I’m a car nerd and a hobbyist mechanic learning by getting my hands dirty. I picked up a 2003 Forester, Pacifica Blue with ~170k, bone stock, a great body and interior, and one big issue – overheating.
After pulling the engine I found that some of the coolant passages were plugged solid. Mystery solved. It’s a bit crude but the attached picture features a flathead screwdriver stuck into the calcification – that’s how dense it is. I have to assume the smaller internal passages are just as bad, though the water pump itself was clean and the passenger's side passages aren't *as* bad.
I was told phosphoric acid cleaner would eat away at it, but would it really get it all? I know the most effective way would be to pull everything and have the block hot tanked. I’m worried I’ll jump into a money pit of pistons / rings / bearings if I go that route. The engine ran well, and I can still see factory crosshatching on the cylinder walls. IMO they don't look bad but other people say they do. It might get headers and exhaust some day but it will most likely remain totally stock.
I have head / intake / exhaust / oil pan / valve cover gaskets, rear main seal, head bolts, thermostat, timing belt, water pump, and more waiting to go on.
I’m pondering my options before the heads go to the machine shop. Because of new circumstances I need this to be my daily driver, so I'm trying to save money. On the other hand, I want to do things properly and reliably the first time. Advice has ranged from “chip away what you can” to “buy a different block” ... what would you do?
High-res images here https://imgur.com/a/eGBDm
Edit: attached another image - is that oil weeping past the rings?
Edited by Dake, 13 February 2018 - 05:13 PM.