{"product_id":"volvo-penta-serpentine-belt-tensioner-3860079","title":"Volvo Penta Serpentine Belt Tensioner 3860079 | 4.3L 5.0L 5.7L 7.4L 8.2L OEM","description":"\u003ch2\u003eVolvo Penta Serpentine Belt Tensioner – 3860079\u003c\/h2\u003e\n\n\u003ch3\u003ePart Information\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003ePart Number:\u003c\/strong\u003e 3860079\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eBrand:\u003c\/strong\u003e Volvo Penta\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eOfficial Product Type:\u003c\/strong\u003e Automatic Serpentine Belt Tensioner Assembly\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eOEM Status:\u003c\/strong\u003e Genuine Volvo Penta\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eSupersedes:\u003c\/strong\u003e 872984\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eSystem:\u003c\/strong\u003e Accessory Drive – Serpentine Belt Tensioner\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eWeight:\u003c\/strong\u003e Approx. 0.75 kg (1.65 lb)\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003eWhat This Part Does\u003c\/h3\u003e\n\u003cp\u003eThe 3860079 is the OEM automatic serpentine belt tensioner for selected Volvo Penta gasoline marine engines. It maintains the correct operating tension on the accessory drive belt so the alternator and other belt-driven accessories run reliably without belt slip or over-tension. The spring-loaded tensioner arm and smooth pulley assembly compensate for normal belt stretch and thermal expansion throughout the engine’s operating range.\u003c\/p\u003e\n\n\u003ch3\u003eCompatible Applications\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003eVolvo Penta 4.3GXi \/ 4.3OSi\u003c\/li\u003e\n\u003cli\u003eVolvo Penta 5.0GXi \/ 5.0OSi\u003c\/li\u003e\n\u003cli\u003eVolvo Penta 5.7Gi \/ 5.7GL \/ 5.7Si\u003c\/li\u003e\n\u003cli\u003eVolvo Penta 5.7GXi \/ 5.7GXiI \/ 5.7OSi \/ 5.7OSXi\u003c\/li\u003e\n\u003cli\u003eVolvo Penta 7.4Gi \/ 7.4GSi\u003c\/li\u003e\n\u003cli\u003eVolvo Penta 8.2GSi\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003eFitment spans 4.3L, 5.0L, 5.7L, 7.4L, and 8.2L gasoline engine families. Volvo Penta used several accessory-drive configurations across these families, so confirming by engine model and serial number — not displacement alone — is essential before ordering.\u003c\/p\u003e\n\n\u003ch3\u003eSerial Number Fitment Notice\u003c\/h3\u003e\n\u003cp\u003eLocate the engine data plate for your model and serial number, then confirm against the Volvo Penta accessory-drive or belt-routing diagram that \u003cstrong\u003e3860079\u003c\/strong\u003e (or its predecessor \u003cstrong\u003e872984\u003c\/strong\u003e) is specified for your configuration before ordering.\u003c\/p\u003e\n\n\u003ch3\u003eWhen to Replace\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003eTensioner pulley bearing is noisy, rough, or seized\u003c\/li\u003e\n\u003cli\u003eTensioner arm binds, stutters, or does not move smoothly\u003c\/li\u003e\n\u003cli\u003eBelt tension is weak, inconsistent, or cannot be maintained\u003c\/li\u003e\n\u003cli\u003eSerpentine belt repeatedly slips, squeals, or throws off\u003c\/li\u003e\n\u003cli\u003ePulley shows excessive wobble or play\u003c\/li\u003e\n\u003cli\u003eBelt wear is uneven across its width\u003c\/li\u003e\n\u003cli\u003eSpring-loaded mechanism no longer returns to correct tension\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003eService Interval\u003c\/h3\u003e\n\u003cp\u003eVolvo Penta does not publish a fixed hour-based replacement interval for the belt tensioner. Inspect the tensioner pulley and arm action annually or whenever the serpentine belt is being serviced. Replace if any roughness, binding, or tension loss is found — a failing tensioner will accelerate belt wear and can cause accessory and charging failures.\u003c\/p\u003e\n\n\u003ch3\u003eInstallation Notes\u003c\/h3\u003e\n\u003cp\u003eInspect the serpentine belt, idler pulleys, alternator pulley, and other accessory bearings while the tensioner is being replaced — any worn component in the accessory-drive circuit can accelerate wear on a new tensioner. Release belt tension per the Volvo Penta service procedure for your engine, remove the tensioner, and install the replacement in the same orientation. After fitting the belt, confirm it is fully seated in every grooved pulley and that the tensioner arm moves freely through its full operating range. If the existing belt shows glazing, cracking, fraying, or uneven edge wear, replacing it at the same time is strongly recommended.\u003c\/p\u003e\n\n\u003ch3\u003eTechnical FAQ\u003c\/h3\u003e\n\u003cp\u003e\u003cstrong\u003eQ: Does 3860079 replace 872984?\u003c\/strong\u003e\u003cbr\u003eA: Yes. Volvo Penta 3860079 is the current number and supersedes the earlier 872984.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eQ: Should I replace the serpentine belt at the same time?\u003c\/strong\u003e\u003cbr\u003eA: If the belt shows any wear, glazing, cracking, or age, yes. The belt and tensioner work together — a worn belt can cause a new tensioner to wear faster, and a failing tensioner is often what damages a belt prematurely.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eQ: Can a bad tensioner damage other components?\u003c\/strong\u003e\u003cbr\u003eA: Yes. Insufficient tension causes belt slip and poor alternator output. Excessive wear or a seizing pulley can throw the belt entirely, leaving the engine without cooling and charging.\u003c\/p\u003e\n\n\u003ch3\u003eAlternate Part Numbers\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003eVolvo Penta 3860079\u003c\/li\u003e\n\u003cli\u003e872984 (superseded)\u003c\/li\u003e\n\u003cli\u003eREC3860079\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003eParts Desk Insights\u003c\/h3\u003e\n\u003cp\u003eA worn tensioner is one of the most commonly overlooked causes of a belt going through multiple replacements on the same engine. If a customer is on their second or third serpentine belt and still getting noise or slip, the tensioner pulley bearing or spring action is usually the culprit. When replacing the tensioner, it’s worth checking all the other pulleys in the accessory-drive circuit at the same time — a bad idler pulley or rough alternator bearing will kill a new tensioner just as quickly as a worn one would have killed the old belt.\u003c\/p\u003e","brand":"VOL","offers":[{"title":"Default Title","offer_id":43564033540132,"sku":"3860079","price":319.0,"currency_code":"CAD","in_stock":false}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0743\/5799\/7604\/files\/2da9d802-6d63-4bee-b325-52437d430d7d.png?v=1788843024","url":"https:\/\/marisolmarine.com\/products\/volvo-penta-serpentine-belt-tensioner-3860079","provider":"Marisol Marine Company","version":"1.0","type":"link"}