The exhaust gas recirculation (EGR) cooler cools part of your diesel's exhaust before it goes back into the intake. That lowers combustion temperatures and cuts nitrogen oxide (NOx) emissions. Over time, soot and carbon coat the inside of the cooler, so it flows less exhaust and cools it less.
Here are the signs that an EGR cooler may need cleaning, and the signs that point to a bigger problem.
1. Lost Power and Slow Throttle Response
A plugged EGR cooler restricts exhaust flow and upsets the air-fuel balance the engine control module expects. You may notice sluggish acceleration, more turbo lag, trouble holding speed on hills or a derate.
2. EGR Fault Codes
Common codes tied to EGR cooler flow or performance include:
- P0401 – EGR flow insufficient
- P2457 – EGR cooling system performance
- P0404 – EGR circuit range or performance
These codes can also come from a sticking EGR valve, a failed sensor or a vacuum or wiring problem. Have the system diagnosed before pulling the cooler. Heavy-duty engines may show manufacturer-specific codes instead.
3. High EGR Temperatures
If the cooler is coated inside, it can't pull enough heat from the exhaust. The EGR outlet temperature climbs, and the engine may set a code or reduce EGR flow to protect itself.
4. More Soot and Frequent DPF Regens
When EGR flow and cooling are off, combustion produces more soot. That loads the DPF faster, so you may see more regens or a DPF that needs cleaning sooner than usual.
5. Rough Running and Unusual Sounds
A restricted EGR system can cause rough idle, stumbling or uneven running under load. Hissing or ticking near the EGR cooler or its pipes often points to an exhaust leak at a joint or gasket. Noises can come from many sources, so have them diagnosed instead of assuming it's the cooler.
When Cleaning Won't Fix It: Signs of a Leaking Cooler
Cleaning removes soot and carbon. It can't repair a cooler that leaks coolant. Stop and have the cooler pressure-tested if you notice:
- Coolant loss with no visible external leak
- White smoke with a sweet smell from the exhaust
- Coolant in the intake or exhaust, or a coolant-soaked DPF
- Bubbles or pressure in the coolant reservoir
A leaking EGR cooler can damage the engine and contaminate the DPF, so it needs repair or replacement, not cleaning.
Our EGR Cooler Cleaning Service
We clean EGR coolers for $300, with 48-hour turnaround once the cooler arrives. Drop off at our cleaning plant at 215 Ullery St, Unit 2, South Bend, IN 46637 and pick it up when it's ready to save $25 per item, or call to ship it in. Many customers send the DPF, DOC and EGR cooler together. See all our cleaning services.
Frequently Asked Questions
How long does EGR cooler cleaning take?
48 hours once the cooler arrives at our cleaning plant.
How much does EGR cooler cleaning cost?
$300. Save $25 when you drop it off and pick it up at our cleaning plant.
Should I clean the DPF at the same time?
If the EGR cooler was plugged, the DPF has likely been collecting extra soot. It's a good time to check it. DPF cleaning is $300 with a 24-hour turnaround.
Talk to Us About Your EGR Cooler
Call 574-213-8691 or email dieseldpfcleaning@gmail.com, Monday–Friday, 10 a.m.–5 p.m. Eastern. Have your engine make and model, the cooler part number and any fault codes ready.