{"product_id":"castair-cast-lube-1-gal-5w-30-wt-high-quality-oil-for-piston-compressors-semi-synthetic-ga5w30","title":"Castair CAST-LUBE 1 Gal 5w \/ 30 Wt. High Quality Oil for Piston Compressors Semi Synthetic GA5W30","description":"\u003ch2\u003eCastair CAST-LUBE Semi-Synthetic Compressor Oil for Piston Compressors — 1 Gallon, 5W30\u003c\/h2\u003e\n\u003cp\u003eThe GA5W30 is the standard piston compressor oil in the CAST-LUBE lineup — a high-quality semi-synthetic 5W30 formulated specifically for air-cooled piston-type compressors. At 8.50 per gallon, it is the most affordable oil Castair makes, and it handles the core job well: lubricate the crankshaft, connecting rods, cylinder walls, and valve train without creating carbon deposits, foaming, or breaking down under the heat of a loaded compressor cycle. The service interval is 400 hours or 4 months — which for moderate-duty shop compressors typically aligns well with seasonal oil change practices.\u003c\/p\u003e\n\n\u003ch2\u003eWhy Compressor Oil Is Not Just Motor Oil\u003c\/h2\u003e\n\u003cp\u003eThis is the most common mistake shops make. Motor oil — even 5W30 — contains detergent additives that foam under pressure cycling and deposit varnish on compressor valve faces. Compressor valves are precision ground and operate at very tight clearances; deposits cause them to leak, reducing compressor efficiency and eventually causing valve failure. CAST-LUBE is formulated without those detergents. It is non-foaming, low-carbon, and designed to stay clean through the full service interval on a piston compressor. Using motor oil in your Castair piston compressor voids the warranty.\u003c\/p\u003e\n\n\u003ch3\u003eCAST-LUBE Semi-Synthetic 5W30 Features\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eSemi-Synthetic Base:\u003c\/strong\u003e Multi-grade 5W30 formulation balances cost and performance — better cold-start flow than straight mineral oil, better high-temp stability than conventional grades\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e-37°F Pour Point:\u003c\/strong\u003e Flows freely even in unheated shops or cold climates — important for compressors that sit in cold buildings overnight and start up cold in the morning\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eLow Carbon Formula:\u003c\/strong\u003e Resists deposit buildup on valve seats, piston rings, and cylinder walls — the primary failure mode for neglected piston compressors\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eNon-Foaming:\u003c\/strong\u003e Stays liquid under pressure cycling — foam in compressor oil leads to oil carryover in discharge air and accelerated wear\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eHigh Temperature Rating:\u003c\/strong\u003e Maintains film strength at operating temperatures of air-cooled piston compressors running under load\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eAll-Season Universal:\u003c\/strong\u003e One oil year-round — no seasonal changeover required\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eFactory Approved:\u003c\/strong\u003e Castair's specified semi-synthetic lubricant for piston compressor product line\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e400-Hour Service Rating:\u003c\/strong\u003e Recommended change at 400 hours or 4 months — well-suited to shop compressors running moderate duty cycles\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch2\u003eGA5W30 vs. GA10W30 — Which Oil Does Your Compressor Need?\u003c\/h2\u003e\n\u003cp\u003eBoth oils are approved for Castair piston compressors. The choice depends on duty cycle and how often you want to do oil changes:\u003c\/p\u003e\n\n\u003ch3\u003eSemi-Synthetic Options\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eQT5W30 — Semi-Synthetic 5W30, 1 Quart:\u003c\/strong\u003e Same formula, smaller volume for top-offs or small compressors\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eGA5W30 — Semi-Synthetic 5W30, 1 Gallon (8.50) — THIS PRODUCT:\u003c\/strong\u003e Standard service oil for Castair piston compressors. 400 hours or 4 months between changes.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003eFull Synthetic Options (Extended Service)\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eQT10W30 — Full Synthetic 10W30, 1 Quart:\u003c\/strong\u003e Top-off or small compressor fill\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eGA10W30 — Full Synthetic 10W30, 1 Gallon (3.91):\u003c\/strong\u003e Double the service interval — 800 hours or 8 months. Better choice for high-duty-cycle compressors or shops that want to minimize maintenance frequency.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch2\u003eWhen the Semi-Synthetic Is the Right Call vs. Stepping Up to Full Synthetic\u003c\/h2\u003e\n\u003cp\u003eFor most shop compressors running 2-6 hours per day in moderate temperatures, the GA5W30 is the correct oil. It meets factory specification, it protects the pump properly, and at 8.50 per gallon it is easy to stay on a regular change schedule without watching the budget.\u003c\/p\u003e\n\u003cp\u003eConsider upgrading to GA10W30 full synthetic if:\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003eYour compressor runs continuous or near-continuous duty — 8+ hours a day\u003c\/li\u003e\n\u003cli\u003eThe shop runs hot in summer and you want extra thermal margin\u003c\/li\u003e\n\u003cli\u003eYou want to cut oil change frequency in half (800-hour vs. 400-hour interval)\u003c\/li\u003e\n\u003cli\u003eYou are running a large-HP compressor where pump longevity is the priority\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch2\u003eWhat's in the Box\u003c\/h2\u003e\n\u003cul\u003e\n\u003cli\u003e1 gallon (128 fl. oz.) of Castair CAST-LUBE Semi-Synthetic 5W30 Piston Compressor Oil\u003c\/li\u003e\n\u003cli\u003eFactory-sealed container\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch2\u003eTechnical Specifications\u003c\/h2\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003ePart Number:\u003c\/strong\u003e GA5W30\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eVolume:\u003c\/strong\u003e 1 gallon (128 fl. oz.)\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eOil Type:\u003c\/strong\u003e Semi-synthetic\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eViscosity Grade:\u003c\/strong\u003e Multi-grade 5W30\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003ePour Point:\u003c\/strong\u003e -37°F\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eService Interval:\u003c\/strong\u003e 4 months or 400 hours (whichever comes first)\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eApplication:\u003c\/strong\u003e Piston-type air compressors (NOT for rotary screw)\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eApproved By:\u003c\/strong\u003e Castair factory specification\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003eWhy Buy From Air Compressor Factory Direct?\u003c\/h3\u003e\n\u003cp\u003eWe specialize in Castair compressors and genuine Castair parts and consumables, and have since 2016. We stock the complete CAST-LUBE line — semi-synthetic, full synthetic, and rotary screw formulas — and can advise which oil your specific Castair unit requires. Free shipping on orders, free technical support at 866-217-0063, and honest guidance on whether the semi-synthetic or full synthetic is right for your duty cycle.\u003c\/p\u003e\n\n\u003cp\u003e\u003cstrong\u003eCall 866-217-0063 for quick answers and help!\u003c\/strong\u003e\u003c\/p\u003e","brand":"Cast Air","offers":[{"title":"Default Title","offer_id":53342552522965,"sku":"GA5W30","price":71.0,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0622\/8466\/0949\/files\/OIL_new-768x339.jpg?v=1772652697","url":"https:\/\/aircompressorfactorydirect.com\/products\/castair-cast-lube-1-gal-5w-30-wt-high-quality-oil-for-piston-compressors-semi-synthetic-ga5w30","provider":"Air Compressor Factory Direct","version":"1.0","type":"link"}