/6 Cooling System: Multiple Cleanings

FWIW.... the photo here is of the coolant in a /6 that was just rebuilt 700 miles ago. Nothing wrong, just that it has dirtied up pretty quickly. This engine had a ton of sludge in it from setting with little driving for years with no real work to keep the cooling system clean. During the rebuild, the block was not only hot tanked but also acid tanked to help clean out the cooling passages. Yet 'stuff' is still being cleaned out from it.

So, if you have an old /6 that has not been run much, you may want to do several cooling system cleanings and coolant renewals over the course of many months or a year; one 'treatment' will not likely do it.

BTW this coolant is the G05 stuff, which is nearly clear when new. Hence, the lack of green tint.