What Coolant Does Cummins Recommend You Use (And Do You Have To?)

When it comes to diesel or natural gas engines, no one wants to mess around with cooling problems. The wrong coolant or poor maintenance can turn into costly repairs very quickly. That's why Cummins, a name trusted across the globe, has its own recommended solution to keep your engine safe and running longer. It's called PGXL Vital.

PGXL Vital coolant is the official recommendation from Cummins for all its engines, both on-highway and off-road. And it's been developed to meet the toughest internal standards — CES 14603, CES 14439, and CES 14636. That simply means it's been tested and proven to offer what Cummins calls "life of the engine" protection. Not convinced yet? Let's talk about the numbers then, shared by Cummins itself. That would be up to six years, 1.5 million kilometers, or 36,000 hours of solid performance without the need for additional additives or system extenders. Pretty impressive, right?

First off, it's a premixed solution, which means no water needs to be added. This helps avoid dilution errors during top-ups or full fills. It is made from propylene glycol, which is a big thumbs-up due to its less toxic content when compared it to the more common ethylene glycol. In simpler terms, it is safer to handle and even biodegradable, though, of course, you still shouldn't pour it down the drain. Since it doesn't contain 2-EH acids, it's also gentler on seals, plastics, gaskets, and various metals in your cooling system. That's one less thing to worry about.

Plus, PGXL Vital is free from borates, nitrites, amines, phosphates, and silicates — chemicals that can harm engine components over time. It even comes with scale inhibitors, preventing build-up on hot surfaces. When it's time for a checkup, Cummins recommends using Fleetguard test strips (CC36089) every 12 months, 250,000 kilometers, or 4,000 hours, whichever comes first. The results will help make sure the coolant is still doing its job, and your engine stays protected without overcomplicating the maintenance process.

If you're switching to PGXL Vital from another coolant, Cummins suggests doing a full flush and refill, and using Fleetguard Restore or Restore Plus to clean the system. This ensures no cross-contamination. Once it's in, using coolant filtration is recommended to reduce wear and keep things running smoothly.

You're not absolutely required to use PGXL Vital, but there are strong reasons why Cummins recommends it. Using a different coolant doesn't automatically damage your engine, but it can lead to warranty issues if something goes wrong and Cummins finds the specs didn't match. If you choose to go with another coolant, make sure it meets the exact same CES standards (14603, 14439, 14636) and is OAT-based and silicate-free. Mixing coolant brands or types — especially OAT with HOAT or IAT — can cause chemical reactions that reduce protection or clog the system.

In short, you don't have to use PGXL Vital, but you do have to be very careful if you go with something else. Matching specs, doing a full flush, and avoiding any mixing are essential things to keep in mind. Otherwise, it might cost you not just peace of mind, but your warranty and a lot of money.