Wow! Thanks for all the great responses. I'll try to reply to each:
...Then do a "citric acid flush" and see if that cleans anything out. ...
I just Binged that and will read up on it. Thanks for the confirmation on water flow and the tip.
... If the heater core lets go the interior could be in for a world of hurt or perhaps worse a slow leak you don't notice until the carpet has been soaked and mildewed. Being in the PNW (I lived in Seattle for 15 years) they'll need the heater and particularly the defroster for a good part of the year. Might be a good time to replace or rebuild the heater system anyway. ...
You are right about the need for the heater/defroster. Luckily the previous owner had just replaced it and it had been doing the slow leak as you describe.
... Yes, that is the reason why you need to use demineralized water in your cooling system. ...
Crazy... I have a stalagmite growing in the engine.
If the engine was running and the build-up wasn't that bad, you probably could have gotten away with doing a series of strong flushes. But from what I see there, I would hot tank the engine and have the shop check the measurements while installing new cam bearings.
The engine was/is running; I drove it ~40 miles home upon purchase.
... Evaporust/Thermocure will eat that stuff away and turn it to a powder like that can be carried away, it has to be immersed completely though. ...
Carried away by the water pump? Are you suggesting Evaporust in the cooling system while running?
But for this one, I would drop that cruddy sucker off at the machine shop and tell them to:
hone cylinders (bore if needed)
hone crank bearings (bore if needed)
replace cam bearings
measure and recommend new crank bearings
Check the valve seats and regrind if needed
Replace valve guides and machine for posi-seals
Check the crank if you are reusing
Press pins for pistons and arms
Measure and recommend bearings for connecting rods
I know all the engine work sounds like alot, but this is pretty basic stuff for any machine shop. You should be able to walk out the door having spent less than 600 or so. ...
You're right, it does sound like a lot... but $600 seems very reasonable for all that; I was thinking much higher. I'll see if a local shop will come close to that price.
Thanks again for the responses.