ACDelco Coolant Reservoir Cap – RC77 / 15530112

Genuine ACDelco coolant overflow reservoir cap, part number RC77 / 15530112, designed for factory coolant overflow tanks. Ensures proper cooling system pressure control and prevents coolant loss under temperature expansion. Perfect fit for 1986–1987 Turbo Buick 3.8L platforms and many GM vehicles using the same style cap.

🔵 Blue Dot – New / Never Installed

Specifications:
• Brand: ACDelco (OEM quality)
• Part Numbers: RC77 / 15530112 / EDEL119A / 7506055
• Type: Coolant overflow reservoir cap
• Fitment: 1986–1987 Buick Grand National / GNX / Turbo T / T-Type
• Compatible with additional GM V6 / V8 coolant tanks
• Material: Molded composite with internal rubber seal

Condition Notes:
• New — never installed
• Stored in box, clean and ready to install
• No cracks, wear, or sealing ring damage

Why You Want It:
Proper coolant pressure management is critical for preventing boil-over, leaks, and overheating — especially on boosted Turbo Buicks. A fresh OEM-spec cap helps maintain cooling efficiency, protects the head gaskets, and supports consistent performance under load and higher boost pressures.

⚠️ All Turbo 6 Parts are sold as-is with no returns, refunds, or exchanges. Buyer is responsible for verifying fitment and compatibility before purchase.