you need to have nitrates in the coolant. Being an 03 you have extended life coolant.
You get test strips from napa and read the strips and add nitrates accordingly.
Even if you change the coolant you want to test the new coolant too. YOu may need sca's(supplemental coolant additives) "nitrates" added to your coolant. They(strips) also test for molybdate, but your coolant may not have any of that in the first place. Mine does but some brands do not. Their are 2 formulas of additives(dca 2 and dca 4), I got all caught up in this.Use the nitrate only strips, or if you get strips that test both just read nitrate. If you flush the coolant, you use the strips and additive from the same company so it matches, some use nitrate w/molybate and others just nitrate. Both will work. If you have to guess what you have, guess nitrate only, its safer then to add a ton of additives to bring up the molyB and overload the nitrate side in doing so.
