The intake grid heater is how the Cummins warms incoming air for cold starts, and on the 6.7L it also carries a well-known safety concern with its mounting bolt.
What it does
Instead of glow plugs, the Cummins uses an electrical grid heater in the intake that warms the air entering the cylinders. It draws high current and helps the engine start cleanly in cold weather while reducing startup smoke.
Signs it is failing
- Harder cold starts if it fails
- Grid-heater electrical fault codes
- A rattle from the intake if hardware loosens
- Longer cold crank times
Replacement and what to know
The grid heater itself rarely fails, but on the 6.7L the power-stud nut can loosen and the bolt can drop into the intake, risking engine damage. Many owners install a secured, updated assembly or a warm-climate spacer to eliminate that risk. Keep a functioning heater if you start in cold weather.
Frequently asked questions
Do Cummins engines have glow plugs?
No. The Cummins uses an intake grid heater to warm incoming air instead of glow plugs.
What is the grid heater bolt concern?
On the 6.7L the power-stud nut can loosen and drop the bolt into the intake, so many owners secure or replace the assembly.
Should I keep the grid heater?
Keep a working heater if you start in cold weather; a warm-climate spacer is an option where cold starts are not a concern.
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