{"product_id":"seasierra-thermostat-kit-for-omc-cobra-volvo-penta-4-3-5-8l-160-f-small-volvo-style","title":"SeaSierra Thermostat Kit for OMC Cobra \u0026 Volvo Penta 4.3–5.8L — 160°F Small Volvo‑Style","description":"\u003cp\u003e\u003cstrong\u003eSeaSierra 383307 Thermostat Kit is a direct-fit replacement thermostat assembly designed for OMC Cobra and Volvo Penta engine drives on 4.3L, 5.0L, 5.7L and 5.8L Ford- and GM‑based V6\/V8 marine engines.\u003c\/strong\u003e\u003c\/p\u003e\n\n\u003cp\u003eThis kit supplies the small-size thermostat used by many OMC Cobra and Volvo Penta lower units, with a 160°F (71°C) temperature rating. It replaces several OEM and aftermarket part numbers, and is intended as a maintenance or repair component for cooling systems that require the smaller Volvo-style thermostat. Before installing, check your existing thermostat style and part number to ensure this kit matches your drive assembly.\u003c\/p\u003e\n\n\u003ch3\u003eWhich engines and drives will accept this thermostat kit?\u003c\/h3\u003e\n\u003cp\u003eThe SeaSierra 383307 fits most 4.3L, 5.0L, 5.7L and 5.8L engines built from Ford and General Motors V6 and V8 platforms when used with compatible OMC Cobra and Volvo Penta lower units. It is especially common on setups where the smaller Volvo thermostat was originally installed.\u003c\/p\u003e\n\u003cul\u003e\n  \u003cli\u003eCompatible with OMC Cobra and Volvo Penta engine drives\u003c\/li\u003e\n  \u003cli\u003eSuitable for many Ford- and GM-based 4.3L–5.8L V6\/V8 marine engines\u003c\/li\u003e\n  \u003cli\u003eDesigned as the smaller Volvo-style thermostat element\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003eWhat temperature does this thermostat open at and why that matters?\u003c\/h3\u003e\n\u003cp\u003eThis thermostat has a rated opening temperature of 160°F (71°C). That temperature helps the engine reach and maintain its designed operating range, balancing warm-up speed with cooling control to protect internal components from overheating under load.\u003c\/p\u003e\n\u003cul\u003e\n  \u003cli\u003eRated at 160°F \/ 71°C for consistent thermal control\u003c\/li\u003e\n  \u003cli\u003eHelps stabilize engine operating temperature under varying loads\u003c\/li\u003e\n  \u003cli\u003eManufactured to match common OEM thermostatic characteristics\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003eWhich part numbers does this SeaSierra kit replace, and how to confirm fit?\u003c\/h3\u003e\n\u003cp\u003eThis kit can substitute for several OEM and aftermarket identifiers, but fit should be confirmed visually and by part number. The listing replaces numbers like 383307, 3856961, 778056, 307239, 312797 and Sierra 18-3677, though Volvo and OMC sometimes used different sizes.\u003c\/p\u003e\n\u003cul\u003e\n  \u003cli\u003eReplaces: 383307, 3856961, 778056, 307239, 312797, Sierra 18-3677\u003c\/li\u003e\n  \u003cli\u003eCompare your existing thermostat dimensions and shape before ordering\u003c\/li\u003e\n  \u003cli\u003eContact SeaSierra or your mechanic if your drive previously used the larger Volvo thermostat\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003eHow should I check compatibility before installation?\u003c\/h3\u003e\n\u003cp\u003eInspect the thermostat you are removing and compare its shape, overall diameter, and mounting style to this kit. Volvo used two different thermostat sizes in some years; this SeaSierra kit is the smaller version, so double-check to avoid ordering the wrong size.\u003c\/p\u003e\n\u003cul\u003e\n  \u003cli\u003eRemove and photograph your current thermostat for comparison\u003c\/li\u003e\n  \u003cli\u003eVerify stamped part numbers or measurements against this kit\u003c\/li\u003e\n  \u003cli\u003eReach out to SeaSierra support with vehicle and drive details if unsure\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003cp\u003eWho this is for: This kit is intended for boat owners, marine technicians and DIY mechanics who need a reliable, small-size replacement thermostat for OMC Cobra or Volvo Penta lower units on 4.3L–5.8L Ford- or GM-derived V6\/V8 engines. If you operate a vessel with the smaller Volvo thermostat style and require a 160°F (71°C) replacement or a direct substitute for the listed part numbers, this SeaSierra thermostat kit offers a cost-effective maintenance option. If your drive used the larger Volvo thermostat or you cannot confirm the existing part, consult your service manual or contact SeaSierra before purchasing to ensure correct fitment.\u003c\/p\u003e\n\u003csection class=\"product-faq-snippet\"\u003e\u003ch3\u003eFAQ\u003c\/h3\u003e\n\u003cdiv class=\"faq-item\"\u003e\n\u003cp class=\"faq-q\"\u003eQ: Is this thermostat the small Volvo version or the large one?\u003c\/p\u003e\n\u003cp class=\"faq-a\"\u003eA: This SeaSierra 383307 kit is the smaller Volvo-style thermostat. Confirm your existing thermostat size before ordering.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"faq-item\"\u003e\n\u003cp class=\"faq-q\"\u003eQ: What temperature does the thermostat open at?\u003c\/p\u003e\n\u003cp class=\"faq-a\"\u003eA: The thermostat is rated to open at 160°F (71°C).\u003c\/p\u003e\n\u003c\/div\u003e\u003c\/section\u003e","brand":"SeaSierra","offers":[{"title":"Default Title","offer_id":48084392411294,"sku":"B0DD3BRFB3","price":31.82,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0781\/2041\/9486\/files\/seasierra-thermostat-front-view.jpg?v=1785853385","url":"https:\/\/northtrailauto.ca\/products\/seasierra-thermostat-kit-for-omc-cobra-volvo-penta-4-3-5-8l-160-f-small-volvo-style","provider":"North Trail Auto","version":"1.0","type":"link"}