Serpentine Belt Idler Pulley 3861009 for Volvo Penta 3.0L 4.3L 5.0L 5.7L 8.1L V6 V8 DPX
Serpentine Belt Idler Pulley 3861009 for Volvo Penta 3.0L 4.3L 5.0L 5.7L 8.1L V6 V8 DPX
Product Overview
Serpentine belt idler pulley for Volvo Penta 3.0L, 4.3L, 5.0L, 5.7L and 8.1L V6 and V8 sterndrive engines, plus the DPX375 and DPX420 drives. It is a direct replacement for OE 3861009, a 90 mm outer diameter steel and composite pulley carrying a 17.2 mm bore. The idler sets the belt wrap and tension on the serpentine system, so when its bearing dries out the belt starts to chirp cold, then squeals, then walks off the pulley and leaves the engine without a raw water pump or alternator. Replacing the idler rather than re-tensioning the belt is what actually stops the noise.
Specifications & Attributes
| Specification | Detail |
|---|---|
| Condition | New / New with tags |
| Type | Serpentine Belt Idler Pulley |
| Outer Diameter | 90 mm (3.54 in) |
| Inner Diameter | 17.2 mm (0.68 in) |
| Material | Steel / composite (OE grade) |
| Engine Type | Volvo Penta sterndrive, V6 and V8 |
| Displacement | 3.0 L, 4.3 L, 5.0 L, 5.7 L, 8L/8.1 L |
| Country of Origin | Taiwan |
| Packaging | 14.5 x 8.5 x 10.5 cm (5.7 x 3.3 x 4.1 in) |
OEM Cross Reference
| Brand | OEM Part Numbers |
|---|---|
| Volvo Penta | 3861009 |
Compatible Engines
| Displacement | Volvo Penta Model Designations |
|---|---|
| 3.0 L | 3.0GLM-C; 3.0GLP-C, 3.0GLP-D, 3.0GLP-E, 3.0GLP-J, 3.0GLP-N; 3.0GXiC-J; 3.0GXi-J |
| 4.3 L | 4.3; 4.3GL-A to 4.3GL-P; 4.3GXi-A to 4.3GXi-G; 4.3OSi-C to 4.3OSi-J; 4.3GXiE |
| 5.0 L | 5.0GL-A to 5.0GL-J; 5.0GXi-B to 5.0GXi-G; 5.0OSi-A to 5.0OSi-J; 5.0GXi |
| 5.7 L | 5.7G; 5.7Gi-B to 5.7Gi-G; 5.7GXi-C to 5.7GXi-H; 5.7OSi-A to 5.7OSi-G; 5.7OSXi-A to 5.7OSXi-G; 5.7Gi |
| 8.1 L | 8.1; 8.1Gi-A to 8.1Gi-H; 8.1GXi-A to 8.1GXi-H; 8.1OSi-A to 8.1OSi-D; 8.1Gi, 8.1GiE |
| DPX | DPX375-A, DPX375-B, DPX375-C to DPX375-F; DPX420-A, DPX420-B, DPX420-C to DPX420-F |
| V6 / V8 | V6-225-E-A; V8-350 to V8-430 CE/OSXi |
Note: model designations are the manufacturer's own codes. Year information is not published for every designation — verify your engine serial number before ordering.
What's Included
| Component | Qty |
|---|---|
| Serpentine Belt Idler Pulley | 1 |
Condition & Warranty
| Item | Detail |
|---|---|
| Condition | New / New with tags |
| Warranty | Standard |
| Packaging | Sealed retail packaging |
Before You Buy
- Verify your engine model designation or serial number before ordering — Volvo Penta changed the accessory drive across the 3.0 L to 8.1 L range
- Spin the old idler by hand first: rough or dry bearings are the usual source of a cold-start belt chirp
- Inspect the serpentine belt for glazing and cracks and renew it at the same time — a worn belt wears out a new idler
- Torque the mounting bolt to spec and check belt alignment after fitting; a pulley that sits off-plane will throw the belt
- 30-Day Easy Returns
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- OEM Quality Without the Markup
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