EGR Delete on Diesel Trucks: The Complete Science-Based Guide (2025)

🛒 Parts Used in This Guide

2013-2018 6.7L Dodge Ram Cummins Cooler & Throttle Valve/Coo

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2013-2018 6.7L Dodge Ram Cummins Diesel EGR Plate Cooler &

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2013-2018 6.7L Dodge Ram Cummins Diesel 5″ Turbo Back Exhaus

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Should you delete the EGR system on your diesel truck? This is probably the most controversial topic in the diesel community — and for good reason. There are myths, misinformation, and outright lies floating around everywhere. So let's cut through the noise with actual science, peer-reviewed research, and real-world data.

What Is EGR, Exactly?

EGR stands for Exhaust Gas Recirculation. It's a vehicle emissions system that recirculates a portion of your engine's exhaust gases back into the intake stream to be burned again. The stated goal: reduce NOx (nitrogen oxide) emissions, which are linked to acid rain, respiratory issues, and smog formation.

Here's the chemistry in 30 seconds: NOx forms whenever you have sufficient heat in the presence of oxygen and nitrogen. Your combustion chamber hits temperatures over 2,200°F during the combustion cycle — that's hot enough to create NOx. EGR reduces peak combustion temperatures and displaces oxygen with inert exhaust gas, which cuts NOx production by approximately 75–80% at full load. That's a significant reduction backed by real-world SAE and scientific testing.

How EGR Actually Works (The Science)

Most people think EGR "burns off" NOx. That's wrong. EGR prevents NOx from forming in the first place, and it does this through two mechanisms:

1. Reducing Available Oxygen

Exhaust gas is inert — its oxygen has already been consumed in combustion. When recirculated back into the intake, it dilutes the oxygen content of the intake charge. In a diesel engine, this is less of a problem than you might think. The stoichiometric air-fuel ratio for diesel is 14.5:1, but diesels typically run at 20:1 or even 70:1 air-fuel ratios. There's always more oxygen than needed, so displacing some oxygen with inert gas barely affects power output.

2. Lowering Combustion Temperature

This is where it gets interesting. You might expect pumping hot exhaust into the intake would make things hotter — but that's not what happens. The EGR gas has a higher heat capacity than ambient air. Think of it like this: if you drop a hot object into water versus oil (same mass, same temperature), the water's temperature rises less because water has a higher heat capacity. The same principle applies in the cylinder — the higher heat capacity exhaust diluting the intake charge means the combustion doesn't reach as high a peak temperature.

Lower peak temperature = less NOx formation. It's that simple.

3 Major EGR Myths Debunked

Myth #1: "EGR reduces emissions"

False. EGR reduces NOx specifically — not total emissions. If your diesel truck produces 25 pounds of exhaust per gallon of diesel without EGR, it produces 25 pounds with EGR. The volume is the same. Only the NOx content changes. Soot, carbon monoxide, and hydrocarbon emissions can actually increase with EGR.

Myth #2: "EGR burns off harmful pollutants"

False. EGR is not designed to reburn exhaust to eliminate pollutants. The slower, cooler combustion can incidentally burn some remaining hydrocarbons, but that's a byproduct — not the goal.

Myth #3: "The EPA mandates EGR systems"

False. The EPA doesn't mandate EGR. It sets maximum NOx output limits. OEMs then choose the most economical strategy to meet those limits, which is typically EGR. Some manufacturers, like Cummins with the 2004.5–2007 5.9L, used internal EGR built into the camshaft at no extra cost. If you're wondering why your 2006 Cummins only gets 16 MPG, now you know.

Effects of EGR on Diesel Engine Performance

Based on peer-reviewed research from SAE and the journal Energies, here's the full picture:

EGR and Engine Wear: What the Research Actually Says

This is the $64,000 question: does EGR actually destroy your engine?

According to SAE technical paper 1999-01-0839 ("The Effects of EGR on Diesel Engine Wear") and peer-reviewed studies in the journal Energies, here's what controlled testing shows:

• High-load operation with EGR — increased wear on piston rings and cylinder liners (2nd, 3rd, and oil control rings wear faster)
• Low-load/cruise operation — EGR had negligible effect on wear in lab testing
• Aged oil + high EGR — dramatically worse wear. But "aged oil" in the study meant oil that was degraded far beyond what you'd see at 15,000–20,000 miles — we're talking 55,000+ mile equivalent
• Modern ultra-low sulfur diesel (ULSD) — better for engine wear than the higher-sulfur fuels used in older studies

The research conclusion is nuanced: EGR can increase engine wear in worst-case scenarios, but the difference is unlikely to be meaningful for most owners. The engine with a functioning EGR will likely outlast your desire to keep driving the truck anyway.

Your EGR Options: Keep, Optimize, or Delete

Regardless of where you stand on the EGR debate, here are your actual options — ranked from least to most aggressive:

Option 1: Keep It Stock

For most truck owners, this is the most practical choice. Keep the EGR system maintained, use quality oil and filters, and change oil at reasonable intervals. Consider running used oil analysis (UOA) every few changes to monitor soot content in your oil — that's the real indicator of how EGR is affecting your oil. Any API-certified diesel oil (including budget options from Walmart) meets the necessary specifications.

Option 2: Tune It Out

Many tuners and aftermarket performance companies offer tunes that reduce EGR demand or disable EGR entirely through the ECU. Some OEM manufacturers (looking at you, Volkswagen and Cummins) have done exactly this — and faced millions in EPA fines. Tuned-out EGR can improve fuel economy and reduce soot accumulation, but it affects your emissions compliance status.

Option 3: Block It Off

Block-off plates prevent exhaust gases from flowing through the EGR system. The EGR hardware remains physically on the engine (appears stock), but the system is effectively disabled. This eliminates EGR flow without making dramatic visible changes. The downside: you're still carrying around dead weight, and the EGR cooler remains a potential coolant leak point.

Option 4: Camshaft Swap (2004.5–2007 Cummins 5.9L Only)

This is a unique case. The 2004.5–2007 5.9L Cummins uses internal EGR — built into the camshaft profile via valve overlap. Swapping to an aftermarket camshaft eliminates internal EGR without removing any external components. Benefits include better fuel economy, less smoke, and potentially longer engine life — though your transmission will still need attention every 100,000 miles (that's just the 48RE life expectancy).

Option 5: Full EGR Delete

Remove all EGR hardware: EGR valve, EGR cooler, piping, hoses, and associated sensors. An EGR system can't produce NOx if it doesn't exist. This is the most aggressive option and provides the most performance benefit.

⚠️ Important: Deleting or disabling EGR without proper engine tuning can actually DAMAGE your engine. Increased combustion and exhaust gas temperatures without calibration adjustments can cause detonation, overheating, and component failure. If you delete, you need a proper tune. This also affects your vehicle's emissions compliance — check your local and federal regulations before proceeding.

🛠️ Related Maintenance Parts - Grab While You're Wrenching

Since you're already working on your truck, these maintenance items take minutes to swap while everything's apart:

2013-2018 6.7L Dodge Ram Cummins Diesel 5″ Turbo B

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2013-2018 6.7L Dodge Ram Cummins Diesel EGR Plate

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2013-2018 6.7L Dodge Ram Cummins Diesel EGR Plate

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Frequently Asked Questions

Does EGR delete void my warranty?

It can, yes. Removing emissions equipment may void warranties related to emissions components. However, many states protect your right to repair and maintain your own vehicle. Check your local laws.

Will EGR delete improve my fuel economy?

Most owners report a 0.5–2 MPG improvement after a proper EGR delete with tuning. Your results will vary based on driving style, load, and tune quality.

What's the cost of an EGR delete kit?

EGR delete kits for common diesel trucks (Cummins, Duramax, Power Stroke) range from $150 to $600 for parts. If you need a shop to install it with a tune, budget $800–1,500 total.

Can I pass emissions testing with an EGR delete?

In most U.S. states, no. However, Alaska, and many counties in other states don't require emissions testing. If you live in a state with no emissions requirements, this is a non-issue.

Does EGR delete cause overheating?

Properly tuned EGR deletes don't cause overheating. If you delete EGR without retuning the engine, you may see higher exhaust gas temperatures (EGT). A good tuner will address this in the calibration.

What about 2013+ diesel trucks with DPF and SCR?

Full emissions deletes on 2013+ trucks are significantly more complex and expensive because you need to address EGR, DPF (Diesel Particulate Filter), and SCR (Selective Catalytic Reduction) systems. The costs and complexity are much higher, and these systems are heavily monitored by the OEM's engine control systems.