I bought this car on 9/3/2003 and am very impressed with it. Really I am not complaining. It is a great car. I love the 210 hp 3.4 L DOHC engine.
I checked the engine coolant and saw that it was BROWN! I decided to get a Prestone Back Flush Kit and back flushed the entire cooling system for 30 minutes. I then put in a bottle of Prestone Super Radiator Cleaner and ran it with just water for 5 hours of on and off driving. I then back flushed the entire system again for 30 minutes, took out the overflow tank and cleaned it, and replaced the thermostat.
I didn't know what antifreeze to use so I put in about 2 jugs of Prestone Extended Life 5/150 Antifreeze (Red DEX-COOL). I was smart enough to look through the whole owners manual for the car and it didn't say anything about DEX-COOL, but it didn't say anything about just plain green coolant either. All it said was to use a coolant that met GM Specification 1825-M. Both Prestone green and red meet this specification.
My question is which coolant did my car come with? If it did come with green, should I go back to green after putting in the red? I am gonna try calling a few parts departments at Pontiac dealerships to find out. If it is green, it won't bug me much to back flush the system again for 30 minutes, run Prestone Super Radiator Cleaner through it again for 5 hours, back flush again for 30 minutes, replace thermostat, clean out overflow tank, and fill up with Prestone green.
Thanks In Advance, BTJustice