Having started and then followed this debate with great interest, and I'm not the Author of the original post, he has forgotten more than I know about engine oils and the benefits/downsides of the different grades and types in a wide range of cars.

The above post and particularly this statement is probably the most informed I've seen here (no disrespect to others).

It does seem to me that using 10w-60 and that is what this debate has narrowed down to is not the right choice IMHO.

There are many questions that Subaru owners should be asking but these are perhaps the most pertinent ones:

1) Why am I using 10w-60 when it's not listed in my handbook?

2) Will it damage my engine long term?

I think I can answer number 2) only you can truly answer 1)

I don't think that it will damage your engine but it certainly will not be as good for it as using the correct grade whether it be 10w-40, 10w-50 or 15w-50 as manufacturers don't recommend oils for no reason. Engines are tested on different oils to identify the optimum performance and protection.

With regards to posting the original article, I felt it was both informative and of interest to all Subaru Owners as it is written by a very experienced R&D Chemist who is not a marketing man so there is no hype, just factual information that's not available in the marketing brochures. I've read many oil related threads here and on other Forums but the biggest problem is it's always about what people think is best, not necessarily what is best.

In answer to Bob's statements about Silkolene (and of course a man of his experience is entitled to his views) I contacted John Rowland to ask for him to respond so, here it is.

Quote:

Simon,

Ask our rally expert Tom Watson about this. It is true that ‘extreme’ or poorly set up anti-lag turbo systems generate a lot of heat, and dilute the oil, so in such cases Pro-R 15W/50 ( a superior equivalent to Motul 300V) or Pro-S 10W/50 are a good idea. But there are plenty of WRC cars out there winning on Pro-S 5W/40.
JR

Unquote:

I know, what some will say next "he would say that wouldn't he" and I suppose to some extent it's true but read the following and it does somewhat back up his statement.

Quote:

From: Tom WATSON [info@x-cite2000.freeserve.co.uk]
Sent: 07 May 2004 16:16
To: Rowland, John
Subject: Peugeot Cosworth - result!

John

Just a note to let you know I've heard from Andy Burton - the rally driver with the 300+bhp Peugeot-ice-racer-bodied hybrid with the normally asthmatic
Cosworth in the back.

Prior to you taking over, he used to have to strip the engine after every event (normally 45 miles, he couldn't get it to last for a National event of 70-80 miles) and change the big end bearings every time.

He'd been everywhere and tried everything (including Halfords!), and couldn't solve his problem.

First off, he was really surprised when you asked to look at the bearings, as
no-one had ever asked! He was equally surprised by your recommendation to go thinner, and also, I have to say, worried. He equated 'thickness' with 'better protection'.

I eventually persuaded him to try Pro S 5w/40, as you suggested, but I couldn't get him down to the 0w/20.

He called me to say he'd stripped the engine this week, after it's FOURTH event (approx 200 competitive miles!), and there isn't a mark on it. He is utterly delighted, and asked me to pass on his thanks for all your help and expertise.

I'd also like to add my thanks to you. He is extremely influential in
competition circles, and is now going to tell the world and his wife what, and
who, sorted this problem.

Once again, many thanks
Regards
Tom W

Unquote:

As regards to the comments about my business, If I haven't stated it clearly enough, I sell oils by Castrol, Mobil, Silkolene, Fuchs and Total. This includes Castrol 10w-60!

If anyone would like advice or to comment "off forum" then please feel free to get in touch with me at sales@opieoils.co.uk and I will do my best to answer any of you questions. If the handbook recommendations could be emailed to me at the above I would be most grateful and will study them in depth.

Cheers
Simon

 

I'm confused now...

I'm pretty sure that you *invalidate* your warranty in Belgium/The Netherlands if you don't put Castrol TWS 10W60 in your E46 M3.

Ah, found it:

That said, keep up the posting, it's good to see this stuff challenged

 

The above being castrol 10w60rs

I'm not going to quote the certain green book this is from (In case of locked threads and copyright), but the car is a lightly modded legacy liberty rs (Aussy i beleve ej25)

I'll take the 6200rpm peak power line. (All in bhp)

Mobil 1 5w-50 304.3
shell helix ultra (recomended by subaru in the manual for my99 uk turbo) 5w-40 303.5
castrol 10w-60r 306.5
amsoil 10w40 305.6
mobil 1 0w40 311.2
royal purple 308.7
bp visco 5w40 303.6
castrol slx 0w30 305.1

taken at controlled oil and water temperatures.

personally i find 10w60 makes the engine sound a bit rattley when cold so don't use it.
10w 50 would be my choise but i don't know which maker to choose.

i also wouldn't use a 15/50 given i make a lot of short runs.

dave

 

I am aware of the recommendation of 10w-60 Castrol for certain (very limited) applications on BMW's. This is a major "about turn" when you consider that 5w is the most commonly recommended grade for the majority of BMW's for "all year round" use.

I'm not saying it's wrong but it's a big difference from the generally recommended viscosity.

Cheers
Simon

 

Fair enough.

Would it make more sense to you when people take their cars on track regularly ?

 

It would make it more logical but for everyday driving - no!

Cheers
Simon

 

right, so am i to draw the conclusion that you don't recommend 10w/60 for general driving conditions oilman? but if the car is a regular on the track it's ok to use?

i've bought the RS 10w/60 on recomendation of a good QUALITY oil, i didn't take into consideration how much difference there is in viscosity and if that is suited to my driving enviroment.

i keep harping on about it, but is this the right oil grade for my car given the sort of driving i do? (short runs of approx 4 miles and weekly 'blasts')

i'm just wondering as to why the generaly 'approved by scoobynetters' oils seem to be a higher rating than the 10w/40 recomended by the book? ie 15/50 or 10/60?

 

Simple it's a mix of drivers. The ones that shout the loudest and know what they are talking about are enthusiasts, they are the ones who normally drive the car to it's limit, are heavily into modifying and do tracks days etc. So they choose an oil suitable to their needs on their own knowledge.

However on SN, one side of the users have the people who thrape the nuts off the things, or mod them to high heaven,or blast 100 miles up the motorway everyday.

Then you get the ones who have un-modified cars, or do 3 or 4 cold starts a day, or drive a maximum maximum of 10-20 miles a day, or never ever goes above 70mph.

Different drving situations require different types of oil. The previous would require a oil that maintains a sufficient viscosity at very high temperatures (15w-50 or 10w-60). Whilst the latter would require oils with good cold start protection, and don't need such high temperature viscosity stability (10w-40, 10w50 or 5w-40).

 

****, looks like i've dropped a bollock again

would my car run hotter or require this thickness of oil as it's been mapped (tek2 on a ukMY99) do you think?

 

Ali-B is right in what he says, different cars and styles of driving have different needs and driving around everyday on 10w-60 (regardless of my thoughts) is just not the right thing to do if the car requires 10w-40.

You could consider a 10w-40 fully syn or even semi or a 5w-40 for better cold starts or even a 10w-50 or 15w-50 for enthusiastic driving including track days (especially if you use an ester one which is "shear stable") but to step up as far as a 60 is as I've said before a step out of grade too far.

If you really want to know the best oil for you grade wise (nothing to do with brands as that's a personal choice) then I can and am willing to help.

Email me the relevant page in your handbook and I'll give you your best options with absolutely no obligation. Just remember to mention if you have modified the engine please as it will allow me to recommend more acurately.

It's really personal taste but let's face it, some oils are "in vogue" and I suspect that many people use them for this reason not because they're technically correct.

Cheers
Simon

 

Simon

Regards Question 1) Some of the guys on here are producing over double the original BHP and torque using standard size components (bearings)
This is way in excess of the loadings seen by a 300 bhp NA car which on a good day will see 200 lbft torque. Even the WRC cars are pegged at just over 300 bhp due to the restrictors.
We are talking about 550+bhp and 500+lbft of torque on a bearing that is considered marginal on the std output.
I know at least one guy who has sucessfully run Royal Purple low viscosity oil on his 500+bhp Impreza without issue but I have to say I have my reservations about going thinner.
Can you or John Rowland offer any technical information to convince me it is safe or even beneficial to use lower viscosity ?

Andy

 

Andy, I'll get back to you as soon as I hear but with the figures above the most important aspect of your oil selection must be "thermal stability" when the engine is running hot therefore whatever your choice, you must seriously consider a quality oil (ester/pao would be best) which is "shear stable".

Remember the "surface-active" qualities of ester will look after the "boundary" lubrication.

Cheers
Simon

 

It's interesting to hear the concerns of those using "thick" oils such as Castrol RS 10/60 as I (and I'm sure quite a few others out there) bought a 4x4litres box from Castrol at a good price a while ago.
If you are concerned (as I am) that 10/60 is indeed a bit thick for say, winter use, then could we have an opinion from a well informed source of the viability of mixing say, a litre of the RS 0/40, with 4 litres of RS 10/60 to reduce the viscosity?
Are these oils based on the same formulation, and if so, would mixing as stated cause any reduction in the oils capabilities? If a 1:1 mix produced something around 5/50 (although I suspect it's not as simple as that chemically?) that would be a good compromise grade!
Has anyone else considered this option?
Opinions from the chemists please?
JohnD

 

JohnD,

Rather than take the risk of one formulation screwing up another, I would choose the grade you want and just replace it. You will have wasted something like 2 .75 4litre containers?

BUT. You still have to decide on which oil to replace it with - a decision that much thought is put into by many people and to which there are no straight answers.

I have replaced my semi synthetic Shell oil with RedLine 10W-40. The grade is comfortably within the limits of the manual - given I have a standard car. The car has never been quieter or smoother but this is the first time I've used fully synthetic oil. I am currently locating a good lab so as to analyse the oil I took out to see if had any life left in it and will do the same when I change the oil at the next service. At least this way I can be sure of running on good oil between services. I'll stick with the oil that provides the best health check.

 

JohnD.

We don't need a chemist for this one.

I would not recommend mixing the oils as they are formulated differently and you are likely to mess up the additive pack.

As Scooby suggests, buy the grade you want, be it 10w-50, 5w-50 or 15w-50 but consider the thermal stability of the oil before you buy if your car is re-mapped etc.

Cheers
Simon

 

Which oil has the best thermal stability ? I am looking at modding my Impreza to about 350 bhp......td05 turbo, FMIC etc. Its a daily driver that gets a couple of blasts a week what would you reccomend for that ?

 

Pro S 10w-50 is more thermally stable than RS 10w-60, all the PRO S and PRO R oils are extremely "shear stable", it's a question of which viscosity you wish to use 10w-50, 15w-50 or 5w-40.

Cheers
Simon

 

Would a 15w-50 not be a bit harsh for an engine with regular cold starts and cool oil temps during normal driving.

Dave

 

When I used to use Silkolene Pro S I found it sludged up very quickly and I had to change it more frequently (2000 miles). Once switching over to Motul or Castrol RS no more problems, also the Silkolene came out very thin as well as "dirty".
One other thing, with either Motul or Castrol RS idle oil pressure stays the same however hard I drive and over a good 7500 miles if I cared to take it that far (STi5 gets 3500 changes and STi9 gets 5000 changes). Even a track day doesn't diminish it. The Silkolene dropped oil pressure as the miles went on losing up to 0.9 bar over time.
Guess thats all about viscocity index. I'm not the only person to come across this as several experienced "ringers" also found the same was tru of the Silkolene.

As far as short and long runs, I do short trips on a daily basis (at least two of 5 miles) coupled with varied and random long trips during which the car get a mix of all conditions, on A/B roads it does get enthusiastic use. I have experienced no problems or issues with the thicker oils, no cold start problems, no noisy engine or clatter valve gear etc etc.

The only differences I have seen are improved oil pressure, cleaner oil and the ability to go further between changes.

There is nothing wrong with Silkolene in relative terms (to a 5-30 oil), its just that the other two brands I have tried perform better in my cars and under the conditions that I drive in. So since my own experience shwed good results it ain't broke and therefore doesn't need fixing as far as I'm concerned.

Oilman for your reference the STi5 has a very uprated spec and produces circa 500 bhp/400ft lbs torque and the Sti9 is mildly uprated producing 370 bhp/374 ft lbs torque, the STi5 runs 1.8 bar boost, the Sti9 peak and midrange 1.5 taper 1.32, both get used under the regime described above, also bear in mind the STi9 has VVT and I have observed no differences in cam control using the heavier oils either. Maybe a "too thin" oil would cause problems though.

Since you sell all I am not sure I understand why you are so hell bent on pushing Silkolene as its definately not as good in our engines.

Apologies to all for going on about this, but this is definately a case of "good advice" not fitting the application I'm afraid however many tech memos are used to expound the theory.

cheers

bob

 

Yes it would so 10w-50 or 5w-40 would be my choice.

Cheers
Simon

 

Well, in 10 years of selling Silkolene and other oils, it's the first time I've heard of this - Anyone else out there on this forum found this with Silkolene?
Which grade of PRO S were you using and how long ago?

Bob as an engineer, you will understand the effects of higher viscosity oils. Of course you will get high oil pressure but you're only seeing the resistance here not the flow.
Believe me and I know you don't, sae 60 oils are bad news when it comes to flow particularly in cold weather.

FYI the PRO S and PRO R products are ok for 7-9000 mile changes!

5w-30? Not sure what you mean here?
I seem to recall the recommendation was 10w-50 or 5w-40.

Bob, I am fully aware of the above, it still does not change what I am saying for two reasons:

1) I still can't see anywhere in the database that Subaru recommend 10w-60 however I can see 5w-40, 10w-40, 10w-50 and 15w-50 depending on the climate and I've looked as far back as 1993. In fact it does seem that the recommended oils have got thinner over the years not thicker.

2)Heavily modified engines, especially turbocharged ones need heat resistant PAO or PAO/ESTER shear stable synthetics, this is more important than the viscosity rating itself. I can assure you that after 2000 miles the "hydrocracked" Castrol 10w-60 will be thinner than the Ester/PAO PRO S 10w-50.

You're correct, I sell Castrol 10w-60, Mobil 1 15w-50 and a very large range of viscosities and approvals to fit vehicles from veteran to the latest spec Audi's but here is the important part...................

I never recommend oils unless I am confident that the Manufacturer does so, I'm in the business of selling and have no problem selling Castrol 10w-60 to anyone here but.............I cannot recommend it, as I see it from the data I have access to that would be unprofessional. Sorry simple as that!

Apology accepted, forums are about debates and differences of opinions at the end of the day people must take all the information presented (and it's better that way as information is the key) and decide for themselves.

Cheers
Simon

 

I got a question...
These cold start improvements of "thin" oils, if you have a positive displacement oil pump, which pumps the same volume of oil with each rotation (controled by crank speed) how can thinner viscosity oils 'travel' around the engine faster?
Surely the main differences they make is they can drain back into the sump quicker and reduce viscous drag therefore improving cold start fuel economy and emmisions.... (probably so manufactuers can meet/claim lower emissions and improve fuel economy for the us market to pay less tax etc?)

 

There is one large American oil manufacturer who is very rarely mentioned on here who produces a full syn. 5w/50 available here - Valvoline. I have used this in the past with no apparent problems.
The earlier comment about some American oils being less than ideal begs me to ask for comment on this product from those in the know, as in grade terms it seems just what we are looking for!
I have some technical blurb on Valvoline oils somewhere, sent to me by them on request. I shall search for it and quote spec. figures if anyones interested in comparing?
JohnD

 

Oilman,

Previously, you stated that Silkolene oils are based on Polyolester. After doing a bit of research, it looks like this is not true. As far as I can see Silkolen is based on a small amount of Di-ester thickened with some other even less stable stuff.

As you might know, Polyolester base oil is made as multigrade, so no viscosity improvers are needed. These viscosity improvers fall apart when subjected to heat and pressure. So Bob is quite right in his observations about Silkolene. The viscosity will change very quickly when subjected to the temperature of the turbo and the relative high bearing pressure of a Subaru engine. (I haven't even started on the subject of burnt oil deposits!)

Silkolene will work ok when changed very regularly. A polyolester based oil will not need these very frequent changes because the viscosity does not change over time.

I think it is time for you to stop pushing Silkolene to the people on this board. It is a fact that Polyolester based oils are the best lubricants for a Subaru. Unfortunately, polyolester base oil will not leave enough profit for most oil companies so lower quality substitutes are used.

As far as I know, the only normally available polyolester based oils are Motul 300v and Red Line.

So let's stop the BS and tell the truth.

regards,

Job

If I have offended anyone in this post, I have done so unintentionally.

 

I think I have a lab report somewhere on Valvoline 5w-50 but would need to dig it out. I have seen a MOBIL 5w-50 marketed in Continental Europe which has almost identical tech data to the Fuchs Titan Supersyn SL 5w-50.

If I can find the info I'll post here for all.

Cheers
Simon

 

Job,

Here's your reply. I don't want this thread to turn into a "slanging match" as it just detracts from the debates and interesting information posted here but I found the tone of your post aggressive and unecessary.

If you don't believe me then call this helpline number and find out for yourself as what I'm saying is clearly falling on deaf ears. If you want the data, ask them for it, I'm not employed by them and I'm sure they'd be happy to answer your questions themselves. 08701 200 400.

29.07.2004

Quote:

Simon,

This is the’ polyol ester’ magic word effect again! These things are just another type of ester. They are no different in function from equivalent di-esters or 2-ethyl hexane dimer types. The VI s of all esters are not sufficient to make a wide range multigrade (eg 10W/50) without VI improver. Good VI improvers do not shear down (I refuse to use this silly emotive ‘fall apart’ term) when subjected to heat and pressure. Motul 300V contains VI improver; the Red Line multigrades contain VI improver. If anyone claims that these conventional oils do not, BS is definitely present! JR


PS The best lubricants for minimising carbon deposits (‘burnt oil’) in turbocharger bearings are PAO/ester synthetics with the right high-temperature antioxidants and detergents. The Pro-S grades have performed very well in this respect for many years. JR

Cheers
Simon

 

I am sorry if my post sounded aggresive, did not mean to be.

As far as I am aware, the esters we are talking about are quite different. Polyolester is multigrade by nature. Very small amounts of VI improvers might be used but compared to other oils it is minimal.

Under proper load/temperature tests (not the silly ball bearing test) on a rheometer these oils perform hugely better with minimal stability or viscosity degradation. This seems to be underlined by some people's experience with their cars.

I will look up the typical molecular build up (going back to my university years now)of various esters to make sure that I am not just spouting rubbish.
I will also contact on old friend who works with Shell (I think they only use polyolester for their bespoke racing oils) to get his opinion just so that I can be sure that I am using the best available.

I am sorry that I upset you.

regards,

Job

Oh, by the way, I take it that Silkolene is di-ester based and not polyolester?
Your quote in a different post ('Regarding your question on esters, I know for a fact that Silkolene use polyol grades. They cost more but are better than diesters') might be wrong?

 

Oilman
The lab report on Valvoline 5/50 and your interpretation of it would be appreciated as I need to book the STi in for its year service and intend to supply my own oil, if I don't they'll pour Magnatec into it!
Other than my supply of RS10/60, locally I can get the Valvoline 5/50 and Millers XFS 5/40 synthetics as well as the Millers "competition" ( CFS) grades - how would the CFS oils fare for everyday use or is their additive pack not ideal? Lots of questions here but I'm enjoying this thread despite now being unsure of what to go for!!
JohnD

 

Somebody sent me this link which looks quite interesting as far as ester comparisons

http://www.petronomics.com/syn_what.htm

 

Quote:

Simon,

This is the’ polyol ester’ magic word effect again! These things are just another type of ester. They are no different in function from equivalent di-esters or 2-ethyl hexane dimer types. The VI s of all esters are not sufficient to make a wide range multigrade (eg 10W/50) without VI improver. Good VI improvers do not shear down (I refuse to use this silly emotive ‘fall apart’ term) when subjected to heat and pressure. Motul 300V contains VI improver; the Red Line multigrades contain VI improver. If anyone claims that these conventional oils do not, BS is definitely present! JR


Point of information:
Esters are the product of combining organic acids with alcohols.
Di-esters are made from di-acids with mono alcohols.
Polyol Esters are produced from mono acids and polyhydric alcohols.

They certainly are 'another type' of ester, but polyol esters have more compact shapes than the diester molecules, providing greater thermal and mechanical stability than the typically long molecules of the di-esters. Neopentyl esters, used as base stocks by Red Line, are particularly stable because their central 5 carbon atoms have no hydrogen atom attached. The neopentyl esters also give naturally a lower viscosity change with temperature than, for instance, di-esters, requiring minimal use of viscosity modifiers to meet conventional multi-grade parameters.

Gavin