Rusty-colored buildup in engine

So long story short, my car blew the head gaskets... again. Bought it with them done near 100k, blew at 135k, so obviously the previous job was done by a POS mechanic.
The symptoms were, coolant was disappearing, but there was no oil in it. My friend/coworker said it was a head gasket and that he could test for exhaust gasses in the coolant... it was there.
This friend of mine has replaced 4 Subaru head gaskets and just did a WRX swap into his Forester, so I felt he's a guy I can trust to do the job.
We pulled the engine and removed the heads to find this sight...



So my questions (and his) are, what is it? Where did it come from? And what should be done about it?

I think it is just left over from the coolant and the oil/exhaust gases mixing. I saw some orangish stuff like that when I replaced my head gaskets. I don't know if it was as bad as yours since my engine is closed deck and you can't see around the sleeves like on yours.

I just flushed the passages out. I wouldn't worry too much about it but I'm not sure what the best thing for you to do would be.

Okay, that's good to know. We kind of figured that it'd be the exhaust gas that would cause it. There's not a lot of steel to be rusted in this aluminum block.

looks a lot like the same color the "coolant" was in a ford contour that i flushed and replaced a rad hose on last night. took forever to flush that color out, and im sure when we do the power flush it will be right back. ive had that color in the engine of an old chevy i rebuilt, but it was ran with straight water for years before i rebuilt it. i assumed it was rust from the water pump, metal springy hoses, heater core and whatnot that is attached to the system. if it were my motor id probably clean it out and make it purty before putting it back together.

That's definitely the goal. Question is, what's the best method?
Steam? Oven cleaner? A wicked toothbrushing?

i have not found a task yet that brake cleaner wont eat. soak the living hell out of it and then rise/pressure wash

Well when green coolant and oil mix it will look like a light tan color and that doesn't from the pic. What it probably is, is some miracle in a bottle head gasket repair. Just clean it out goo and you "should" be ok. Make sure you clean out your radiator, hoses and heater core really good. That crap will clog the hell out of those parts and cause you issues down the road.

I was told to clean the engine with the BLUE CAN of EASY OFF OVEN CLEANER. Results to follow.

Now if someone could tell me to find a parts list with numbers and a diagram, I need to find parts... Genuine Subaru ones... For an EJ25D...
That person would be my hero!

Head Gaskets
Exhaust Gaskets
Valve Cover Gaskets
Head Bolts
Lower Idler Pulley (possibly)

http://opposedforces.com/parts/legacy/us_b11/

Do I win?

You might be... but their page is down.

It was just working yesterday...I hope it didnt go down for good

It's back up and you are my hero! Found the parts list...
Can't find all the parts FOR SALE... but I have their numbers now

Thanks!

IME - that gunk comes from running plain tap water in the system...much of it is rust. PO could also have run Stop-Leak in it in a mis-guided effort to seal the HGs. That crap will cause that mess as well... but my first assessment would be tap water.

I wouldn't doubt that it's a little of both. Once I started going through coolant like mad, water was used. But the previous owner's history... not sure.

I've located all of the needed parts on subarugenuineparts.com (other than a timing belt). They beat all prices, even with shipping. So if you are like me, have a bad head gasket and need to redo a motor, I'd highly recommend them for your parts needs.

use either already mixed coolant or if you use full strength, mix it with DISTILLED water.
And remember to replace that radiator cap!! They do wear out.