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Bosch 9657 - Spark Plug
Product Overview
The Bosch Iridium Spark Plug (MPN: 9657) is engineered to meet OEM standards, ensuring optimal performance for your Mercedes-Benz. As a critical component of your engine, the spark plug ignites the air-fuel mixture, driving the piston and converting this energy into horsepower. With Bosch's premium-grade construction, this spark plug is designed for durability and longevity, outperforming traditional copper plugs. Iridium spark plugs can last up to 60,000 miles, significantly reducing the frequency of replacements compared to standard copper plugs, which typically require changing every 10,000 to 30,000 miles. Choose Bosch 9657 for dependable performance and peace of mind every time you service your vehicle.
Cross Reference Numbers
This Bosch 9657 is equivalent to or replaces the following part numbers: AJTT-18-110, AJTT18110, AGSF-32Y-RA, AGSF32YRA.
Vehicle Compatibility
- Mercedes-Benz 190E 2.3 (1990–1993)
- Mercedes-Benz 190E 2.6 (1990–1993)
- Mercedes-Benz 300E 2.6 (1990–1993)
- Mercedes-Benz 300E 3.0 (1990–1993)
- Mercedes-Benz 300TE 3.0 (1990–1993)
- Mercedes-Benz 300SE 3.0 (1990–1993)
- Mercedes-Benz 300SEL 3.0 (1990–1993)
- Mercedes-Benz 300CE 3.0 (1989–1993)
- Mercedes-Benz 260E 2.6 (1988–1989)
- Mercedes-Benz 300TE 4Matic 3.0 (1990–1993)
This may also fit other applications. Please use the vehicle selector tool to verify fitment.
Why Shop at eEuroparts.com?
- Proven Expertise: Over 25 years of experience with European vehicles means we know your car inside and out.
- Exclusive Kits That Fitâ„¢ - complete repair solutions with no guesswork
- Fitment Confidence: Our accurate cataloging ensures you get the right part the first time.
- Fast, Reliable Shipping: Orders ship quickly from our U.S.-based warehouses.
- Transparent Pricing: Competitive prices with no hidden fees or surprise charges.
- Established Trust: Serving the European auto community since 2000.
Frequently Asked Questions
What does the Bosch 9657 Spark Plug do?
The spark plug ignites the air-fuel mixture in the engine, enabling combustion that powers the vehicle. A properly functioning spark plug ensures efficient engine operation, enhancing performance and fuel efficiency.
How do I know if my Spark Plug needs replacement?
Key signs that your spark plugs may need replacement include engine misfires, rough idling, poor acceleration, and difficulty starting the engine. Regular inspection and timely replacement can prevent more severe engine issues.
Can I install the Bosch 9657 myself?
Yes, you can install the Bosch 9657 spark plug yourself if you have basic mechanical skills. Ensure the engine is cool and follow the manufacturer's instructions for proper installation.
What are the symptoms of a faulty Spark Plug?
Symptoms of a faulty spark plug may include engine misfires, decreased fuel efficiency, rough engine performance, and starting difficulties. If you experience these issues, consider inspecting your Bosch 9657 spark plug for wear or damage.
Why should I choose Bosch for my Spark Plug needs?
Choosing Bosch ensures you receive a high-quality, reliable product trusted by professionals and enthusiasts alike. Order Bosch 9657 today for a factory-correct replacement that restores safety and performance.
Note: All information on this page and in the FAQ is for general reference only. Verify fitment and consult a professional as needed. eEuroparts.com is not responsible for incorrect part selection or installation.
- BrandBosch
- ManufacturerBosch
- MPN9657
- Part TypeSpark Plug
- OE Part NumbersAJTT-18-110, AJTT18110, AGSF-32Y-RA, AGSF32YRA
- Cross Reference NumbersHR 8 DII 33 X, HR8DII33X, 0 242 230 524, 0242230524
- FeaturesCenter Electrode Design : Fine Wire
Electrical Terminal Type : Non-Removable Nut
Ground Configuration : Standard
Ground Electrode Core Material : N/A
Ground Electrode Quantity : 1
Ground Electrode Tip Design : Tapered
Hex Size : 16
Hex Type : Hex
Indexed : No
Insulator Material : Ceramic
Insulator Type : Non-Projected
Manufacturer Heat Range : 8
Outdoor Power Equipment Application : No
Package Contents : Spark Plug
Package Quantity : 1
Pre-Gap Size : 1.1
Product Length : 2.968504 in
Product Width : 0.712598 in
Prop 65 Warning Label Required? : No
Reach : 17.5
Resistance : 6000
Resistor : Yes
Resistor Type : Yes
Seat Type : Tapered
Short Style : No
Spark Plug Type : 4-Cycle
Thread Diameter : 14
- Fitment
- Fitment TypeVehicle Specific
| Year | Make | Model | Submodel |
|---|
Warranty Overview
At eEuroparts, we stand behind the quality of the products we sell. Every part we offer is backed by a warranty designed to give you peace of mind and protect your investment.
Standard Warranty – Most Parts
Coverage: 2 years or 24,000 miles (whichever comes first) from purchase date.
Protection: Defects in materials or workmanship under normal personal use.
Eligibility: Applies only to the original purchaser and the vehicle where the part was first installed.
Exclusions:
Wear-and-tear items (brake pads, filters, bulbs, wipers, etc.)
Commercial, fleet, rideshare, off-road, or racing use
Improper installation, misuse, accidents, or modifications
Not Covered: Labor, shipping, towing, or incidental costs.
Bison Performance Warranty – Our House Brand
Coverage: Limited Lifetime Warranty for as long as you own your vehicle.
Applies To: All products sold under the Bison Performance label.
Premium Protection: Goes beyond our standard warranty — if it’s a Bison product, the 2-year/24k mile limit is replaced with lifetime coverage.
Exclusions: Same as the standard warranty (normal wear, commercial use, improper installation, etc.).
What’s Included: Replacement of the defective product (labor and shipping excluded).
Warranty Claim Requirements
To keep claims fast and fair, we require:
Proof of purchase (invoice or order confirmation).
Photos or videos showing the defective part, order number, date, VIN, and odometer reading.
Diagnostic reports or part returns for non-visible issues may be requested.
Claims must be truthful, properly documented, and reflect normal consumer use.
Buy With Confidence: We back our products because we believe in their quality, with a transparent, customer-first warranty process you can trust. And with Bison Performance products, you’ll enjoy Limited Lifetime protection—an assurance few brands can match.
For full details and exclusions, please see our complete Warranty Terms & Conditions.
This summary is for convenience only. For full warranty coverage details, exclusions, and requirements, see our official Warranty Terms & Conditions. In case of conflict, the full policy governs.
Return Policy Overview
Most parts can be returned within 30 days of delivery if unused, uninstalled, and in original packaging.
To start a return, contact customer support via Chat or Contact Us.
Restocking fee: Up to 20% may apply for certain orders (buyer’s remorse, order errors, or special-order items)
Refunds: Issued to your original payment method within 3–5 business days after inspection
Exchanges: Not automatic — please return and reorder
Replacements: May be approved for incorrect or defective items reported within 7 days
Not returnable:
Used or installed parts
Electrical components
Opened filter kits, gaskets, or contaminated items
Final sale or custom orders
Important Notes:
Return shipping is your responsibility unless we made a verified error
Fitment is the customer’s responsibility (we can assist, but do not guarantee)
Country of origin may vary and is not grounds for return
For complete details, please see our full Return Policy.
This Returns summary is provided for convenience only. All returns, refunds, and exchanges are subject to the complete Returns Policy. In the event of any conflict, the full policy governs.
Fast, Reliable Shipping — Straight to Your Door
We ship most orders the same day when placed before 2 PM CST (Monday–Friday). Our main warehouse is just east of Nashville, TN, and we also ship from multiple locations nationwide to get your order to you as quickly as possible.
We use trusted carriers like UPS, FedEx, and USPS.
Tracking info is emailed to you as soon as your order ships.
Delivery estimates at checkout are based on carrier data, but not guaranteed.
Need help with a shipment?
If your order is missing, damaged, or incorrect, just let us know within 5 days of delivery. We’ll walk you through the quick claim process — including a few photos to help us make things right.
For complete details, please see our full Shipping Policy.
This Shipping summary is provided for convenience only. Delivery times, carrier terms, fees, restrictions, risk of loss, and other details are governed by our complete Shipping Policy. In the event of any conflict, the full policy governs.










