{"product_id":"acdelco-radiator-cap-rc85-15-psi-gm-oe-direct-fit-replacement-spring-loaded-seal","title":"ACDelco radiator cap RC85 15 PSI — GM OE direct-fit replacement, spring-loaded seal","description":"\u003cp\u003e\u003cstrong\u003eThe ACDelco GM Original Equipment RC85 (15042975) 15 P.S.I. radiator cap is a direct-fit, spring-loaded cap that seals the cooling system and maintains the correct 15 psi pressure for compatible GM vehicles.\u003c\/strong\u003e\u003c\/p\u003e\n\n\u003cp\u003eThis genuine GM-recommended radiator cap replaces the factory-fitted component to keep the cooling system sealed, manage pressure, and allow coolant recovery between the radiator and expansion tank as temperatures change. Built to original equipment specifications, this ACDelco cap matches the form, fit, and function expected for GM vehicles, helping preserve cooling system operation and longevity through stable pressure control.\u003c\/p\u003e\n\n\u003ch3\u003eHow does this radiator cap control coolant boiling point and pressure?\u003c\/h3\u003e\n\u003cp\u003eThe cap uses a calibrated spring and valve assembly to hold the system at 15 pounds per square inch (P.S.I.) while the engine is hot. Holding this pressure raises the coolant boiling point compared to an open system, helping the engine run within designed temperature ranges under load.\u003c\/p\u003e\n\u003cul\u003e\n  \u003cli\u003eCalibrated spring valves set to 15 P.S.I. for consistent pressure control\u003c\/li\u003e\n  \u003cli\u003eSeals the radiator filler neck or surge tank to prevent vapor loss\u003c\/li\u003e\n  \u003cli\u003eEngineered to minimize unintended coolant evaporation and boil-over\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003eWhat happens when the engine cools — will coolant be returned to the radiator?\u003c\/h3\u003e\n\u003cp\u003eYes. When the system temperature drops and pressure falls below the valve threshold, the cap allows coolant to flow back from the expansion tank into the radiator. This automatic recovery helps maintain the correct coolant level without manual topping-off in many scenarios.\u003c\/p\u003e\n\u003cul\u003e\n  \u003cli\u003eOne-way valve permits coolant return during cooldown cycles\u003c\/li\u003e\n  \u003cli\u003eMaintains system fill level to reduce air pockets and hot spots\u003c\/li\u003e\n  \u003cli\u003eDesigned to work with vehicles equipped with an expansion\/overflow tank\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003eIs this ACDelco cap a direct replacement for my GM vehicle’s original part?\u003c\/h3\u003e\n\u003cp\u003eACDelco GM Original Equipment caps are manufactured to GM specifications and listed as recommended replacements for compatible models. The RC85 (15042975) is vehicle-specific fit type, so matching the part number to your model year and engine application ensures correct fit and function.\u003c\/p\u003e\n\u003cul\u003e\n  \u003cli\u003eManufactured to GM OE specifications for reliability and durability\u003c\/li\u003e\n  \u003cli\u003eVehicle-specific fit; verify part compatibility with your GM model\u003c\/li\u003e\n  \u003cli\u003eReplaces the factory cap with matching performance characteristics\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003eHow do I know when the radiator cap needs replacing?\u003c\/h3\u003e\n\u003cp\u003eReplace the cap if you notice coolant loss, system overheating, or steam from the radiator neck. A failed cap can leak pressure, allow premature boiling, or fail to return coolant, so periodic inspection and replacement as part of cooling-system maintenance is advisable.\u003c\/p\u003e\n\u003cul\u003e\n  \u003cli\u003eLook for cracked seals, corrosion, or damaged spring action\u003c\/li\u003e\n  \u003cli\u003eSymptoms include coolant leakage, frequent low coolant level, or overheating\u003c\/li\u003e\n  \u003cli\u003eOEM replacement prevents mismatched pressures and inconsistent performance\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003cp\u003eWho is this for: The ACDelco RC85 15 P.S.I. radiator cap is intended for owners and technicians maintaining GM vehicles that list part number 15042975 or the RC85 spec. It’s suited to anyone wanting a factory-quality replacement that preserves designed cooling system pressure, supports coolant recovery, and matches GM original equipment standards. Choose this cap when you need a direct-fit, durable component that follows GM recommendations and helps avoid the issues caused by a worn or incorrect radiator cap.\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 the RC85 (15042975) cap the correct pressure for my GM car?\u003c\/p\u003e\n\u003cp class=\"faq-a\"\u003eA: This cap is calibrated to 15 P.S.I.; confirm compatibility by matching part 15042975 or RC85 to your vehicle's service manual or VIN parts listing.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"faq-item\"\u003e\n\u003cp class=\"faq-q\"\u003eQ: Can I reuse my old radiator cap if it looks intact?\u003c\/p\u003e\n\u003cp class=\"faq-a\"\u003eA: Visual condition alone can be misleading; replace caps showing seal damage, corrosion, or weak spring action to ensure proper pressure control.\u003c\/p\u003e\n\u003c\/div\u003e\u003c\/section\u003e","brand":"ACDelco","offers":[{"title":"Default Title","offer_id":55164272083287,"sku":"B000C9S78G","price":32.83,"currency_code":"GBP","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/1050\/1524\/7191\/files\/acdelco-rc85-front-view-cap.jpg?v=1790352039","url":"https:\/\/britishgarage.co.uk\/products\/acdelco-radiator-cap-rc85-15-psi-gm-oe-direct-fit-replacement-spring-loaded-seal","provider":"British Garage","version":"1.0","type":"link"}