Re: Any info on changing the coolant and filter?
SCA's are supplemental coolant additives. The reality of it is that if you use an automotive type green (ethylene glycol) coolant meeting ASTM D-3306 and the filter you should be ok. Most of the filters have the SCA's in them already and will slowly release it. However, if you use a "heavy duty" coolant meeting ASTM D-4985 specs you will have to add the SCA's. If you use heavy duty coolant meeting D-6210 you will be ok as well.
Using the ASTM D-3306 sounds like the easiest method, right? Well it is, but it isn't the right way to go. Regular coolant contains a pretty stiff dose of silicates. That's great for protecting aluminum in modern car engines, but doesn't do so great 9in heavy duty applications. Instead, you use the heavy duty coolant and mix it with the appropriate SCA and water to make a coolant mixture that is low in silicates, but high in SCA's to prevent cavitation. That's especially important on sleeved engines although some of our sleeveless designs also suffer from cavitation issues. I have heard that the 6.9/7.3/T444E Internationals are prone to cavitation, as is the 6.6/7.8 Ford.
Ok, it's all getting pretty technical and probably won't matter, but what's my recommendation? Get a fully formulated coolant meeting the D-6210 specs. That will have the proper SCA's in it already and will just need to be mixed. Any automotive store worth looking at will have plenty of it on hand, usually in a jug that says, "Heavy Duty," or, "Fleet," somewhere on the bottle. That combined with your filter which more than likely has an SCA package built in will keep your engine alive and happy for a long time.