An L5P EGR delete kit removes or bypasses the exhaust gas recirculation system on a Duramax L5P diesel engine
The L5P is the diesel engine in 2017 and newer Chevrolet Silverado and GMC Sierra trucks. The EGR system recirculates a portion of exhaust back into the engine to lower combustion temperatures and reduce certain emissions. An EGR delete kit physically removes this system or blocks it so exhaust no longer flows back into the intake.
People install these kits because they believe the EGR system reduces engine performance, increases maintenance costs, or causes reliability problems over time. The kits range from straightforward bolt-on components to full system replacements that require welding or machine work. Installation difficulty and cost vary widely depending on which kit you choose and whether you do the work yourself or pay a shop.
Before buying or installing any EGR delete kit, you should understand what the system does, what removing it changes about your truck, and what legal and warranty consequences might follow.
Key Takeaways
- An EGR delete kit removes or blocks the exhaust gas recirculation system, which normally recirculates exhaust back into the engine to reduce emissions.
- Owners report that deleting the EGR can improve throttle response and reduce carbon buildup inside the engine over time.
- Removing the EGR system may trigger a check engine light and will likely void your truck's powertrain warranty.
- EGR delete kits are not street-legal in most states because they alter emissions systems, and using one can result in inspection failure or fines.
- Installation costs range from a few hundred dollars for straightforward kits to over $1,000 if welding or machine work is required.
How the EGR system works on the L5P engine
The EGR system on the L5P pulls a small amount of hot exhaust gas from the engine's exhaust manifold and routes it back into the intake manifold through a cooler. This recirculated gas mixes with fresh air and fuel before combustion. Because exhaust gas is inert and already burned, it lowers the peak temperature inside the cylinder during combustion.
Lower combustion temperatures reduce the formation of nitrogen oxides (NOx), a regulated pollutant. The trade-off is that cooler combustion can slightly reduce power output and efficiency. The EGR cooler itself is a heat exchanger that cools the recirculated exhaust before it re-enters the engine, and it requires regular cleaning because carbon deposits build up on its internal surfaces over time.
On the L5P, the EGR system is integrated with the engine control module and emissions monitoring. If the system malfunctions or is removed, the engine computer detects the change and stores a diagnostic trouble code, which illuminates the check engine light on the dashboard.
What changes when you delete the EGR system
Removing the EGR system stops exhaust from recirculating, which means combustion temperatures rise and the engine burns fuel more completely. Many owners report sharper throttle response and a slight increase in power output, though the gains are usually modest on a stock engine. Some also report that carbon buildup inside the engine decreases because exhaust is no longer being reintroduced into the cylinders.
The EGR cooler is no longer needed after deletion, so you eliminate the maintenance associated with carbon cleaning on that component. However, you are also removing a system that was designed to meet federal emissions standards, and the engine will run hotter during certain operating conditions.
The most when ready change is that the check engine light will come on. Some delete kits include a tuning solution that reprograms the engine computer to ignore the missing EGR signal, while others straightforward remove the hardware and accept the light. A few kits use a mechanical block-off plate without any electronic modification.
Types of L5P EGR delete kits and installation complexity
EGR delete kits fall into three broad categories. Block-off plate kits are the simplest: they use a metal plate to seal off the EGR cooler inlet or outlet, preventing flow without removing any components. These typically cost $200 to $400 and can be installed in a few hours with basic hand tools, but they do not address the check engine light.
Cooler delete kits remove the EGR cooler entirely and reroute or block the EGR lines. These require disconnecting coolant hoses, fuel lines, and electrical connectors, and they usually cost $400 to $800. Installation takes a full day and requires moderate mechanical skill. Many of these kits still trigger the check engine light unless paired with a tuning solution.
Full delete kits with tuning remove the EGR system and include a custom engine tune that disables the EGR monitoring in the engine computer. These are the most expensive option, ranging from $800 to $1,500 or more, and they require either mail-in tuning or a visit to a shop with tuning software. Some kits require welding to modify exhaust or intake piping, which adds labor cost if you do not have welding equipment.
Check engine light and engine computer changes
When you delete the EGR system, the engine computer expects to see a signal from the EGR valve or cooler temperature sensor. If that signal disappears, the computer stores a diagnostic trouble code and illuminates the check engine light. This light does not mean the engine is damaged or unsafe to drive, but it does indicate that the computer has detected a change from the factory configuration.
Some delete kits include a custom tune that reprograms the engine computer to stop monitoring the EGR system entirely. This prevents the check engine light from coming on and allows the engine to run without the EGR system active. Custom tunes are usually delivered via a handheld tuner device that connects to the truck's diagnostic port, or they are installed by a shop using specialized software.
If you install a delete kit without tuning, you will have a permanent check engine light. Some owners accept this, while others find it unacceptable because it makes it harder to spot other problems. A few shops offer a "code delete" service that disables the check engine light through tuning, but this does not address the underlying emissions system change.
Warranty and legal considerations
Installing an EGR delete kit will void your truck's powertrain warranty. Chevrolet and GMC can refuse to cover engine, transmission, or emissions-related repairs if they determine that the deletion caused or contributed to the failure. Even if the failure is unrelated to the EGR system, the manufacturer may deny the claim based on the modification alone.
EGR delete kits are not street-legal in most states because they alter the emissions control system. Federal law prohibits removing or disabling emissions equipment on vehicles intended for road use. Many states conduct emissions inspections as part of vehicle registration or safety testing, and a truck with a deleted EGR system will likely fail that inspection. Fines for emissions violations vary by state but can range from several hundred to several thousand dollars.
Some owners install delete kits on trucks used only off-road or on private property, where emissions laws do not explore. If you plan to use your truck on public roads, you should be aware that the modification is illegal and that you assume the risk of inspection failure, fines, or other enforcement action.
Cost breakdown for parts and labor
The total cost of an EGR delete depends on which kit you choose and whether you install it yourself or hire a shop. A basic block-off plate kit costs $200 to $400 and requires no labor if you do the work yourself. A cooler delete kit without tuning costs $400 to $800 in parts, plus $300 to $600 in labor if a shop installs it. A full delete kit with custom tuning costs $800 to $1,500 in parts and tuning, plus $200 to $400 in labor for installation if welding is required.
If you do not have welding equipment or tuning software, you will need to pay a shop for those services. Welding typically costs $100 to $300 depending on the complexity of the work. Custom tuning through a mail-in service costs $200 to $400, while in-shop tuning may cost $300 to $600. Some shops bundle the kit, installation, and tuning into a single package price, which can be more economical than buying and paying for each service separately.
Frequently Asked Questions
Will an EGR delete damage my L5P engine?
Deleting the EGR system does not inherently damage the engine, but it does change how the engine operates. Combustion temperatures rise, which can increase wear on internal components over very high mileage. Many owners report no problems after thousands of miles with a delete kit installed, but long-term durability data is limited because the L5P is relatively new.
Can I pass emissions inspection with an EGR delete?
No. An EGR delete removes a required emissions control system, and most states will fail a truck with a deleted EGR during inspection. Some states do not conduct emissions testing, so you may be able to register a truck with a delete kit in those states, but federal law still prohibits the modification on road-use vehicles.
Do I need a custom tune to delete the EGR?
No, but without a tune you will have a permanent check engine light. A tune disables the EGR monitoring in the engine computer and prevents the light from coming on. Many owners consider a tune essential for this reason, even though it adds $200 to $600 to the total cost.
What is the difference between a cooler delete and a full delete?
A cooler delete removes the EGR cooler and blocks the EGR lines, but the EGR valve may still be present. A full delete removes all EGR components, including the valve, cooler, and lines. Full deletes are more thorough but also more labor-intensive and expensive.
Will deleting the EGR improve my fuel economy?
Most owners report little to no change in fuel economy after an EGR delete. Some report slight improvements because combustion is more efficient, while others see no difference. Fuel economy depends on driving habits and conditions more than on the EGR system, so results vary widely.