1983 Chevrolet Impala Emission Components
Standard Motor Products EF1 Early Fuel Evaporation (EFE) Heater Assembly
What Are Emission Components?
Modern diesel engines rely on a sophisticated network of emission control components to meet increasingly strict environmental regulations. At the heart of this system is Selective Catalytic Reduction (SCR) technology — an exhaust aftertreatment process that dramatically reduces harmful pollutants before they ever leave the tailpipe. Emission components are the hardware that makes this process possible, and keeping them in proper working order is essential for both legal compliance and engine health.
The SCR system works by using Diesel Exhaust Fluid (DEF) — stored in a dedicated DEF tank — and injecting it into the hot exhaust stream upstream of the SCR catalyst. Once there, DEF breaks down into ammonia and carbon dioxide, and the ammonia reacts with nitrogen oxides (NOx) in the exhaust to produce harmless nitrogen gas and water vapor. Every component in this chain — from the tank and heater to the pump and injection nozzle — must function correctly for the system to reduce emissions effectively.
Why Emission Component Maintenance Matters
A failure anywhere in the DEF delivery system can trigger fault codes, cause engine derating, and in some cases prevent the vehicle from restarting altogether. Because DEF freezes at around 12°F, DEF heaters are critical for cold-climate operation, thawing the fluid so it can flow freely to the injector. The DEF pump maintains consistent fluid pressure and flow from the tank to the DEF injection nozzle, which atomizes the fluid into the exhaust stream for the most effective chemical reaction. Even a small component like the DEF filler cap plays a role — a degraded or missing cap can allow contamination that damages the entire SCR system.
Whether you’re maintaining a light-duty pickup, a Class 8 semi-truck, or a piece of heavy equipment, sourcing quality replacement emission components is the difference between a smooth repair and a recurring headache.
Top Brands in Emission Components
ACDelco is a trusted OEM-level supplier with a broad catalog of DEF system components covering most GM applications and many non-GM diesel vehicles. ACDelco parts are engineered to meet GM Original Equipment specifications and API/ISO 22241 purity and performance standards.
Bosch is widely recognized as the world’s leading OE supplier of diesel fuel systems, and their emission components carry the same exacting standards as their original equipment parts. Bosch aftermarket DEF components are designed for direct OE-replacement performance across a wide range of commercial and passenger diesel applications.
Dorman offers the widest catalog selection in this category, with over 40 emission component SKUs. Dorman is known for their OE FIX solutions, which often improve upon original designs to address known failure points — particularly useful for high-mileage trucks prone to DEF system issues.
Spectra Premium specializes in direct-fit DEF system components, including pumps designed to ensure consistent DEF transfer from tank to injector. Their parts are engineered as plug-and-play replacements for a straightforward repair experience.
Motorad rounds out the category with a focused line of DEF components, offering reliable replacement options for targeted applications where a precise OE-style fit is required.
Shop by Subcategory
- Diesel Exhaust Fluid (DEF) Tank – The reservoir that stores DEF fluid onboard the vehicle, sized and shaped to match OE specifications for each application.
- Diesel Exhaust Fluid (DEF) Heater – Prevents DEF from freezing in cold temperatures, ensuring year-round SCR system operation.
- Diesel Exhaust Fluid (DEF) Injection Nozzle – Atomizes and delivers DEF into the exhaust stream upstream of the SCR catalyst for maximum NOx conversion efficiency.
- Diesel Exhaust Fluid (DEF) Pump – Draws DEF from the tank and supplies consistent pressure to the injection nozzle throughout engine operation.
- Diesel Exhaust Fluid (DEF) Filler Cap – Seals the DEF tank to prevent contamination, evaporation, and spillage that could compromise the SCR system.