My 7th UOA from Blacktone.
Car: 07 Subaru Legacy 2.5GT Spec B, 6 sp. manual
Miles on oil: 3,777
Total miles on car: 37,973
Air Filter: OEM
Oil Filter: OEM
This was my first run with Shell Rotella T 5w-40.
All previous runs were either Castrol GTX 5w-30 or GC 0w-30.
Wow, I think this is the second RTS uoa in a subie turbo that I've seen recently in which it sheared to a 30 grade. Other than that, it looks good!
Are you sticking with the severe service OCI for turbos? IIRC, it's not required until MY2008.
GTX has sodium, but it's odd that it actually increased over the last uoa. I see that you used GC only once.
I was a little concerned about the shearing to 30 grade, but that is better then my 5w-30 which used to shear to 20 grade.
I am going to stick with OCI ~ 4K, per the service service schedule.
I thought the Sodium was odd too, was hoping to get some insight on that here.
GTX is a great oil, but above and beyond that I am very impressed it did this well in this engine. Are you tuned at all? You also show less signs of fuel dilution than most of these engines; what type of driving do you do?
A solid report by RTS, but consistent with your overall runs as well, so not really showing anything special. The only nice thing is that it gave you a nice solid viscosity (comparatively). I don't remember the last time I saw RTS shear much, let alone in under 4000 miles.
This engine isn't a VW 2.0t or Audi RS4 V8, but it is hard on oils.
Something isn't right.
First off, your engine looks to be a great wearing engine. Doesn't matter whether GTX, GC, or RTS.
But that's where something doesn't seem right. I've seen a lot of UOA's of RTS, and haven't seen ANY with that low of Ca, Zn, and P numbers. You sure this was 5W-40 RTS?
I'm totally sure this was RTS 5w-40, the newer CJ4/SM one, I still have the bottle.
The only thing that I can think of: when I filled the oil filter up with oil before installing it, I filled it with Castrol Syntec 5w-20, left over from my girlfriend's Honda.
It would have been about an eighth of a quart of Syntec 5w-20.
Would an eighth of a quart of 5w20 change the Ca, Zn and P that much?
Nope. It would probably be unnoticeable. Blackstone must have gotten something wrong. I just wanted to make sure you are the one that changed the oil because you would know what you poured in. But, even you saw the 3 examples. Those are all fairly recent UOA's, too. Your sample looks nothing like the add pack in those three, and many others. It doesn't even look like an HDEO. It still produced great wear results, though.
Unless someone shows that VERY recently RTS has changed formulations to something with 1100 Ca, and 1000/900 Z/P.. I think this is a lab error. This may not even be your car's wear metals. I think I've seen this twice in the last week or two where someone got the wrong sample back.
I'm not calling disbelief, but a UOA link would be nice. Because one of those UOA's I posted, the guy said he used the SM/CJ4 and it was 2800ppm+ of Calcium. I know that it doesn't matter, BUT I just am curious to get to the bottom of this.
There was another one that showed about 1200ppm calcium, but I wasn't able to find it.
I'm wondering if there have been some bad batches of RTS.
Don't tell Ashland! Or we'll have a new Valvoline commercial