904-5021 | Genuine Dorman® EGR Exhaust Gas Recirculation Cooler

1. Cools Exhaust Gas

Hot exhaust gases are passed through the cooler, where coolant absorbs the heat.
This reduces the gas temperature significantly.

2. Lowers Combustion Temperatures

When the cooled exhaust gas is mixed with the fresh air entering the engine:

• The peak combustion temperature drops

• This reduces harmful NOx (nitrogen oxide) emissions

3. Protects the Engine

Cooler exhaust gas helps prevent:

• Engine knock

• Overheating

• Premature wear on engine components

• One of the most common symptoms

• Caused by coolant leaking into the exhaust system and burning off

• Smoke often has a sweet smell

2. Coolant Loss With No Visible Leak

• Coolant level drops over time

• No external drips because coolant is leaking inside the EGR cooler and going out the exhaust

3. Engine Overheating

• A failed cooler disrupts coolant flow

• Can cause the engine to run hot or overheat under load

4. Check Engine Light or EGR Codes

Common fault codes include:

• EGR flow insufficient

• EGR cooler efficiency

• EGR temperature sensor problems
  The ECM detects abnormal gas temperatures or incorrect EGR flow.

5. Poor Engine Performance

• Reduced power

• Rough idle

• Turbo lag

• Hesitation during acceleration
  If the cooler is clogged with soot, EGR flow becomes restricted.

6. Excessive Exhaust Back Pressure

• Caused by a clogged EGR cooler

• Can trigger turbo-related faults

• May cause the engine to run louder than usual

7. Sweet Smell From Exhaust

• Coolant entering the exhaust produces a sweet, antifreeze-like odor

8. Steam Coming From Exhaust

• Severe coolant contamination can create steam clouds, especially on startup

9. Contaminated Coolant

• Oil or soot mixing into coolant

• Coolant turns dark or sludgy