Is BC truly a Group IV?

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May 6, 2004
Brooklyn, NY
I know that German Castrol is but how does Belgian Castrol 5W-40 compare. It is quite pricey compared to the Synpower 5W-40 I'm using (which is a Group III). I'm thinking of trying it though - any thoughts?
I's probably a group III...maybe a group III/IV mix.

Smells just like the other Syntec lineup (except for the GC).
The flash point of the BC is only 405F , thats not typical of most group III only's I've seen .

The MSDS does show it could contain one of two or both esters but again who knows for sure but many ester oils do have a lower FP . Just guessing around a bit

I bet Castrol knows

cP -25c 3300max
High Shear Vi CEC L-36-A-90 4.5
PP -33 max
Vi Index 175

It does have the sweet smell but w/o that distinct detergent smell like the rest of the Syntecs .
A number of sources point at this being a group III oil.

I have a '03 GTI VR6. I was planning on using this oil, but I'm now leaning more toward the M1 0w40, which appears to be a true Group IV synthetic, and I can get cheaper to boot.
Most likely this is Castrol TXT Softec 5W-40 which is III/IV mix. Does not matter, seems Castrol does not have 100 % group IV oil in 5W-40 weight at all. We heard many times that BMW oil is made solely by Castrol (though may be not only), but nevertheless, BMW label defines its 5W-40 oil as HC and PAO. Or it means that any 5W-40 oil supplied to BMW including possibly that of Castrol, is III/IV mix.
It works well is all I can say. Very good consumption and compression. Waiting to hear from my friend whom I gave a case to for his R32.
Junkie, there is also a version of TXT Softec that's 5w-40. Not sure why, but Castrol recommends it for diesel engines. It's API SJ/CF, ACEA A3/B3, and meets VW 500.00/505.00/505.01 specs.

Other than that, the only other Castrol 5w-40 oil I know is GTX Magnatec, which is group III, AFAIK.

Originally posted by Quattro Pete:
Other than that, the only other Castrol 5w-40 oil I know is GTX Magnatec, which is group III, AFAIK.

All Magnatec oils have esters in them, too.
And if that group III is Shells Slack Wax it ain't no slacker . Pardin the pun

I'd like to see this oil used in an engine that needs this formula . I would think it will do very well and is still yet priced less than most of it's competitiors from what I've seen .
All I know is it smells a lot more like the other Syntec lines and nothing like BMW's 5-30 which has more of a HDEO/Diesel oil smell to it (like Havoline synth. or Valvoline synpower).
I would have tried this oil in my VW 2.8, but at $6.85 at the dealer I decided to pass. But even if it does become available at a reasonable price, I doubt it would surpass M-1 T&SUV. Wasn't this oil loaded up with Magnesium?
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