I made a quick video of how to check if EGR Cooler is bad. This one was by far the worst Ive seen, 1 gallon in about 2 days. Don't let it get this far. This customer drove it for 4 months losing coolant and didn't give it much thought. Fortunately he didn't need a DPF, just a Cooler and Valve and a couple sensors. Let me know if you want to see me make a video on something else. Stay tuned for more. Thanks for watching.