I had the check engine light come on yesterday (4/6/22) and pulled into O' Reilly Auto Parts to have them check the code. The code was for the crankcase breather being disconnected. We opened the hood and looked around, finding nothing obvious was disconnected. However, noticed that the coolant reservoir was dirty looking and removing the cap allowed me to see globs of oil floating around. I pulled the engine oil filler cap and the underside was coated in gray sludge. Now, I'm no mechanic and I'm sure as hell not a diesel mechanic, but I know what oil and water look like when mixed together. From everything I've read I suppose I'm in need of a new oil cooler. Waiting for the tow truck now and was wondering if anything has been done to improve the oil coolers, or will I be simply waiting for this to happen again in the future. My truck is a 2018 with just under 25,000 miles.