Tech data for Syntec 5W-40 and BMW Synthetic 5W-30

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Jan 14, 2003
Las Vegas, NV
I finally received the tech data for Castrol Syntec 5W-40. BMW High Performance Synthetic Oil is really the Castrol TXT Softec Plus 5W-30 with the specs listed below in German.


Castrol Syntec 5W-40

Specific Gravity, 60 F (15,5 C) (ASTM D1298) 0.85

Viscosity, cP @ 100 C (ASTM D5293) 12.80

Viscosity, cP @ -25 C (ASTM D5293) 3300 Max

High Shear Viscosity, cP @ 150 C 4.5

Pour Point, C (ASTM D97) -33 Max

Zinc, % Wt 0.10

Phosphorous, % Wt. 0.09

Flash Point COC, F (C) 405 (207)

fire Point COC, F 430 (221)

Sulphur, % Wt. 0.25

Viscosity Index 175

Total Base Number (TBN) 11

Below: Castrol TXT Softec Plus 5W-30 (AKA BMW High Performance Synthetic Oil 5W-30)

Sorry this is in German and I can't translate all of this:

Farbe 7,0- 9,0

Flammpunkt C 236 (ISO 2592)

Dichte Bei 15 C 847,1 (DIN 51757 T4)

Kin. Viskositat bei 40 C 68,1 (DIN 51562)

Kin. Viskositat bei 100 C 11,9 (DIN 51562)

CCS bei -25 3.1 DIN 51377

Total Base Number (TBN) 10 (ISO 3771)

Viskositatsindex 173 (ISO 2909)

I posted this because in the past there was some confusion about the specs of these two oils. When the two oils are compared the only thing that stands out is the low flash point and very high HT/HS viscosity of the 5W-40. The Syntec 5W-40 is sold at some VW, Audi, Mercedes and Volvo dealers for about $5.00 a quart in the USA. As far as I know only BMW dealers sell this particular 5W-30 in the USA and it is usually sold for about $4.00. This oil is not the same as the regular Syntec 5W-30. The 5W-40 is rated ACEA A3, B3 and B4 and the 5W-30 is rated ACEA A3 and B3. The HT/HS of the 5W-30 should be about 3.5 or 3.6 since it is rated A3/B3.

[ August 03, 2003, 02:41 AM: Message edited by: Sin City ]
Here are the specs for the 5W-30 in English:


Castrol TXT Softec Plus 5W-30 (AKA BMW High Performance Synthetic Oil 5W-30)

Color 7,0- 9,0

Flash point in degr C 236 (ISO 2592)

Density at 15 degr C 847,1 (DIN 51757 T4)

Kinematic viscosity at 40 degr C 68,1 (DIN 51562)

Kinematic viscosity at 100 degr C 11,9 (DIN 51562)

Cold Cranking Simulator at -25 degr C 3.1 DIN 51377

Total Base Number (TBN) 10 (ISO 3771)

Viscosity index 173 (ISO 2909)

I'm more interested in the 5W-40. Is the relative low flash point of 405 degr F (207 degr C) cause for any concern?

[ August 03, 2003, 03:12 AM: Message edited by: moribundman ]
Moribundman, thanks for the translation. I think the flash point of 405 F while not great is OK. I believe it was TooSlick that said this oil is known to perform quit well in the VW TDI 1.9L Diesels. The TBN of 11 is good and the HT/HS viscosity of 4.5 should be great for any older cars or any vehicle that simply requires a high viscosity oil.
That HTHS of 4.5 is amazing! But it makes me curious, how is it that an oil like this can have a 4.5 HTHS when it's 12.8 cst at 100c, but then other oils of even higher viscosities like M1 0w40, have much less? Does the quality of the base oil affect the HTHS or is it something else?

Originally posted by Sin City:
I finally received the tech data for Castrol Syntec 5W-40. BMW High Performance Synthetic Oil is really the Castrol TXT Softec Plus 5W-30 ...

I posted my theory back in May that BMW's 5w30 was actually TXT Softec. Thanks for confirming it.
According to both the Swedish and German Castrol websites TXT Softec is vollsynthetisch, so either Group IV or Group V. On the German website it is clearly distinguished from the hydrocracked oils.
If so, then the BMW oil is an OTC, full-syn alternative that has been available already. Why isn't there more known about this? Why aren't even the geeks on this board talking it up?

I would guess since it is not commonly available, and only BMW owners would routinely run across it, it is not well known. Even if the guys do know about it, maybe they don't want to depend on a BMW dealer for their oil and have such a restricted or potentially high-markup supply source. I have to tell you, now that I know about it, I'm interested...but then I'm an oilaholic so my perspective is skewed. (Actually, what I am REALLY interested in is Castrol Fomula R or RS.)

[ August 03, 2003, 06:54 PM: Message edited by: pscholte ]

Originally posted by YZF150:
If so, then the BMW oil is an OTC, full-syn alternative that has been available already. Why isn't there more known about this? Why aren't even the geeks on this board talking it up?

It has been talked about, but up until now most everyone has dismissed it as just another Castrol made "pretend" synthetic. Up until now, the German Syntec 0w30 is the only Castrol that has broken out of the Group III shadow of Castrol USA.

The 5w40 has suffered the same fate, even though it says on the bottles "Made in Belgium," and is, in all likelihood, a Group IV based oil.
Is BMW 5W-30 HP Synth a.k.a. Castrol TXT Softec Plus 5W-30 really a Group IV or V?

It's $3.80/quart at the BMW dealership, so based on that, I'm guessing it's a Group III. Would BMW dealerships sell a *real* synthetic at that price? It just seems too good to be true: that's Walmart's price/quart for M1 5W-30 when you buy the 5 quart jug.

According to a website I found, the pour point of 5W-30 TXT Softec Plus is -42C (-43.5F), which doesn't seem all that special: Chevron Supreme 5W-30 dino has a pour point of -46F and Valvoline dino has a pour point of -40F.

You make good points...since we don't have additional data all I can tell you is what I found digging around on the Castrol websites around Europe. I went back and "checked my work." On the Castol Deutschland website if you do a search for Castrol Softec TXT you get a hit summary that when you plug it into the translator indicates it is a full synthetic. When you get to the page itself, the wording, in my mind, leaves room for doubt. So bottom line: it's tough to tell for sure. I'm thinking this shouldn't be that hard.
I searched through a number of Russian and who knows what other language sites. I found this to compare it to the SLX 0W-30.

Castrol TXT Softec Plus SAE 5W-30
VW 502.00/505.00 (1/97)
BMW Longlife -98
MB 229.3

Castrol Formula SLX SAE 0W-30
SAE 0W-30
VW 502.00/505.00(1/97)
VW 503.01 (9/99)
BMW Longlife 01
MB 229.3
One more spec for Castrol TXT Softec Plus 5W-30 that I'm sure is of interest for many here is HTHS @150C of 3.5. In comparison HTHS for SLX 0W-30 is 3.58.

Softec TXT Plus 5W-30 is a factory fill only for non-M BMWs sold in North America, Europe gets SLX 0W-30 as factory fill. It's also interesting that Valvetronic NG type (I believe it stands for New Generation) engines are filled with what Castrol calls SLX LL01 FE, oil that is slightly different than regular SLX. I can dig up some specs if anyone's interested.

I get BMW Synthetic (TXT Softec) at my local dealer for $3.80 list and additional 20% discount for being BMW Car Club of America member. It is the best bargain you can find on a fully synthetic oil and it performs very well in my car, although I change it every 5K miles and oil capacity of 6 cylinder engine is almost 7 quarts and it makes a difference. As evidenced by some UOA this oil can go 15K miles in BMW engines without any problems.

Why is this oil that cheap if it is Group IV/V? I think its price is right when you consider that there are no marketing costs and it's distributed only through the dealers.
There are still several of us on this board that noticed ugly brown deposits on the valve cover caused by using the BMW oil in our engines. I removed my valve cover and cleaned all of the "mud" from the cover and have not used any of the BMW oil since.

Someone had posted a 15,000 mile OCI using the BMW oil in a 3 liter (I believe) engine on this forum and I don't recall it looking impressive at all.
I missed something or something wrong with 4.5 HT/HS for Castrol 5W-40.

European Castrol TXT Softec Plus 5W-40 was the only oil Burmah Oil manufactured in 5W-40 grade for gazoline engines. 2 or 3 years ago it was substituted by 5W-30, but in some countries they are still marketing it.

5W-40 was always a synthetic technology oil that means not fully synthetic from Mobil initial (and
not actual) approach. As I know (Castrol 10W-60 was my first love) 5W-40 was and is still PAO + HC oil like, however, nearly all European 5W-40 and 5W-30 synthetics now.

Castrol TXT Softec 5W-30 has better stock, especially once it was certified by API SL that is quite unusual in out time. Good, but nothing exceptional. Castrol TXT and SLX also exsist in GM, BMW (2 types) and Ford formulas. You can look Typical Properties and Specs at: -> Produkty -> Oleje Silnikowe Do Samochodow Osobowych

Think Latin letters in Polish will be easier for reading then Cyrilic letters in Russian.

BMW oil. In the past it was called "BMW Power Oil". Now it is called "BMW High Performance Oil" and, as I could see, sold in 4 different grades:
synthetic 0W-40, 5W-30, 5W-40
semi-synthetic 10W-40.
By the way, 5W-40 label bears "Synthetic (PAO + HC)
Castrol is the main supplier last 2-3 years, but think not a single one.

The Slavic love affair with motor oil is a beautiful thing. It makes an old, no let's say mature, oilaholic very proud.
Interesting that you mentioned brown deposits, I've never heard about accumulation of deposits from using that oil but several fellow BMW owners mentioned reddish brown deposits on the filler cap that were traced to some metal part rusting and were not limited to BMW branded oil.

I've seen very positive UOA, nothing spectacular but oil certainly lasted 15K miles. One of the posts was on this board from 528i I believe.

I wouldn't recommend using this oil or any oil for that matter for 15K miles in a small, high revving 4 cyl engine with an oil capacity of 4 quarts but it is a nice alternative to 5W-30 or 10W-30 M1.
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