GM 84379859 Driver Underbody Rear Air Deflector

( Brand: Gm ), ( Manufacturer Part Number: 84379859 ), ( Part Type: Driver Deflector ), ( Genuine Oem: Yes ), ( Manufacturer Warranty: 1 Year ), ( Universal Fitment: Direct Replacement ), ( Make: Buick ), ( Year: 2017 2018 2019 ), ( Parts Included: Only Part Reference 13 On The Diagram Is Included ), ( Replaces Part Number: 26678241, 26687408 )

Review GM Genuine Driver Side Underbody Rear Air Deflector fits LACROSSE 2017–2019

The **GM 84379859 Driver Underbody Rear Air Deflector** is a precision-engineered aftermarket component designed to enhance aerodynamic efficiency and reduce wind noise for General Motors vehicles equipped with the appropriate underbody architecture. Crafted from high-quality, durable materials, this deflector is strategically positioned beneath the driver s side rear quarter panel, where it channels airflow away from critical suspension and brake components while minimizing turbulence. Its sleek, contoured shape ensures a seamless integration with the vehicle s undercarriage, preventing air from swirling around the wheel wells and underbody, which can lead to increased drag and unwanted road noise. Ideal for performance-oriented drivers and those seeking a refined driving experience, this deflector is particularly beneficial for vehicles prone to wind buffeting at highway speeds, such as the Chevrolet Camaro, Corvette, or certain models of the GMC Sierra and Chevrolet Silverado. Constructed to meet rigorous durability standards, it is resistant to corrosion and designed to withstand the rigors of daily driving, including exposure to road debris and varying weather conditions. Whether installed as part of a full underbody aerodynamics package or as a standalone upgrade, the GM 84379859 Driver Underbody Rear Air Deflector delivers a subtle yet impactful improvement in both handling dynamics and acoustic comfort, making it a valuable addition for enthusiasts looking to optimize their vehicle s performance and refinement.

### **Pros and Cons of buying a GM 84379859 Driver Underbody Rear Air Deflector**

1. **Improved Aerodynamics** The deflector helps reduce drag by redirecting airflow around the vehicle s rear, which can slightly enhance fuel efficiency, especially at highway speeds.

2. **Reduced Underbody Wind Noise** It minimizes the whistling and rattling sounds caused by air passing under the vehicle, improving cabin comfort.

3. **Potential Cooling Benefits** By altering airflow, it may help keep the rear brake drums or exhaust components cooler, reducing heat buildup in certain conditions.

4. **OEM Fitment** As a genuine GM part, it is designed to match the vehicle s underbody structure precisely, ensuring proper installation and functionality.

5. **Durability** Made from high-quality materials, it is built to withstand road debris, salt, and general wear over time.

6. **Aesthetic Consistency** Maintains the vehicle s original appearance without requiring aftermarket modifications that may not align with the factory look.

1. **Cost** Being an OEM part, it is more expensive than generic aftermarket alternatives, which may offer similar benefits at a lower price.

2. **Installation Complexity** Requires access to the vehicle s undercarriage, which may involve lifting or jacking the car, potentially requiring professional installation if the buyer lacks mechanical experience.

3. **Limited Availability** Since it is a GM-specific part, sourcing may be difficult if the vehicle is no longer in production or if the part is discontinued.

4. **Minimal Performance Gain** While it improves aerodynamics slightly, the impact on fuel economy may not be significant enough to justify the cost for some drivers.

5. **Potential for Damage** If installed incorrectly or if the vehicle is driven off-road or in rough conditions, the deflector could become damaged or dislodged.

6. **Weight Addition** The deflector adds slight extra weight to the rear of the vehicle, which may have a negligible but measurable effect on handling dynamics.

The GM 84379859 driver underbody rear air deflector is a well-engineered component that offers tangible benefits in terms of noise reduction, aerodynamics, and cooling. Its OEM quality ensures reliability and proper fitment, making it a solid choice for those who prioritize original equipment standards and long-term durability. However, the higher cost and installation challenges may deter some buyers, particularly if they are seeking a more budget-friendly or easier-to-install alternative.

For drivers who experience significant underbody wind noise, seek improved rear cooling, or want to maintain their vehicle s factory appearance, this part is a worthwhile investment. Conversely, those on a tight budget or those who can tolerate minor wind noise may find aftermarket options more practical.

If you own a GM vehicle and are experiencing underbody wind noise or seeking subtle aerodynamic improvements, purchasing the **GM 84379859 driver underbody rear air deflector** is a sound decision. Ensure you have the necessary tools or professional assistance for installation, and verify compatibility with your specific vehicle model and year. If cost is a concern, compare it with high-quality aftermarket alternatives that offer similar benefits before making a final decision.

Details:

Changed My Mind. Found a Better Price. Just Didn't Like it.

part #: 84379859 prices

• $8.56-$30.24

specifications ocoosys:

• for models: Lacrosse
• for years: 2017-2019
• brand: Gm
• mpn: 84379859
• part type: Driver Deflector
• genuine oem: Yes
• manufacturer warranty: 1 Year
• universal fitment: Direct Replacement
• make: Buick
• year: 2017 2018 2019
• parts included: Only Part Reference 13 On The Diagram Is Included
• replaces part number: 26678241, 26687408

shipping ocoosys:

• transit: 5-11 Days
• class: Standard
• cost: $0.00
• type: Fixed
• carrier: FedEx
• service: FedEx Ground / FedEx Home Delivery

general ocoosys:

• condition: New
• Car Truck Parts Accessories > Engine Cooling Components > Other Engine Cooling Components

payments ocoosys:

• credit card: Diners-club
• wallet: Google-pay
• other

seller ocoosys:

• # reviews: 30897
• city: Garland, Texas
• rating: 99.0%

offer ocoosys:

• sold: 0
• options: Ship-to-home
• started: April 13, 2026
• availability: In Stock
• quantity: 4

returns ocoosys:

• time: 30 Days
• paid by: Seller
• policy: Returns Accepted

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