GC Question

[walker33]

I'm coming up on my oil change time again and was planning on hitting my GC stash. I felt GC was a good choice for my car (2010 WRX) being it's Subaru with a turbo.

Now I'm wondering since reading over the the threads about Noack numbers, would I be better off going to a 5w-30 synthetic with a low Noack number for better wear protection or stick with the GC for shearing protection?

I don't beat the car, but I do enjoy wringing it out. I do about 350-400 miles a week, all highway but occasionally get stuck sitting in stop + go traffic for extended times.

Could be, it's a waste of brain cells, since I have to stick with the factory OCI of 3750 miles anyway.

Thanks.

 

[dparm]

Neither of those oils is going to have any issue running to 3750 miles. If you already have a stash of GC, just use that.

 

[SLCraig]

I would for sure rock the GC.
I would use that oil in both my cars if it were available in jugs and not ALWAYS full price here. Which is about $10/quart.

 

[gathermewool]

Since you're sticking with the severe service interval (I thumb my nose at Subaru, personally haha) I'd only worry about switching to a lower volatility oil if you were having consumption issues.

 

[d00df00d]

Originally Posted By: walker33
Now I'm wondering since reading over the the threads about Noack numbers, would I be better off going to a 5w-30 synthetic with a low Noack number for better wear protection or stick with the GC for shearing protection?

NOACK is about volatility, not protection.

Where did you find NOACK numbers for GC?

Either way, GC should do just fine for your engine. The big question is, doesn't your car require an API SM oil? If you're willing to stick with a 3750 mile OCI for warranty reasons, I think you should stick with the recommended oil specs as well.

 

[walker33]

"Where did you find NOACK numbers for GC?"

I went by the list in the "Is Castrol Edge 10w-30 improved over GC" thread. If the Castrol Syntec 0-30 is GC, it shows 11.28% NOACK.

Subaru also lists SL under severe use, I was under the impression that most driving is realistically considered severe and by using a thicker 30w would help protect the turbo + engine. Many people in the Subaru forums use a heavier weight oil.

 

[d00df00d]

Originally Posted By: walker33
I went by the list in the "Is Castrol Edge 10w-30 improved over GC" thread. If the Castrol Syntec 0-30 is GC, it shows 11.28% NOACK.

From a couple of quick searches, that number seems to be at least as old as 2006, and I know GC has gone through at least one reformulation since then -- not to mention the fact that I couldn't find a source for that number. I wouldn't use it as a factor in a decision.


Originally Posted By: walker33
Subaru also lists SL under severe use

Alright then. No worries about GC in that case.

 

[yaris0128]

No sense in buying more oil if you already have a good GC stash. Keep using it until you need to restock. I didnt know that Surbaru had such a short oci, seems crazy in these modern times.

 

[A_Harman]

Pardon stupid questions from a newbie, but what is GC short for? I'm thinking Castrol GTX.

Is there a page on this site that decodes the abbreviations that are commonly used?

 

[lexus114]

Originally Posted By: A_Harman
Pardon stupid questions from a newbie, but what is GC short for? I'm thinking Castrol GTX.

Is there a page on this site that decodes the abbreviations that are commonly used?


Good guess,but not quite

. It stands for German Castrol Syntec 0W-30 due to being made in Germany.

 

[d00df00d]

GC = German Castrol. It refers to Castrol Syntec 0w-30, which is made in Germany unlike the rest of the Syntec line.

 

[HK_Ace]

and it is some yummy stuff!

 

[walker33]

Thanks everyone. Looks like I'll be hitting my stash of GC!