Mercury Quicksilver 865615Q06 Serpentine Belt — MerCruiser V8 5.0L–8.2L Sterndrive
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Mercury Quicksilver 865615Q06 — Serpentine Accessory Drive Belt
| Part Number | 865615Q06 |
|---|---|
| Mercury Reference | 57-865615Q06 |
| SKU | 865615Q06 |
| Brand | Mercury / Quicksilver (OEM) |
| Product Type | Serpentine Accessory Drive Belt |
| System | MerCruiser V8 Sterndrive Accessory Drive |
| Belt Length | 2,667 mm |
| Configuration Requirement | Closed-cooling system with power steering |
| Supersedes | 865615006 / 57-865615006 / 8638766 / 8610491 |
| Aftermarket Cross-Reference | Sierra 18-15102 |
| GTIN | 745061630468 |
| Weight | approx. 450 g |
Overview
Quicksilver 865615Q06 is a genuine Mercury Marine OEM serpentine accessory drive belt measuring 2,667 mm, designed for MerCruiser V8 sterndrive engines with closed cooling and power steering. It drives the alternator, circulating water pump, power steering pump, and other accessories from the crankshaft pulley. On a closed-cooled MerCruiser, belt failure stops coolant circulation immediately — making proactive replacement at scheduled service intervals the right approach rather than waiting for a failure underway.
Fitment note: Multiple belt lengths exist within the MerCruiser 865615 family. The Q06 (2,667 mm) is specifically for closed-cooling engines with power steering. Similar engines without closed cooling, without power steering, or with a different accessory arrangement may use a different belt length. Confirm by checking the part number printed on your existing belt, or by looking up your engine serial number in the Mercury parts catalog.
Supersession & Cross-Reference
- Current part number: 865615Q06 / 57-865615Q06
- Supersedes: 865615006 / 57-865615006
- Supersedes: 8638766 / 57-8638766
- Supersedes: 8610491 / 57-8610491
- Sierra aftermarket equivalent: 18-15102
- If your existing belt or service records show any superseded number above, 865615Q06 is the correct current OEM replacement.
865615 Belt Family — Variant Reference
- 865615Q06 — 2,667 mm — this listing; V8 sterndrive, closed-cool with power steering
- 865615Q10 — 2,195 mm; MerCruiser 5.7L & 6.2L MPI MIE, closed-cool with 4-1/4" idler pulley — verify before substituting
Compatible Applications
- MerCruiser 5.0L V8 sterndrive — closed-cooling (confirm serial range)
- MerCruiser 5.7L / 350 MAG V8 sterndrive — closed-cooling (confirm serial range)
- MerCruiser 350 MAG MPI Alpha/Bravo — closed cooling with power steering (confirm serial range)
- MerCruiser 5.0L MPI Alpha/Bravo — closed cooling with power steering (confirm serial range)
- MerCruiser 377 MAG MPI Alpha/Bravo — closed cooling with power steering (confirm serial range)
- MerCruiser MX 6.2L MPI Alpha/Bravo — closed cooling (confirm serial range)
- MerCruiser 6.2L V8 sterndrive — selected closed-cooling configurations
- MerCruiser 7.4L V8 sterndrive — selected configurations (confirm serial range)
- MerCruiser 8.1L V8 sterndrive/inboard — selected configurations (confirm serial range)
- MerCruiser 8.2L V8 — selected configurations (confirm serial range)
- Configuration requirement: Closed-cooling system with power steering — engines without this arrangement use a different belt length
- Always confirm fitment using your engine serial number and the part number on your existing belt
Service Interval
- Inspect at every 100-hour service or annually, whichever comes first
- Replace immediately if cracking, fraying, glazing, missing ribs, or belt contamination (oil or coolant) is found
- Proactive replacement at scheduled intervals is strongly recommended — belt failure on a closed-cooled engine stops coolant circulation immediately
- Inspect idler pulleys, tensioner pulley, alternator pulley, and circulating pump pulley for wear, wobble, and alignment at every belt replacement
- Confirm the exact service interval for your engine in the Mercury/MerCruiser service manual for your model and serial range
Installation Notes
- Before removing the old belt, photograph the routing or refer to the MerCruiser service diagram for your engine model
- While the belt is off, inspect the tensioner, idler pulleys, alternator pulley, circulating pump pulley, and power steering pump pulley for wear, wobble, bearing roughness, and alignment
- Route the new belt exactly per the MerCruiser diagram — incorrect routing causes immediate belt failure or accessory damage
- Confirm every rib is fully seated in the corresponding pulley groove before running the engine
- After startup, verify the belt tracks correctly on all pulleys with no edge riding, vibration, or squealing
Technical FAQ
- What distinguishes the Q06 from other 865615-series belts? Belt length: 2,667 mm. This is longer than the Q10 (2,195 mm) and is specifically matched to V8 MerCruiser sterndrive engines with closed cooling and power steering. Always confirm by checking the part number on your existing belt or looking up your serial number.
- My belt shows 865615006, 8638766, or 8610491 — is Q06 the right replacement? Yes. All three numbers are superseded by 865615Q06, the current OEM replacement for those applications.
- Can I use the Sierra 18-15102 instead? Sierra 18-15102 is the aftermarket cross-reference for this application. The 865615Q06 is the OEM Quicksilver equivalent. Both reference the same belt specification.
- Should I replace the tensioner or idler pulleys at the same time? If any pulley shows wobble, bearing roughness, or the tensioner arm has lost spring tension, replacing them during the same service visit avoids a return job for a related failure. See the Mercury MerCruiser Serpentine Belt & Pulley Kit 8M0150824.
- My belt squeals after installation — what should I check? Check belt tension first — a worn tensioner spring may not apply adequate load. Then inspect all pulleys for glazing, wobble, or misalignment. A new belt on a worn idler or misaligned pulley will squeal and wear rapidly.
- What happens if the belt breaks underway? On a closed-cooled MerCruiser, belt failure stops the circulating water pump and causes rapid engine overheating. Shut down as quickly as safely possible — do not continue running with a failed serpentine belt on a closed-cooled engine.
Parts Desk Insights
Best Use Case: This belt is the right choice for a scheduled 100-hour or annual service on MerCruiser V8 sterndrive engines with closed cooling and power steering. Because the belt drives the coolant pump on these engines, waiting for a failure on the water is a genuine overheating risk — proactive replacement at every major service is strongly recommended. It’s also the correct current replacement for any engine whose records show 865615006, 8638766, or 8610491.
Common Issues: The most frequent ordering error is selecting a belt by engine displacement alone without confirming the cooling system type and power steering configuration. A 5.7L MerCruiser without closed cooling or power steering may use a different belt length entirely. Always check the existing belt’s part number or the engine serial number before ordering. If the belt squeals shortly after a fresh install, the usual cause is a worn tensioner that isn’t applying enough tension, or a pulley with surface glazing — inspect all pulleys whenever the belt is replaced.
Related Products
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