Originally Posted by MOSTWANTED
So I am considering flushing the coolant soon and have been trying to read up on it. I found a few write ups on it and plan to buy the napa coolant flush kit. The one thing I'm not clear on is the type of coolant required for the early 99 engine. I was reading that the early models have different requirements than late 99 and newer. What exactly should I be looking for? Any other tips on this is appreciated.
Does the truck have the original injectors?
E99 trucks use a different sealant on the injector cups than the late 99+ and therefore the 2-EHA found in most OAT coolants (like coolants meeting Cat EC-1) can eat the sealant on the cups and cause an injector cup failure.
Now if the truck had its injectors changed there is the possibility they changed the sealant but it is not a sure thing.
For simplicity sake you could get a pre-charged coolant like Fleet Charge or Napa's fleet coolant or you could get some plain old green coolant (meeting ASTM D4985) and add SCA (supplemental coolant additives, designed to fight cavitation aka pitting of the cylinder walls). I like Cummins DCA 4 as an SCA, very effective and you can use less of it compared to a DCA 2 like Napa Kool.
Supplemental Coolant Additives (SCAs)