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Denso 4085 Spark Plug
| Brand | Denso 4085 |
|---|---|
| Center Electrode Core Material | Copper |
| Center Electrode Tip Material | Nickel |
| Ground Configuration | Standard |
| Ground Electrode Core Material | Nickel |
| Ground Electrode Quantity | 1 |
| Ground Electrode Tip Design | U-Groove |
| Hex Size | 18.0 |
| Manufacturer Heat Range | 22 |
| Pre-Gap Size | 0.9 |
| Reach | 19.00 |
| Seat Type | Flat |
| Thread Diameter | 12.00 |
| Product line | U-Groove Conventional |
| Fits | Kawasaki, Suzuki, BMW, and Yamaha · 7 vehicles |
U-Groove design. Improves ignitability for more efficient engine performance.
Nickel and copper construction. Balances durability with reliable spark delivery.
Spark plug. A standard secondary ignition component for dependable combustion.
Cross-references BMW 12 12 1 311 928, BMW 12 12 9 061 882 and DENSO Auto Parts X22EP-U9 for the same application. See all 3.
Denso 4085 Spark Plug for BMW M3, M5, M6
The Denso 4085 is a conventional spark plug built for BMW secondary ignition applications that call for precise firing and stable combustion. Its U-Groove ground electrode design improves ignitability to support more efficient engine operation in the specified BMW M3, M5, and M6 fitments.
Key Features
- U-Groove ground electrode tip design for improved spark exposure
- Conventional spark plug construction for OE-style service replacement
- Copper center electrode core material for dependable conductivity
- Nickel center electrode tip and ground electrode materials
- 0.9 pre-gap size for the listed applications
- Flat seat design with 12.00 mm thread diameter and 19.00 reach
- 18.0 hex size for proper socket fitment
- Manufacturer heat range 22
Product Details
Denso U-Groove Conventional spark plugs are engineered around a ground electrode shape that exposes more of the spark kernel, helping the plug fire cleanly in demanding ignition systems. Part number 4085 is specified for 1988-1991 BMW M3, 1988 BMW M5, and 1987-1988 BMW M6 applications, making it a direct-fit choice for owners servicing these classic BMW performance models. This part cross-references DENSO Auto Parts X22EP-U9 for the same application.
Common Issues This Spark Plug Can Address
- Hard starting caused by worn or inefficient spark plugs
- Rough idle from inconsistent ignition performance
- Misfire conditions related to degraded plug electrodes
- Reduced combustion efficiency from excessive plug wear
- Service replacement needs on BMW M3, M5, and M6 ignition systems
Installation Notes and Tips
Verify the thread diameter, reach, seat type, and pre-gap before installation to match the engine specification. Use the correct 18.0 mm hex socket and follow the vehicle service manual for torque and gap verification. For BMW M3, BMW M5, and BMW M6 applications, confirm the engine code and existing plug specification before final installation.
Quality Assurance
Denso manufactures this spark plug as part of its U-Groove Conventional line, using a copper core and nickel electrode materials for consistent ignition service in the listed BMW applications. Part number 4085 is built to the stated OE-style dimensions and fitment requirements for the vehicles shown.
| Year | Make | Model | Position | Notes |
|---|---|---|---|---|
| 1991 | BMW | M3 | N/A | U-Groove Conventional |
| 1990 | BMW | M3 | N/A | U-Groove Conventional |
| 1989 | BMW | M3 | N/A | U-Groove Conventional |
| 1988 | BMW | M3 | N/A | U-Groove Conventional |
| 1988 | BMW | M5 | N/A | U-Groove Conventional |
| 1988 | BMW | M6 | N/A | U-Groove Conventional |
| 1987 | BMW | M6 | N/A | U-Groove Conventional |
| No rows match your filter. | ||||