Emissions
EGR Cooler
The EGR cooler chills recirculated exhaust gas so it lowers combustion temperature more effectively.
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Emissions flow
Interactive — tap a partTap a part to see how it fits in the system.
What it does
- Cools exhaust gas before it returns to the intake
- Improves NOx reduction on diesels
- Part of the EGR circuit
When it fails
- Loss of power
- EGR codes
- Coolant loss (leak into the cooler)
- Black smoke
How to diagnose
- Pressure-test for internal leaks
- Check for coolant in the intake
- Inspect for carbon blockages
Maintenance
- Fix coolant leaks early
- Clean or replace when blocked
Use the diagnosis order. When a part fails, confirm each hypothesis with measurements before replacing anything — codes and symptoms overlap.