ELC are usually premixed but will say on the container. Most shops cannot check the PH levels on ELC coolants. The old strips don't work the same. I got this info from both CAT and a large Pete dealership that does a lot of CAT warranty work. They do have a way to check it but it requires a mechanic to mix enough chemicals and screw around long enough that they won't do it unless you're willing to pay extra. BTW there is a chemical that you put in the ELC to renew it half way through it's life. On the subject of filters CAT pm kits used to come with water filter that I would install at oil changes and then do the strip test. Later they came with a bottle of additive that you were supposed to add if you needed to. I personally think no two CAT dealerships know what the other is recomending LOL