If you're reading this, you're likely familiar with the Cummins ISX platform. These engines have powered countless Class 8 trucks for decades, and the CM870 generation from 2002-2007 represents a significant chapter in that history. You'll find these engines in Peterbilts, Kenworths, Freightliners, Internationals, and Volvos—pretty much every major brand relied on the ISX during this era.
I've spent a lot of time around these engines, both in my own truck and helping friends with theirs. The CM870 is a robust platform, but like every diesel of its generation, it carries emissions equipment that introduces compromises. The EGR system on these early ISX engines is particularly notable—not always for the right reasons.
I recently had the chance to work with the TruckTok Stage 2 EGR Delete Plug Kit for the CM870. After installing it and running the truck for a while, I wanted to share what I learned about why this modification makes sense for these engines and what the kit actually delivers.
How it works: The EGR system taps exhaust gas from the manifold, routes it through a cooler to reduce temperature, then reintroduces it into the intake stream. This dilutes the incoming air, lowering combustion temperatures and reducing NOx formation.
The cooler design: The CM870 uses an EGR cooler that's integrated into the engine's cooling system. It's effective at its job, but it's also a potential failure point. These coolers see extreme thermal cycling—from cold start to operating temperature and back again, thousands of times over the life of the engine.
The valve operation: The EGR valve is electronically controlled and constantly adjusted based on engine operating conditions. It's a moving part in a dirty environment, which makes it susceptible to sticking and carbon buildup.
The control system: The CM870 ECM actively monitors EGR operation. It's a sophisticated system for its time, but it's also sensitive to any deviation from expected parameters.
Cooler failure: EGR coolers on the ISX can and do fail. They're subject to extreme thermal cycling, and over time, this stress can cause cracking. When a cooler fails, coolant can enter the exhaust stream or, worse, the intake.
Coolant in the exhaust shows up as white smoke and unexplained coolant loss. Exhaust in the coolant pressurizes the cooling system, leading to overheating and potential head gasket issues. Neither scenario is good, and both are expensive to fix.
Soot buildup: The recirculated exhaust carries particulate matter. That soot deposits in the intake manifold, on the valves, and in the EGR valve itself. Over time, this buildup restricts airflow and can cause the EGR valve to stick or fail to seal properly.
The heat load: The EGR cooler dumps exhaust heat into the engine coolant. That's heat the cooling system has to manage on top of the engine's own thermal load. In a heavy-duty truck already working hard, that additional heat can push cooling systems closer to their limits.
Maintenance burden: EGR systems require maintenance. Valves need cleaning, coolers need inspection, and when they fail, the repair costs are substantial—especially considering the labor involved in accessing these components on a Class 8 truck.
CNC machined billet aluminum plates: The plates are made from aircraft-grade billet aluminum, CNC milled for precision fit. This isn't cast material with potential porosity or weak spots. Billet aluminum is machined from solid stock, ensuring consistent material properties and exact dimensions.
High-temperature graphite gaskets: The included gaskets are designed to handle the extreme temperatures found in diesel engine applications. Graphite maintains its sealing properties through thermal cycles and won't deteriorate over time like some other materials.
Sealed high-pressure plug fittings: The plugs are designed to seal coolant and exhaust ports with reliability. They're engineered to handle the pressures found in these systems without leaking.
Precision manufacturing: All components are CNC laser cut or CNC machined from high-quality materials. This ensures perfect fit and eliminates the need for modification during installation.
Complete kit: The package includes everything needed for the delete—plates, gaskets, and plugs. No chasing down missing parts or improvising solutions.
Cooler intake air: With no hot exhaust gas being recirculated, the air entering the engine is significantly cooler. Cooler air is denser, which means more oxygen for combustion. That translates to more complete burning and better efficiency.
Cleaner intake tract: Without soot-laden exhaust flowing through the intake, carbon buildup is eliminated. The intake manifold, valves, and turbo inlet stay clean, maintaining airflow and performance over the long term.
Reduced cooling system load: The EGR cooler is no longer dumping exhaust heat into the coolant. That means the cooling system can focus entirely on managing engine heat rather than dealing with waste heat from emissions equipment.
Elimination of failure points: The EGR cooler and valve are complex components with moving parts and exposure to extreme conditions. Removing them eliminates the possibility of failure entirely. No cracked cooler, no stuck valve, no coolant in the intake.
Simplified maintenance: With the EGR system gone, there's one less thing to inspect, clean, or repair. For trucks that run hundreds of thousands of miles, that simplification adds up over time.
Aircraft-grade billet aluminum: This material is chosen for its strength-to-weight ratio and consistency. Unlike cast aluminum, billet has no porosity or hidden defects. CNC machining ensures precise dimensions and perfect fit.
High-temperature graphite gaskets: Graphite handles extreme temperatures better than traditional gasket materials. It doesn't crack, shrink, or lose sealing pressure over time. For connections that need to remain leak-free for hundreds of thousands of miles, graphite is the right choice.
Precision manufacturing: CNC laser cutting and CNC machining produce components with tolerances that simply aren't possible with less precise methods. This means the plates fit exactly where they need to, with no filing, grinding, or modification required.
This is not a driveway job for a beginner. It's work best done by someone familiar with these engines and equipped with the right tools.
The payoff is permanent. Once the EGR system is removed, it's gone. No more worrying about cooler failure, no more carbon buildup, no more EGR-related maintenance.
A proper delete tune is required to:
The TruckTok Stage 2 EGR Delete Plug Kit addresses these issues directly. It replaces the problematic EGR valve and cooler with precision-machined plates and plugs made from aircraft-grade billet aluminum. High-temperature graphite gaskets and quality plug fittings ensure leak-free operation.
For trucks used in off-road applications where emissions compliance isn't required, this kit offers several real benefits:
For owner-operators and fleet managers looking to improve the reliability and efficiency of their ISX-powered trucks in off-road applications, this kit represents a permanent solution to a persistent problem.
If you've deleted the EGR on an ISX CM870, what was your experience? Drop your thoughts below.
I've spent a lot of time around these engines, both in my own truck and helping friends with theirs. The CM870 is a robust platform, but like every diesel of its generation, it carries emissions equipment that introduces compromises. The EGR system on these early ISX engines is particularly notable—not always for the right reasons.
I recently had the chance to work with the TruckTok Stage 2 EGR Delete Plug Kit for the CM870. After installing it and running the truck for a while, I wanted to share what I learned about why this modification makes sense for these engines and what the kit actually delivers.
Part 1: Understanding the CM870 EGR System
The CM870 was one of the first generations of ISX engines to incorporate cooled EGR as part of emissions compliance. It's a system that works, but it comes with tradeoffs.How it works: The EGR system taps exhaust gas from the manifold, routes it through a cooler to reduce temperature, then reintroduces it into the intake stream. This dilutes the incoming air, lowering combustion temperatures and reducing NOx formation.
The cooler design: The CM870 uses an EGR cooler that's integrated into the engine's cooling system. It's effective at its job, but it's also a potential failure point. These coolers see extreme thermal cycling—from cold start to operating temperature and back again, thousands of times over the life of the engine.
The valve operation: The EGR valve is electronically controlled and constantly adjusted based on engine operating conditions. It's a moving part in a dirty environment, which makes it susceptible to sticking and carbon buildup.
The control system: The CM870 ECM actively monitors EGR operation. It's a sophisticated system for its time, but it's also sensitive to any deviation from expected parameters.
Part 2: The Real-World Problems with EGR on the CM870
After years around these engines, here's what I've observed about the EGR system's weak points.Cooler failure: EGR coolers on the ISX can and do fail. They're subject to extreme thermal cycling, and over time, this stress can cause cracking. When a cooler fails, coolant can enter the exhaust stream or, worse, the intake.
Coolant in the exhaust shows up as white smoke and unexplained coolant loss. Exhaust in the coolant pressurizes the cooling system, leading to overheating and potential head gasket issues. Neither scenario is good, and both are expensive to fix.
Soot buildup: The recirculated exhaust carries particulate matter. That soot deposits in the intake manifold, on the valves, and in the EGR valve itself. Over time, this buildup restricts airflow and can cause the EGR valve to stick or fail to seal properly.
The heat load: The EGR cooler dumps exhaust heat into the engine coolant. That's heat the cooling system has to manage on top of the engine's own thermal load. In a heavy-duty truck already working hard, that additional heat can push cooling systems closer to their limits.
Maintenance burden: EGR systems require maintenance. Valves need cleaning, coolers need inspection, and when they fail, the repair costs are substantial—especially considering the labor involved in accessing these components on a Class 8 truck.
Part 3: What the TruckTok Stage 2 Kit Actually Does
The TruckTok EGR delete plug kit is designed specifically for the CM870 engine. Here's what's included and why each component matters.CNC machined billet aluminum plates: The plates are made from aircraft-grade billet aluminum, CNC milled for precision fit. This isn't cast material with potential porosity or weak spots. Billet aluminum is machined from solid stock, ensuring consistent material properties and exact dimensions.
High-temperature graphite gaskets: The included gaskets are designed to handle the extreme temperatures found in diesel engine applications. Graphite maintains its sealing properties through thermal cycles and won't deteriorate over time like some other materials.
Sealed high-pressure plug fittings: The plugs are designed to seal coolant and exhaust ports with reliability. They're engineered to handle the pressures found in these systems without leaking.
Precision manufacturing: All components are CNC laser cut or CNC machined from high-quality materials. This ensures perfect fit and eliminates the need for modification during installation.
Complete kit: The package includes everything needed for the delete—plates, gaskets, and plugs. No chasing down missing parts or improvising solutions.
Part 4: What You Gain by Removing the EGR System
For trucks that are used off-road or in applications where emissions compliance isn't a factor, EGR deletion offers several real benefits.Cooler intake air: With no hot exhaust gas being recirculated, the air entering the engine is significantly cooler. Cooler air is denser, which means more oxygen for combustion. That translates to more complete burning and better efficiency.
Cleaner intake tract: Without soot-laden exhaust flowing through the intake, carbon buildup is eliminated. The intake manifold, valves, and turbo inlet stay clean, maintaining airflow and performance over the long term.
Reduced cooling system load: The EGR cooler is no longer dumping exhaust heat into the coolant. That means the cooling system can focus entirely on managing engine heat rather than dealing with waste heat from emissions equipment.
Elimination of failure points: The EGR cooler and valve are complex components with moving parts and exposure to extreme conditions. Removing them eliminates the possibility of failure entirely. No cracked cooler, no stuck valve, no coolant in the intake.
Simplified maintenance: With the EGR system gone, there's one less thing to inspect, clean, or repair. For trucks that run hundreds of thousands of miles, that simplification adds up over time.
Part 5: The Material Science – Why It Matters
The product description emphasizes the materials used, and that's not just marketing—it matters for long-term durability.Aircraft-grade billet aluminum: This material is chosen for its strength-to-weight ratio and consistency. Unlike cast aluminum, billet has no porosity or hidden defects. CNC machining ensures precise dimensions and perfect fit.
High-temperature graphite gaskets: Graphite handles extreme temperatures better than traditional gasket materials. It doesn't crack, shrink, or lose sealing pressure over time. For connections that need to remain leak-free for hundreds of thousands of miles, graphite is the right choice.
Precision manufacturing: CNC laser cutting and CNC machining produce components with tolerances that simply aren't possible with less precise methods. This means the plates fit exactly where they need to, with no filing, grinding, or modification required.
Part 6: The Installation Reality
These are heavy-duty trucks with tightly packed engine bays, and accessing the EGR components requires significant disassembly. The kit itself is straightforward once you're in there, but getting to that point takes time and mechanical competence.This is not a driveway job for a beginner. It's work best done by someone familiar with these engines and equipped with the right tools.
The payoff is permanent. Once the EGR system is removed, it's gone. No more worrying about cooler failure, no more carbon buildup, no more EGR-related maintenance.
Part 7: The Tuning Requirement
As with any modern diesel, removing the EGR hardware requires corresponding software changes. The CM870 ECM is programmed to monitor EGR operation—valve position, flow rates, temperatures. When it detects that the system is missing, it'll set codes and may derate power.A proper delete tune is required to:
- Disable EGR monitoring
- Eliminate fault codes
- Optimize fuel delivery for the new airflow characteristics
Part 8: The Verdict
The 2002-2007 Cummins ISX with CM870 ECM is a workhorse engine that powers thousands of heavy trucks across North America. Its EGR system, while effective at reducing NOx emissions, introduces heat, soot, and potential failure points that affect long-term reliability.The TruckTok Stage 2 EGR Delete Plug Kit addresses these issues directly. It replaces the problematic EGR valve and cooler with precision-machined plates and plugs made from aircraft-grade billet aluminum. High-temperature graphite gaskets and quality plug fittings ensure leak-free operation.
For trucks used in off-road applications where emissions compliance isn't required, this kit offers several real benefits:
- Cooler intake air for better combustion
- Cleaner intake tract with no carbon buildup
- Reduced load on the cooling system
- Elimination of EGR-related failure points
- Simplified long-term maintenance
For owner-operators and fleet managers looking to improve the reliability and efficiency of their ISX-powered trucks in off-road applications, this kit represents a permanent solution to a persistent problem.
If you've deleted the EGR on an ISX CM870, what was your experience? Drop your thoughts below.
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