I recently replaced old cap for a new cap. Old o-rings were shot. I stopped the coolant leak entirely this way. But now the coolant has drained from the reservoir and I see this on the cap.

Best/worst case scenario?

Options? Suggestions? Will do whatever is suggested. Want to fix this car up so it lasts.

How likely is it that the block is cracked?

 

Looks like normal bit of crap in coolant from 13 or 14 years of use. Drain the coolant and refill with fresh Dexcool 50/50 mix. You can buy it already mixed.
Do not use any flushing liquids or such .
You did a compression test and all cylinders were equal around 130 psi, so it’s not a cracked block of a head gasket. wipe the new cap off and reinstall it.
Burp the coolant.

 

He just said it's a new cap. I thinks that's oil emulsion and that's not the first time he's heard it.

 

Looks like you have oil getting into the cooling system.
BTW What does the res look like?

 

coolant is under 15 psi oil is under around 5 psi. How would a head gasket allow oil to coolant?
If this is the basket case SS I would look at the turbo or oil cooler.

 

The oil pressurizes immediately. The coolant doesn't pressurize until it heats up.

 

I've already put about 2 or 3 containers of 50/50 mix (most of it before the new cap...)

How would you suggest I burp the coolant?

What causes it?

Resevoir for the coolant? It was empty when I checked this. Before this it was stable and not leaking anywhere (after the new cap - before new cap it would leak out of the coolant fill cap as it was tilted and cap had bad rings)

Yes it's the crappy ss I bought a while back.

What am I looking for with the turbo and oil cooler?

 

They both have water/oil interfaces.
You could get away with a few thousand dollars for a brand new engine, instead of pouring time and money into a black hole.

 

Like this how too!

https://www.chevyhhr.net/forums/how-...-system-60614/

 

If the coolant is disappearing, is the oil pan fuller? What does the oil dipstick show?