Sorting Out Your 4bt Cummins Thermostat Issues

Swapping out a 4bt cummins thermostat isn't exactly the most glamorous way to spend a Saturday afternoon, but it's one of those small jobs that can save you from a massive headache down the road. If you've ever owned one of these 3.9-liter workhorses, you know they're basically bulletproof, but they do have a few quirks when it comes to temperature management. Whether you're running one in a bread truck, a swapped Jeep, or a piece of farm equipment, keeping that coolant flowing correctly is the difference between a happy engine and a warped head. ...

May 2, 2026 · 6 min · Radzko Gillman