Diagnostics · Expert tip
What to Check When Your Diesel Engine Won't Start
A diesel engine needs fast cranking speed, clean fuel, and heat to fire up. Use these quick starting troubleshooting checks to isolate the issue fast when your diesel engine won't start.
The expert tip
- Check the glow plug indicator on the dash and wait 3 to 5 seconds after it turns off before cranking in cold weather.
- Pump the manual fuel primer on top of the fuel filter 10 to 15 times until it feels firm to bleed out trapped air.
- Verify that your battery voltage stays above 9.6 volts while cranking, as diesels need high cranking speed to build compression heat.
- Inspect the fuel filter drain valve for trapped water or ice blockages when temperatures fall below 0 degrees Celsius.
- Turn the ignition key to the run position and listen for the electric fuel lift pump operating for 2 to 3 seconds.
Source: Workshop best practice
Apply tips that match your car and manual. For anything safety-critical or high-voltage, use a qualified mechanic.