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synthetic oil vs semi-synthetic

143K views 331 replies 71 participants last post by  Spyder 
#1 · (Edited)
Hi,

I am a bit concerned, I went to a independant bmw specialist and he did my oil change with semi-syntetic motul 15w50 oil. I always used castrol tws 10w60 in my engine.

He told me the tws I was using, was useless in my engine because it was designed for the latests bmw m power engines. He told me the motul oil was better suited for my car and that i was paying to much for the castrol tws. My concern is the change from synthetic to semi synthetic... Am I doing something wrong?
 
#2 ·
A semi synthetic has a small percentage of Group 3 base oil in it - 10-20% IIRC.

Full synthetics comprise 100% Group 3 or Group 4 base oil. TWS is formulated with Group 4 (PAO).

TWS cannot even be compared to a Motul Semi Synthetic, the former is way way better in its lubrication properties. By way of example, normal group 1 base oil costs $1300per Ton. A group 3 costs about $2300per ton and a group 4 about $ 3500per ton. If oil companies could get the same lubrication properties with group 1s, believe me we would .

You dealer obviously has the Motul in stock - bulk or in 210L drums. He naturally wants to sell it to you.
 
#4 ·
Look if it were me, I'd replace it as soon as convenient to do so.

Providing you are not driving your car hard, running up to the red line, or tracking your car, its probably okay. That said, that not how one drives a //M car is it?
 
#5 ·
Fantastic response .......For a minute , I thought this was going to turn into another one of those inane oil threads .

It's suprising how many mechanics will base their advice on what suits their own purposes ........ thank god he didn't have a barrel of Planet oil in house !
 
#10 ·
IIRC it was one of the BMW Motorsport division guys in Germany that recommended the use of Castrol Edge / TWS 10W60 specifically for the S38 engine .

Do you mind me asking who suggested otherwise to you ?

We need to consider that oil technology has moved on vastly from 1995 when the last of these S38 engines were put into E34 M5s and the owner's manuals produced .
 
#12 ·
I can't see any reason why TWS 10-60 would cause accelerated wear in S38 engines. I'm sticking to it, especially after the guy from M-division recommended it for extra protection of the bearings ,which has been a weak point of some S engines. I doubt there are many better oils out there for S38 engine.
 
#14 · (Edited)
Forget the brand names. Its not the issue.
Synthetic or semi-synthetic is not the issue.
Castrol make great oils. The viscosity is the problem.
Please refer to your vehicles handbook.

Back in the mid 1990's Ford motor companies franchised dealers started selling
Mobil 1 in 0w/40 instead of its previous iteration 15w/50 = recommended for
Cosworth FI engines.
Ford & its supply chain said its "Approved"
This new viscosity of oil was not developed or tested for the Cosworth FI engine.

Many engine issues were reported from excessive oil consumption
through to worn cylinder heads, bores & blown engines ( pre-ignition caused
many destroyed engines that still ran a closed loop crank recirculation breather system )
The RSOC took it to FOMOCO, as did some of the racing & rally teams that were partners to Ford.
The oil you know currently as mobil 1 rally was the oil hastily restocked.
Its viscosity grade..15w/50

That very same Mobil 0w/40 oil viscosity forced a change in ring pack & piston to bore
tolerances on the last 3 yrs production of Aston Martins V8 "Vcar" production. :1zhelp:

Personally...
Please keep using the incorrect viscosity of oil for these engines.:applause:
The more of you that use 10w/60, the better it will be for BMW who
supply powertrain parts for these vehicles in increasingly limited batch runs &
those who can fit them..properly.

Why is it that 10w or 15w /40 oil has served countless hard driven high mileage S38 engines with no obvious damage ?
Yet those running 10w/60 for the last 4 yrs & much less have excessive camshaft pitting & obvious
considerable carbon depsosits everywhere that is visible ?
It must be coincidence !:3:

Current high performance engines, developed in parallel with the manufacturers of those lubricants give us
the extended service intervals.
That is also a function of better manufacturing process & surface treatment of the moving parts.
Oil technology has moved on.
Mass production engines & emissions technology has moved on.
The S38 is right back there isn the 1980's.

Please look out for posts by a new member who is currently registering.
His ID is "Oilman" ( see Dan Kellys link to Ivans post).
His past technical contributions to other messageboards have been first class.

Cheers
Farrell
 
#15 ·
Forget the brand names. Its not the issue.
Synthetic or semi-synthetic is not the issue.
Castrol make great oils. The viscosity is the problem.
Please refer to your vehicles handbook.


Personally...
Please keep using the incorrect viscosity of oil for these engines.:applause:
The more of you that use 10w/60, the better it will be for BMW who
supply powertrain parts for these vehicles in increasingly limited batch runs &
those who can fit them..properly.

Why is it that 10w or 15w /40 oil has served countless hard driven high mileage S38 engines with no obvious damage ?
Yet those running 10w/60 for the last 4 yrs & much less have excessive camshaft pitting & obvious
considerable carbon depsosits everywhere that is visible ?
It must be coincidence !:3:

Current high performance engines, developed in parallel with the manufacturers of those lubricants give us
the extended service intervals.
That is also a function of better manufacturing process & surface treatment of the moving parts.
Oil technology has moved on.
Mass production engines & emissions technology has moved on.
The S38 is right back there isn the 1980's.

Please look out for posts by a new member who is currently registering.
His ID is "Oilman" ( see Dan Kellys link to Ivans post).
His past technical contributions to other messageboards have been first class.

Cheers
Farrell
Darren ,

Whilst viscosity is obviously an issue , it is not the only issue .

Quote from the oilman : ' if you drive a high performance or modified car, and you intend to keep it for several years, and maybe do the odd “track day” or “1/4 mile”, then you need a genuine Ester/PAO (Poly Alpha Olefin) synthetic oil. <?XML:NAMESPACE PREFIX = O /><O:p></O:p>
<O:p> </O:p>
These oils cost more money to buy, because they cost a lot more money to make.<O:p></O:p>
<O:p> </O:p>
Very simply, you always get what you pay for, cheap oils contain cheap ingredients, what did you expect! '

This would suggest that viscosity is not the only problem !

May I ask , exactly which powertrain parts that you have personally seen fail as a result of running 10w60 ?

You mention the owner's handbook which suggests 15w40 or 15w50 and yet the oilman recommends 5w40 fully synthetic .......Why has he deviated from the handbook ?

Darren , I respect your knowledge and I also respect your experience .....however , I also remember you having no problem whatsoever with adding a bottle of my Castrol Edge 10w60 to your S38 on our visit to Bruntingthorpe and hope that whatever other oil was floating about in the sump was sufficient to lessen the negative impact that this addition may have caused !
 
#16 ·
So there's no problem with a fully synthetic 10w40 then :dunno: or do we need the oil companies to produce a 12.5w45 to suit everyone :hihi:

I just buy the cheapest 'good' synthetic I can find at the time - it just meant that this time it was 25L of Silkolene Pro-S (at £30/5L).

If I know I can 'get away' with using 'cheaper' 10w40 Magnatec, GLX, GTX, Chevron and the like (Chevron's about £25 for 25L at Costco, but don't know what spec it it) and can save 50-75% on regular oil bills then it means over 20,000 miles I'll save £130-£190 a year (assuming 3 interim oil changes @ 6 litres and top-ups @ 1L/1500 miles = 33 litres @ £3.50/litre).
 
#17 · (Edited)
.....so this has ultimately reverted to one of the dreaded oil threads.:1zhelp:

I guess since this is an issue very close to our hearts, and engines, a resolution will be very hard to come by. :7:

So what do we do ?

There is sooo much info. on which oil to use and which not to use that one can burst a blood vessel thinking of which way to go.

I initially used Castrol Magnatec 10w/40 but got a huge consignment of TWS Motorsport 10w/60. Changed the oil a couple of weeks ago and the engine seems to be running much smoother.

My thinking was based on the research I did on site here and the fact that we have high temps. all year round.

On some of our long trips while doing 240km/h for over 300km's we see temps. over 100F with extremely high humidity....:3:.

I sure as hell don't want to see premature cam wear on my engine given these operating conditions......but what is the correct way to go :dunno: ?
 
#18 · (Edited)
David
This is the full thread from which you are quoting :
http://bbs.scoobynet.com/general-technical-10/608314-oil-you-get-what-you-pay.html
Your grasp of oil technology is simply quoting what another
Engineer has quoted but this is more in context on forced induction engines in the main
where lubrication duties have vastly greater temp / pressure criteria than that
found on a large n/a engine with a very efficient engine oil cooler fitted as std.

Thats why I use Mobil one 15w/50 synthetic on my Skyline.
It's duty cycling means constant exposure to several hundred degrees Celcius within the
intermediate housing of the turbocharger.
In extremes, the Turbocharger can reach 1000 Deg C
All that with high pressure oil feed to the turbine shaft bearings, you need
the best chemical formulation when bulk oil temps exceed 140 Deg C
Its resistance to breaking down under these much more extreme conditions make
it worth paying for.
With the added security that its an oil that is proven to work in a forced induction vehicle using the
correct viscosity.

May I ask what the highest bulk oil temperature you have measured on any of the
E34 M5 's you have owned ?

I would suggest that whilst viscosity is not the only issue , in context of the application for S38
where oil bulk oil temp rarely, if ever exceeds 110C or around 230F, the engines do not need anything
remotely exotic.
The "Planet oils" I use are rated far beyond this temperature.

The S38 application :
The vehicle in B36 guise was a world vehicle in 1988.
In B38 circa 1991,it was a mainly European offering due to pass-by noise & emissions
In all cases, it was tested on Cold crank test, Autobahn signoff, Altitude soak @ Grossglockner &
as you have quoted, many thousands of Kms at the Nordschliefe.
All this with Mineral oils @ an average of 6k mile service intervals.
So then, whats changed please ?

Oilman has recommended 5w/40 for colder climates & winter use where more
efficient cold crank can utilise the thinner when cold oil.
He has just been approved as member & I am sure he will be happy to answer
specifics.

David
I have seen no actual failure of the valvetrain parts in this application...yet.
What I can say without doubt is the that all the cars I have seen
running 10w/60 have bad pitting of camshafts.
No exceptions.
These engines as exmained have as little as 90k miles on them.
From past experience, it has been documented that when pitting gets bad enough,]
the surface hardening of the cam no longer has
the integrity.
The compression, shear & turning forces concentrate on the damaged areas.
These areas being softer are more likely to fracture over time with
micro-cracking emanating from the damaged areas.
When a camshaft lobe disintegrates, its usually fatal for the engine.
No big mystery.
Same with crankshaft bearing shells in that once you are through the hardened land,
then,wear through the soft shell & potential brg shell being spun out by the crank, a likely conclusion.

The 10w/60 oil you lent me was drained the next day as you know.
Thankyou.

My own engine has no pitting or visible damage of any kind @ 180 plus k miles.
All run on 10w or 15w /40 "Planet oil" for the last 8 years.
A highly stressed ,fragile, about to go bang 3.8zzzzz
Wow, who would have thought it.
 
#21 ·
My own engine has no pitting or visible damage of any kind @ 180 plus k miles.
All run on 10w or 15w /40 "Planet oil" for the last 8 years.
A highly stressed ,fragile, about to go bang 3.8zzzzz
Wow, who would have thought it.
Farrel, your words above remind me of a discussion I had with a friend many years ago.

We were in the bush, middle of no where, the subject turned to 2 stroke oil. He was mocking the rest of us for using expensive synthetic TTS 2 stroke, wasting our money.

He only bought cheap 2 stroke, the stuff you get at fuel stations, product mostly used by mopeds and delivery bikes. He had recently taken his bike to the local Yamaha workshop and the mechanics had remarked how crisp and rattle free his motor ran.:cool2:

Yeah, we were idiots.yawnnnn

Well not one hour later he was a little red faced:grrrr:, his con rod protruding conspicuously through the front of his engine casings. Worse still when he had to beg the 'synthetic boys' for a tow home.

Not saying this is going to happen to you:cheers:. I would how ever caution your overconfidence.

We can argue which viscocity is best suited to each application. Bottom line remains that full synthetic oils are always going to provide better lubrication and protection than mineral based oils.
 
#19 ·
i was under the impression that infrequent use was a cause of the cam pitting? My m5 has a small amount of pitting (compared to pitcures i've seen posted here), as far as i can see thru the oil cap hole, and has used 20w50 Kendal GT1 or Castrol GTX 10w40 for most of its life (up to about 145k miles). I put TWS in, as that's what i had in my cabinet for my e39, when i last changed it.
Personally, i just want to use what is best for the engine, be it cheap or exotic, i wont discriminate!
 
#20 ·
Yes Mike
I believe intermittant use could be a factor.
However, the cars I have seen were users apart from one.
Again, I am not with the ownersouich
At the same time, my own car has seen intermittant use for the last 2 years.
I am not seeing the wear issues.
I am not an oil Engineer so I would prefer them to have a definative say.
I can only convey personal long term usage, past experience & what I am
finding now & log the findings @ mileage first seen.
 
#60 ·
Is Faz claiming to be an oil expert in this thread ?

The oilman is recommending an oil different to that recommended in the owner's handbook .

The wonderful thing about being a part of this forum is the vast amount of knowledge and experience that we can draw upon .

I personally have had no issues with Castrol Edge 10w60 .

I personally have had no issues with Silkolene Pro S 5w40 .

Both are high quality oils !

A man cannot be comfortable without his own approval !
 
#22 · (Edited)
I'm using a 5w50 Manhiem Synthetic. Engine runs very smooth, burns very little oil and I do not drive the car in the winter months.Am I putting my engine at risk?
 
#23 ·
I m kind of lost... Some of you guys say that I should stick with previous TWS and others say that I should avoid it because of the too high visquosity! The oil I'm using now is qualified as mineral(motul 4000 motion 15w50) but my tech told me it is in fact semi-synthetic. Am I being bullsh*ted by my tech... My worst fear is to cause harm to my engine!:confused:
 
#28 ·
Don`t worry pal. You are not doing any damage to the engine whatsoever. That oil you have mentioned fullfills the requirements for the engine and has good heat viscosity even for harder use. If you want you can change back to
Whatever oil you used before at the next oilchange.
No need to take extra measures.

:cheers:
Sakke
 
#24 ·
I've been using 15/50W synth for hard road use without car using much oil - I'll be sticking with that no matter what anyone says.

Fair play to oilman, some of his advice is magic, but some of it isn't - it's very generic. As ever, you pays your money you takes your chances - my ITR drank previous recommended opie oils and I won't be repeating that ... it's one thing on a new engine, quite another on one with loads of miles on it.

I'll be following his advice on my new car, for 5/40.
 
#25 ·
Mauritius Maria had been run on Castrol Edge 10w60 for almost a year prior to Farrell attended to the valve clearances and displayed absolutely no pitting to the cam lobes .

I am also talking from personal experience based on the ownership of more than one E34 M5 .

I have also seen an indicated oil temperature of over 240F on a trackday at RAF Woodbridge in Aug 2006 whilst driving my 3.8 avus .

As an engineer , I would expect your recommendations to be based on facts and a broad case study rather than hearsay .

I know for a fact that the oilman has not seen one failure of an S38 engine directly relating to the use of Castrol Edge 10w60 .
 
#44 ·
I know for a fact that the oilman has not seen one failure of an S38 engine directly relating to the use of Castrol Edge 10w60 .
True, I have not seen an engine go bang due to the use of 10w-60, but premature and excess wear is a different story.

Cheers

Guy.
 
#26 ·
P.S. The thread from which I am quoting can be found on the oilman's section of the BMW Car Club forum :

http://www.bmwcarclubforum.co.uk/forum/forum_posts.asp?TID=1136

He has been posting on there for quite some time .

p.p.s. When you lend someone something , you tend to receive it back ..... To GIVE is an entirely different concept !

Best Wishes ,
D
 
#29 ·
Boys, boys....
What with this harsh tone???? I thought you wo were pals....:confused:
Take it easy.

:cheers:
Sakke
PS: I have used the TWS for past 5 years ca 50000mls. Ambient temps from -30C to + 30C I have not received notions on pitting on my cams, nor have I seen it, It does not prove anything, it is just my car.:hihi:
 
#30 · (Edited)
This issue is an unsolvable one in my opinion.

But since I am a lay person when it comes to oil I'll tend to go with the Fazmeisters opinion on this issue.....and the simple reason is that anyone who could have steered me towards my car, which was in almost perfect condition after he worked on it too, must know something about these cars and must be doing something right !

I would much prefer to err on the side of the experts opinions than on mine.

I tend to leave intricate details to professionals.

In addition many arguments seem to have merits but this is just my opinion.

BTW...anyone want Castrol TWS 10w/60 ? I have over 25 1litre cans....if i can't sell I'll dump them in my Toyota Camry....after all its a Toyota, if the oil kills it who the hell cares !!!
 
#32 · (Edited)
Gents,

My S38 and M88 engines ran and still run fine on TWS for more then seven years. They did not fail so what is the fuss all about ?

It's the cam pitting that my S38 (not M88). But it is not that bad and some spots can only be seen by a trained eye. But it's there. Same like the cam lobes do look blueish. I have read a post in the E39S section in which the abolute viscosity values have been published of a 10W60 and 10W40 oil. This led me to believe that the oil operating temperature of an S38 engine for normal road and simple track use is not high enough to benefit from the advantages of a xW60 oil. Granted, the temperature household within an engine is much more complex then the simple gauge value that is measured on one point and doesn't mention the hotspots. I do believe that some parts in our S38 engines benefit from a xW60 oil, but there were the oil temperature is lower (higher up in the engine), the added benefits of a xW60 oil is not an advantage anymore, hence the wear I see on my cam-lobes.

Back in 1987/1988, BMW did not test a xW60 grade oil for our S38 engines. In that respect, I fully concur with Darren. Therefore, I will switch to a 10W40 grade oil with the next oil change of my E28S and E34S. However, these have to be synthetic and not semi-synthetic as that choice is no discussion.
 
#34 ·
Chaps, this innocent thread is becoming a bit twisted.

Lets all agree to disgree ?

When it comes to engines I'm by the book regarding specs.

When was the last time a car manufacturer rewrote oil filling specifications
several years after a car was homologated & tested ?
I've never heard of it and I worked for a manufacturer for 5 years.

Or to think about it another way......

Were you to have your S38 rebuilt by BMW, or a long engine be replaced
under warranty.....and you suffered a subsequent failure of that engine
(camshaft, main bearing, rings etc)

Do you think BMW would replace that engine or honour any warranty claim
if you were running oil outside the recommended spec ?
Be it higher or lower spec oil ?

I don't think so.

No ones mentioned "wintershall" in this entire thread and yet all our
vehicles were delivered with this sticker under the hood/bonnet.


Just another perspective chaps.

Regards,


Alan.
 
#35 ·
Chaps, this innocent thread is becoming a bit twisted.

Lets all agree to disgree ?

When it comes to engines I'm by the book regarding specs.

When was the last time a car manufacturer rewrote oil filling specifications
several years after a car was homologated & tested ?
I've never heard of it and I worked for a manufacturer for 5 years.

Or to think about it another way......

Were you to have your S38 rebuilt by BMW, or a long engine be replaced
under warranty.....and you suffered a subsequent failure of that engine
(camshaft, main bearing, rings etc)

Do you think BMW would replace that engine or honour any warranty claim
if you were running oil outside the recommended spec ?
Be it higher or lower spec oil ?

I don't think so.

No ones mentioned "wintershall" in this entire thread and yet all our
vehicles were delivered with this sticker under the hood/bonnet.


Just another perspective chaps.

Regards,


Alan.


Good post !

:cheers:
 
#40 ·
Hi David just to add my tuppenny worth. I am no mechanic nor a oil speciallist, however I was under the impression that you have been taking cars to the fazmeister for years. If this is the case are you saying that he has been putting the wrong oil in your cars. !!!! I also thought that you bought and sold cars but faz has been with you to check vehicles prior to purchase. If you trust faz to such a degree I fail to grasp why you would even question his authority on such a matter. I have not known faz as long as you have and I am under the impression given previously by yourself that there are very few if any with the knowledge that he has. Having read the oilmans thread I fail to see your reasoning unless I have miss understood something. Anyway I suppose a choice of oil is a personal thing if you have the knowledge and experiance. As my knowledge and experience with these cars is limited i will go with the knowledge and experience of the faz. From my personel experience and reading of the many threads he has posted or answered the guy is a genius and should be respected more.
Andy
 
#66 ·
Hi David just to add my tuppenny worth. I am no mechanic nor a oil speciallist, however I was under the impression that you have been taking cars to the fazmeister for years. If this is the case are you saying that he has been putting the wrong oil in your cars. !!!! I also thought that you bought and sold cars but faz has been with you to check vehicles prior to purchase. If you trust faz to such a degree I fail to grasp why you would even question his authority on such a matter. I have not known faz as long as you have and I am under the impression given previously by yourself that there are very few if any with the knowledge that he has. Having read the oilmans thread I fail to see your reasoning unless I have miss understood something. Anyway I suppose a choice of oil is a personal thing if you have the knowledge and experiance. As my knowledge and experience with these cars is limited i will go with the knowledge and experience of the faz. From my personel experience and reading of the many threads he has posted or answered the guy is a genius and should be respected more.
Andy
Hi Andy , I have , as you mention , always been highly respectful of Faz and his knowledge even saying as much in this very thread .

He has always had my whole hearted support both before and after deciding to become an independent BMW specialist and I continue to wish him well in that quest .

In fact , I was one of his first paid jobs upon him declaring himself as such after requesting that he check the valve clearances on Mauritius Maria who I knew to be running like a steam train .......as expected there was no adjustment required .

However , Faz has never changed the oil in any of the cars that I have owned as I use my own mechanic .

Of all the cars that I have ever owned or viewed , Faz only ever accompanied me on one occassion .

The levels of respect that Faz and I now have for each other are determined by the personal experiences that we have shared and cannot be decided by 3rd parties whose experiences may be completely different .

I respect my mother but would not hesitate to question her should I feel that something she was saying may not be 100% gospel !

I trust that this clears up any misconceptions that you have had and assures you that I am only hoping to arrive at a factually correct conclusion to the issues raised in this thread !

D
 
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