Get a bottle of radiator flush from a local autoparts or hardware store and follow these steps;

- drain old coolant and water.
-put radiator flush in, fill radiator with water
-run motor 10 minutes at least
-drain radiator
-fill radiator with water, run 10 minutes, drain
-repeat
-fill radiator with new water + coolant
-during all these steps have heater on full blast

 

WEll, I'd just follow the manufacturere's instructions if you are using something like Prestone products. Some are acidic and require a neutralization process. Best way by far is to have it done at a reputable radiator shop. They have the stuff and most importantly the know-how.

My $0.02

 

Yeah, shops will remove the thermostat FIRST, then backflush after soaking chemical solution. The main thing is that they will have the proper recovery equipment to catch all the 'stuff'. EPA and or city may come down on you if someone complains.... just a thought.

 

Originally posted by Moloko:
Get a bottle of radiator flush from a local autoparts or hardware store and follow these steps;

- drain old coolant and water.
-put radiator flush in, fill radiator with water
-run motor 10 minutes at least
-drain radiator
-fill radiator with water, run 10 minutes, drain
-repeat
-fill radiator with new water + coolant
-during all these steps have heater on full blast

I agree with this almost. On SOME products they require you use a cleaner first, THEN use the flush to neutralize the remaining cleaner that is in the block and RAD. Read the directions, people use the terms flush and cleaner as the same they are not.

 

Don't forget to open the block drains when you're done to remove the last gallon of contaminated water.