Sludge?

[ARB1977]

Can you see any of the top end through the oil fill cap? If it's clean they pulled a fast one.

 

[SubieRubyRoo]

Nope, because of the shape of the oil fill tube there is no way to see into the head. However, as a point of reference, I had the valvecover gaskets and donut thingies replaced on my 01 Forester at 165k because of oil in the spark plug holes. I stood next to the tech and looked at the heads, and there was no sludge to be seen anywhere, even with 90% of the car's life unknown to me at that point (I'm sure it was conventional all its life). Considering this was on an EJ25 which is known to be tougher on oils than the new FA/FB engines, and the OP was using good oil and reasonable OCIs, there is no way he's got sludge.

Castle Subaru are all a bunch of crooks from my personal experience with them. Bob Rohrman in Fort Wayne or Lafayette are alternate dealerships if you're in need and don't want to give the service department at Merrillville a try. My mom bought her Forester there last year and is nothing but tickled pink with their service dept., other than the cost of dealer parts. Your call, good luck!

 

[GZRider]

I'm also super skeptical about your Subi slugging up with a 7,500 OCI on Mobil1, I had an 08 3.0 Outback and an 10 Imprezza and while I have many many many things to say about Subaru's engineering, they weren't hard on oil. Even Vanilla Mobil1 5w30 will reliably stand up to IS/GS 2GR or the VQ37 for a 7,500 OCI without issue *outside of track duty* That little Subi four banger just doesn't make that much heat or abuse oil the way more some VVEL systems and Turbo's do, some of which have factory 8-10k mile OCI's with that oil.