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2004–2005 Silverado & Sierra 6.6L Duramax LLY Cold Air Intake
Built for the 2004–2005 6.6L Duramax LLY trucks listed below, this Flashark cold air intake replaces the factory airbox, filter, and intake tubing with a heat-shielded intake assembly. Its dry, washable filter and aluminum intake tube give LLY Duramax owners a serviceable intake setup for towing, daily driving, or a broader airflow build.
Specifications
| Brand | Flashark |
|---|---|
| SKU | FLIS08759 |
| Product type | Cold Air Intake Kit; heat-shielded, open-element configuration |
| Tube | Aluminum intake piping |
| Filter | Red dry cotton filter; washable and reusable; do not apply filter oil |
| Finish | Black intake tube / red filter |
| Factory MAF | Reuses the factory mass airflow sensor; no spacer or adapter is required |
| Installation | Uses factory mounting points; no cutting or drilling; approximately 45–60 minutes with basic hand tools |
Key Features
- Complete intake replacement: Replaces the factory airbox, paper filter, and intake tubing with a filter, intake tube, and heat shield assembly.
- Dry washable filter: The reusable dry cotton filter is designed to be cleaned without filter oil, helping avoid an over-oiling step near the MAF sensor.
- Aluminum intake tube: The mandrel-bent aluminum tube replaces the factory corrugated rubber hose in the intake path ahead of the turbo inlet.
- Stamped-steel heat shield: The included shield separates the filter from surrounding engine-bay components.
- Factory MAF transfer: Reuses the original MAF sensor without a spacer or adapter when installed in the correct direction and with all connections sealed.
- Bolt-on mounting: Uses factory mounting points and is designed for installation without cutting or drilling.
- Expected intake-only output range: Approximately 7–10% horsepower and 6–8% torque; results vary with vehicle condition, calibration, installation, exhaust, elevation, temperature, and load.
- More present turbo sound: The open-element filter and intake tube make the turbo whistle more noticeable under acceleration; sound is subjective.
- All-season materials: Aluminum piping, a dry filter, and a steel heat shield are configured for the engine-bay environment.
Who This Kit Is For
This kit is for 2004–2005 Chevrolet Silverado 2500HD/3500 and GMC Sierra 2500HD/3500 trucks with the 6.6L Duramax LLY turbo-diesel engine.
- For you if: You have confirmed the LLY engine code and want a reusable dry-filter intake for a stock or modified truck.
- For you if: You want to replace the factory airbox and corrugated intake hose while retaining the factory MAF sensor.
- For you if: You are comparing compatible applications in the Silverado and Sierra cold air intake collection.
- Not for you if: Your truck has the 2001–2003 LB7 or 2006–2007 LBZ engine configuration.
- Not for you if: You need a 50-state-legal intake and do not have product-level EO confirmation for your application.
Check Before Ordering
- Confirm the engine code: A 2004 truck must be the LLY configuration; model year alone does not identify every Duramax intake layout.
- Match the exact application: This kit is exact-fit only for the 2004–2005 Silverado/Sierra 2500HD/3500 6.6L Duramax LLY applications shown above. Contact support before ordering if your truck is not listed.
- Verify the MAF transfer: Move the factory sensor to the new tube in the correct airflow direction, confirm its seal, and tighten each coupler and clamp.
- Plan for dry-filter service: Inspect the filter regularly; dusty, farm, construction-site, or off-road use calls for more frequent cleaning. Do not oil the dry filter.
- Check emissions requirements: Confirm the rules that apply where the vehicle will be registered or used before purchase.
- Consider your water exposure: Normal rain and snow use are different from deep-water crossings. Avoid deep water, pressure-washing the exposed filter, or operating with a soaked filter because water ingestion can severely damage a diesel engine.
Browse other compatible platform options in the Chevrolet and GMC cold air intake collection.
What's in the Box
Everything included with this kit is listed below.
- ✓ High-flow red dry cotton air filter
- ✓ Aluminum intake tube
- ✓ Stamped-steel heat shield
- ✓ Silicone couplers, trim tubing, clamps, mounting brackets, and hardware
The original MAF sensor is transferred from the factory intake. Basic hand tools are needed for installation.
Shipping & Returns
Free U.S. Shipping: Orders are typically processed within 1–2 business days and delivered within 7–9 business days. Additional charges may apply to remote areas.
30-Day Returns: Unopened and unused items in their original packaging may be returned within 30 days of receipt. Return shipping is covered for verified quality issues.
Worry-Free Delivery: Optional protection against eligible loss, theft, delay, or transit damage is available at checkout.
Confirmed compatible — 2004–2005 Chevy Silverado & GMC Sierra 2500HD/3500 6.6L Duramax LLY (all trims):
| Year | Make | Model | Engine |
|---|---|---|---|
| 2004 | Chevrolet | Silverado 2500HD | 6.6L V8 Duramax LLY Turbo Diesel |
| 2004 | Chevrolet | Silverado 3500 | 6.6L V8 Duramax LLY Turbo Diesel |
| 2004 | GMC | Sierra 2500HD | 6.6L V8 Duramax LLY Turbo Diesel |
| 2004 | GMC | Sierra 3500 | 6.6L V8 Duramax LLY Turbo Diesel |
| 2005 | Chevrolet | Silverado 2500HD | 6.6L V8 Duramax LLY Turbo Diesel |
| 2005 | Chevrolet | Silverado 3500 | 6.6L V8 Duramax LLY Turbo Diesel |
| 2005 | GMC | Sierra 2500HD | 6.6L V8 Duramax LLY Turbo Diesel |
| 2005 | GMC | Sierra 3500 | 6.6L V8 Duramax LLY Turbo Diesel |
Does NOT fit:
- 2001–2003 Chevy Silverado / GMC Sierra 2500HD/3500 6.6L Duramax LB7 — first-generation Duramax with different intake routing and turbo housing (GT3782VA)
- 2006–2007 Chevy Silverado / GMC Sierra 2500HD/3500 6.6L Duramax LBZ — revised intake manifold, different MAF sensor housing, and Garrett GT3788VRA turbo inlet geometry
2004–2005 6.6L Duramax LLY Cold Air Intake FAQs
Q1: Is this cold air intake legal in my state?
A1: Not legal for sale or use in California (and other CARB-adopting states). Confirm the emissions requirements that apply where the vehicle will be registered or used before ordering.
Q2: Will this fit my 2004 or 2005 Silverado or Sierra?
A2: It is exact-fit for the listed 2004–2005 Chevrolet Silverado 2500HD/3500 and GMC Sierra 2500HD/3500 trucks with the 6.6L Duramax LLY turbo-diesel engine. Verify the LLY engine code before ordering; it does not fit the 2001–2003 LB7 or 2006–2007 LBZ configurations.
Q3: How much horsepower will this add?
A3: Typical intake-only gains for this application are approximately 7–10% horsepower and 6–8% torque. Actual results depend on the vehicle, calibration, installation, exhaust, elevation, temperature, load, and supporting hardware.
Q4: Will a cold air intake improve my MPG?
A4: MPG is dominated by driving habits; an intake alone can't guarantee a measurable gain. Expect the main benefit as throttle response and intake tone rather than fuel economy.
Q5: Will this void my warranty?
A5: Under the Magnuson-Moss Warranty Act, an aftermarket part cannot void your factory warranty unless it is proven to have caused the failure. This kit is designed as a direct bolt-on replacement that keeps factory sensors and connections.
Q6: Will it throw a check engine light (CEL)?
A6: This kit is designed to reuse the factory MAF sensor. Warning lights can result from an intake leak, a reversed or disconnected MAF sensor, damaged wiring, or a loose clamp, so verify the sensor direction and every connection after installation.
Q7: Do I need a tune after installing?
A7: No tune is required for a bolt-on install that retains the factory sensors. A truck with other airflow or fueling modifications may have separate tuning needs, so confirm the full build before making calibration changes.
Q8: Is this safe in rain or deep water?
A8: Normal rain and snow use are acceptable when the intake and heat shield are correctly installed. Avoid deep-water crossings, pressure-washing the exposed filter, or operating with a soaked filter because water ingestion can cause hydrolock and severe engine damage.
Q9: How do I clean the dry filter?
A9: Inspect the filter regularly and clean it when dirt loads the pleats or airflow becomes restricted. Wash it as needed, allow it to dry completely before reinstalling, and do not apply filter oil; dusty or off-road use requires more frequent service.
Q10: What does it sound like?
A10: You may hear a more noticeable turbo whistle and intake sound under acceleration. Sound is subjective and will vary with engine load, exhaust configuration, and the rest of the truck's setup.
Q11: What's included and what do I still need?
A11: The kit includes the dry filter, aluminum intake tube, stamped-steel heat shield, couplers, clamps, brackets, and hardware. Transfer the original MAF sensor and use basic hand tools for installation.
Q12: Will it work with an aftermarket turbo mouthpiece, exhaust, or tune?
A12: This kit is intended as an airbox, filter, and intake-tube upgrade ahead of the turbo inlet. Verify coupler size and component compatibility with support before combining it with an aftermarket turbo mouthpiece; exhaust and tuning changes should be evaluated as part of the complete build.
Fast Shipping Policy
Your order will be dispatched within 1-2 business days, and the package will arrive within your order's estimated date. Click for Shipping Policy
Easy Return Policy
Every order comes with a 30-day free return, provided the item is brand new, uninstalled, and in its original packaging. We cover return shipping for quality issues. Refunds are processed within 3-5 business days. Click for Return Policy
Worry-Free Delivery Protection
Add Worry-Free Delivery at checkout — if it's lost, stolen, or damaged, you're 100% covered. Click for Worry-Free Delivery Protection