I need to know what is the best way to flush out a radiator.. or rather what is the best cleaner to flush out the crud from my fairly new aluminum radiator..other than the junk they sell at the zone type stores..I remember years ago we used a arm & hammer type of cleaner that worked great !! Any suggestions ??Thanks 56 Plymouth 493 cid..P/S rad will be out of the car ..

White vinegar.

What did you run in your fairly new aluminum radiator?

What does your gunk look like?

compressed air and water. the industry standard.

I used the green Prestone and water...no additives..The crud is brown rust color and seems pasty on inside of radiator cap and hoses ..runs cool but is just plain sh#%ty

OK that's good. As long as it's not watered down. Aluminum radiators and water do not get along

If the crud is rusty that's just crud. Hopefully it's just from not being clean before hand and not a lack of rust inhibitor.

White crud is bad.

Thanks for the response guys !!It has brown crud,, ..THe anti freeze is better than 50-50.So it's not watered down.. guess it came from the block...Just wanted to know what is the best cleaner...

Iron Tite makes a cleaner that is supposed to be very good. I just ordered a bottle off of E Bay, about $25. They have a 3 part system also. I have the same problem but my crud has the white stuff. Another cleaner is Citrus Acid powder also available on E Bay, about $10. Google for mixture with water, I used that on a Nash Metro, worked good.

Mercedes has a citric acid powder flush that works pretty good,drain & flush the system,shim open the thermostat add the flush to an empty bottle & mix,drive around for a day or two,drain & flush again & add coolant,Dawn dish detergent works pretty good for oily systems.