how clean radiator.

[67_camaro]

I started my 396 for the first time in a couple months and when I checked the radiator, the water was all dirty and I recently put new coolant. The coolant was very dirty. How can I clean the radiator and the block.? Does anybody know

[sam 74]

cooling system flush from a local auto store should work, gonna be a bit messy though.

[rohrt]

vinegar will work but don't run it very long.

[MonzaRacer]

Honestly hit a rural king, buy a gallon of simple green concentrate, drain it out, recycle AF, fill with water, run, drain again. Add about 1qt to 1/2 gal of simple green, fill with water and let run for 1/2 to 1 hr, idle is fine just dont let overheat.
Then stick water hose in rad, turn water on slow with drain open, keep it full as water just dribbles out neck, flush for about 10 to 15 minutes with car running, try to get electric fans too cycle if controlled from engine sensor and by computer, if using other controller, ignore fan run. Flush till clear water comes out petcock, close it, leave filled with water and go for short 15 to 30 minute drive, then come back, let drain down, top off with full strength AF.
If using over counter stuff look for the Ford Extended life G-05 version.
Drive few days and check concentration, drain down and top off as needed to get freeze protection (ie at least 50/50) keep what you drain out and use too dilute rest of AF for future use.
I like to swap Tstats ,if car is driven lot, every spring, top off with fresh 50/50. Then your ready for summer and the next winter. Reason why is stats operate open to close more in winter, in summer they open and pretty much stay open till engine cools off, little wear in summer.
We used to do the Simple Green for diesels and for vehicles with oil contamination, works great.