Removing Rust from Cooling System

[SmithKid]

Probably wouldn't be a bad idea to perform a regular electrolysis check too. Particularly if there is any aluminum in the cooling system.

[BPVan]

Since the cooling system is apart anyway, I am going to try flushing manually with a coolant system cleaner and using a brush wherever I can reach. I am going to pull the block drain as well as thermostat housing and see how much crud I can remove.

I like Jeff's idea as well and will do so after a good manual cleaning of the components while it is apart. The good news is that when I drained the system the radiator seemed to have free flow.

[Luva65wagon]

Just be careful not to get water down the oil holes...

[BPVan]

I heeded all warnings. I carefully flushed the block and radiator with hot water until it came out clear. I am going to pull the thermostat housing and water pump to carefully clean them, run hot water through the heater core, then call it good until reassembly. The freeze plugs look good and all else seems to be checking out.

[Luva65wagon]

Hmm... and all this time I thought your motor was pretty new. Not sure why I thought that, but the picture would indicate otherwise.

That looks pretty normal for water-only coming from a block. Left there overnight fresh water would do the same. Lots of raw cast-iron in the water jackets. Takes no time at all to turn brown. That's why you add green.