example, 5W-30) tells you the oil's thickness, or viscosity. A thin oil has a lower number and flows more easily, while thick oils have a higher number and are more resistant to flow.

A 0W is thinner than a 15W

MB

oilman

iTrader: (9)

One small point.

ALL 0w oils are proper fully synthetics (no hydrocracked) as they need to meet or exceed the API -35 degC pourpoint therefore containing PAO or ESTER or both will make them shear stable oils. This will mean little or no VI Improvers.

Cheers
Simon

Andrew Timmins

So why are they considered too thin by many here who then go on to recommend a 5W-40 or 10W-40? Mobil 1 meets the BMW, GM and VW long life specs so must be capable of offering protection and staying in grade over a long period of time.

oilman

iTrader: (9)

Indeed it is or they are.

It's the old hang up I'm afraid and I've never been an advocate of "thick" oils (my many posts testify) as it's an out dated notion that goes back to mineral oils. There is nothing wrong with 0w and 5w oils.

If I had a tenner each time I read or heard the statement "synthetic oils are too thin" I'd be able to retire

Sad though it is, people are influenced by mis-information and the internet is one of the main culprits.

Besides, what always gets me is how people ignore their handbook and manufacturers recommendations..........it's not clever really!

Cheers
Simon

JohnD

iTrader: (5)

[QUOTE=oilman]Nothing other than the Silkolene and Motul are ester based synthetics and far better than the Shell one to be frank.

Cheers
Simon[/QUOTE

Millers CFS 10/40, 10/60 and 15/60 are now "3 ester based" according to their tech. info.
Millers do a full range of road, competition and classic oils in just about any grade you could wish. Take a look www.millersoils.co.uk
With all respect to Motul, Silkolene etc there are other oils of this ilk out there?
JohnD

oilman

iTrader: (9)

Slight misquote or misunderstanding there:

Original question:

My reply was as follows:

Nothing other than the Silkolene and Motul are ester based synthetics and far better than the Shell one to be frank.

My reply was that there was nothing wrong just that there was better out there.

Yes Millers quote ester and they probably do use a small percentage but they will not disclose what %, trade secret apparantly. Silkolene Pro and Motul 300V are around 20%. Not sure what Millers have to hide.

Cheers
Simon

JohnD

iTrader: (5)

Refering to Oilmans last post Re-thick/thin oils I've been around cars for a few years now (err - like 42 yrs of driving!!) and I've been through the various oil "periods" eg Castrol XL, XXL Castrolite, Duckhams Q20/50 (bright green!) and now the synthetics. So I've used monogrades thro' to multigrades, so it would be almost excusable for me to be stuck in the past when oils were thick and oil pressure lights took 5 seconds to go out! (accompanied by strange knocking and rattle sounds) Fortunatly I'm certainly not stuck in the '60's (It was a great time though!) Like he said, there is a notion that thick is best, but consider : A bearing with a total clearance of say .025mm will only take that much oil whether it's thick or thin, the difference is that the thinner oil will FLOW faster under pressure through the bearing. So, as long as the thinner oil has adequately high load bearing and shear stress properties and the oil pumps fine, I see nothing but good? There is a limit of course, so don't go putting 3 in 1 in the sump!
On the other hand at my age senility may have set in and I'm talking a load of old b****cks!
JohnD

oilman

iTrader: (9)

I know I've posted this before but worth a refresher:

Surely the thicker the oil the better!

This isn't always true - even when using a petroleum oil. Although it is true that
heavier viscosity oils (which are generally thought of as being thicker) will hold up better under heavy loads and high temperatures, this doesn't necessarily make them a better choice for all applications.

On many newer vehicles only 0w-40, 5w40 or 10w40 engine oils are recommended by the manufacturer.

If you choose to use a higher viscosity oil than what is recommended, at the very least you are likely to reduce performance of the engine. Fuel economy will likely go down and engine performance will drop.

In the winter months it is highly recommended that you not use a heavier grade oil than what is recommended by the manufacturer. In cold start conditions you could very well be causing more engine wear than when using a lighter viscosity oil. In the summer months, going to a heavier grade is less of an issue, but there are still some things to be aware of.

Moving one grade up from the recommended viscosity is not likely to cause any problems (say from a 10w40 to a 10w50 oil). The differences in pumping and flow resitance will be slight. Although, efficiency of the engine will decrease, the oil will likely still flow adequately through the engine to maintain proper protection.

However, it will not protect any better than the lighter weight oil recommended by the manufacturer.

Moving two grades up from the recommended viscosity (say 10w40 to 10w-60) is a little more extreme and could cause long term engine damage if not short term.

Although the oil will still probably flow ok through the engine, it is a heavier visocosity oil. As such it will be more difficult to pump the oil through the engine. More friction will be present than with a lighter viscosity oil.

More friction means more heat. In other words, by going to a thicker oil in the summer months, you may actually be causing more heat build-up within the engine. You'll still be providing adequate protection from metal to metal contact in the engine by going with a high viscosity, but the higher viscosity will raise engine temperatures.

In the short run, this is no big deal. However, over the long term, when engine components are run at higher temperatures, they WILL wear out more quickly.

As such, if you intend on keeping the vehicle for awhile, keep this in mind if you're considering using a heavier weight oil than the manufacturer recommends.

Just some food for thought.

Cheers
Simon

Dark Blue Mark

So all us 15W50 Motul users are all misguided then?

MB

oilman

iTrader: (9)

No but if the Motul 300V 5w-40 is good enough for the Subaru World Rally Team, it should be more than good enough for road going cars.

Just my humble opinion, I'm sure many will disagree.

Cheers
Simon

New_scooby_04

iTrader: (4)

ARGH!! My brain hurts, I was so confident in my use of Silkolene Pro S 10w 50... on my MY99 now I don't know *sobs* :-)

oilman

iTrader: (9)

Pro S 10w-50 is better than a 15w-50 as it has better cold start so I wouldn't worry.

Cheers
Simon

Fuzz

what do they recommend for the later model classic shape scoob turbo?
Last time I looked I think it was shell Helix, has this been superseded.

What in your opinion Simon would you use?

P.s I wont be on your case if it goes pop.

Andy

Fuzz

Do the specs for the Motul300V stand for both the 15-50 AND 5-40 versions

Any specs on the Mobil 1 Motorsport variety?


Cheers
Andy

oilman

iTrader: (9)

Fuzz,

Which year, model and engine?

Cheers
Simon

Fuzz

00MY quad cam turbo (turbo 2000)

oilman

iTrader: (9)

I'd say 5w-40

This should help

Checked with the following:

Silkolene Technical Department
Motul Technical Department
OATS - The largest proprietory oil recommendation database in the UK.

And, these were the recommendations that I recieved from them:

Impreza 2.0i Sport 1996-00

Motul 5w-40 or 10w-40
Silkolene 5w-40 or 10w-40
OATS 10w-40

Impreza 2.5i 4WD 2001 onwards

Motul 5w-30 or 5w-40
Silkolene 5w-40
OATS 5w-30 or 5w-40

Impreza 2.0i WRX/STi Turbo 2001 onwards

Motul 5w-30 or 5w-40
Silkolene 5w-40
OATS 5w-30 or 5w-40

Impreza 2.0i Turbo 1994-00

Motul 5w-40 or 10w-40
Silkolene 5w-40
OATS 10w-40

Impreza 2.0 4WD 2000 onwards

Motul 0w-30, 0w-40, 5w-30 or 5w-40
Silkolene 5w-30 or 5w-40
OATS 5w-30 or 5w-40

Impreza 1.6i, 1.8i 4WD 1993-96

Motul 5w-40 or 10w-40
Silkolene 10w-40
OATS 10w-40

What would I use? Well with no expense spared, Silkolene or Motul

Cheers
Simon

Dark Blue Mark

Simon, do they use a thinner grade to gain BHP? Is it really 5W 40 or a modified form of it?

Guess they don't have to considder longeivity of their internals as we do

MB

Vegescoob

I'm gonna change to extra virgin(!) olive oil! It must be good cos it costs a lot and my emissions won't half smell nice.

oilman

iTrader: (9)

Yes they will gain BHP but a shear stable 5w-40 like Silkolene PRO S or Motul 300V will also handle temps up to 130 degC. The oil is not modified.
A good 5w-40 will look after your "internals" without a problem so long as you observe the recommended drain periods.

Cheers
Simon

oilman

iTrader: (9)

I asked John Rowland (Silkolene Chief R&D Chemist) for his opinion on the actual differences between 0w-40 and 5w-40 and below is his reply:

Quote:

Simon,

0W/40 oils, even the best, are not very shear stable. Even the top quality ones are based on very thin 2cSt PAO plus a lot of VI improver, so in the long term it is the high temperature viscosity that suffers.

A good 0W/40 will provide good protection on start-up, and it will be better than a 10W/40, but only in very cold conditions. (0W was originally an ‘Arctic’ spec.) A good compromise for all North European climates is 5W/40.

Top quality ones are based on 4cSt PAO, and a smaller amount of more shear-stable VI-improver. ….And remember! The difference between 0W and 5W is not a big deal.

A 0W has to be less than 6200cP at -35C, a 5W less than 6600cP at -30C. Our side of the Arctic circle, the difference isn’t worth bothering about.

John Rowland

Unquote:

Hope this clarifies some of the chemistry involved.

Cheers
Simon

Dark Blue Mark

Thanks Simon good info,

Fits with what I was saying about 0W only being better / benefit in really freezing countries

He / you clearly know more than I as its your core business (and for that reason take their word above mine!), but I still think 0W will promote a bit more wear on start then say a 10W - in our conditions.

Ok, thicker oil will generate more frictional heat, but frictional heat isn't that much of an issuse for the first 0- 10 minutes on a cold day. Therefore with a very thin oil (0W) you are promoting more physical contact of engine internals.

After all, oil is designed to primarily lubricate, and to transfer frictional heat. Id rather oil generating the heat through friction against the internals, than the internals generating heat through decreased oil film.

All IMHO

In the real world im not sure its massively relevant.

MB

oilman

iTrader: (9)

Thanks to those that have voted so far.

There must be more! How many Members here 40000+ :0

Cheers
Simon