GXYWADY Coolant Overflow Tank HD81-87 for 1981–1991 GM Trucks with Cap — Heat‑Resistant, Direct-Fit

GXYWADY Coolant Overflow Tank with Cap (HD81-87) is a direct-fit replacement reservoir designed for 1981–1991 GM full-size trucks and SUVs to restore coolant containment and pressure control.

If your original coolant overflow tank has cracked, warped, or the cap no longer seals, this GXYWADY HD81-87 unit provides an OEM-style replacement made from heat- and vibration-resistant plastic. It fits classic CK-series trucks and related Blazer, Suburban, and RV pickup models covered by the original part numbers, and includes a matching cap to help re-establish correct coolant overflow and return behavior.

Which vehicles does this replacement tank fit?

This overflow tank is manufactured to replace the original reservoirs used on GM full-size vehicles from the early 1980s to early 1990s. Confirm fitment against your vehicle model year and CK-series or RV pickup application before ordering.

• Direct replacement for GM 1981–1987 CK series trucks.
• Compatible with 1988–1991 RV-style pickups, Blazer, and Suburban models.
• Listed under part number HD81-87 for cross-reference.
• Check your factory diagram to verify mounting points and hose connections.

How does the GXYWADY tank improve cooling system performance?

By restoring a properly sealed overflow reservoir, the tank helps the cooling system maintain correct fluid levels and pressure cycles during engine warm-up and cooldown. A functional tank reduces coolant loss and helps the system reintroduce returned fluid to the radiator instead of wasting it.

• Sealed cap reduces vapor loss and helps maintain system pressure.
• Proper overflow/return action minimizes air entry into coolant lines.
• Durable plastic resists heat and vibration for longer service life.
• Helps support consistent engine operating temperature management.

What are the build quality and material features?

The reservoir is molded from stabilized plastics chosen to withstand under-hood temperatures and engine vibration typical of older full-size trucks. The included cap is designed to mate securely and restore the original fit and sealing properties.

• Heat-resistant plastic construction for thermal durability.
• Vibration-tolerant design to resist cracks and leaks.
• Factory-style hose ports and mounting bosses for straightforward installation.
• Sold as a replacement assembly with matching cap included.

How easy is installation and what should I check before buying?

Installation is generally straightforward for someone with basic mechanical skills and standard hand tools: drain excess coolant as needed, remove the old tank, transfer any reusable fittings, and fasten the new tank in place. Always compare mounting points, hose diameters, and part number HD81-87 against your vehicle to ensure compatibility.

• Basic hand tools required; no major modifications expected.
• Verify hose sizes and mounting boss locations before purchase.
• Drain minimal coolant to prevent spills when swapping tanks.
• Re-use undamaged brackets or replace if corroded for secure fitment.

Who is this for: GXYWADY’s HD81-87 coolant overflow tank is intended for owners, restorers, and mechanics working on 1981–1987 CK-series GM trucks or 1988–1991 RV trucks, Blazers, and Suburbans who need a reliable, OEM-style replacement reservoir. It’s well suited for anyone restoring an older vehicle to safe operating condition or replacing a leaking or brittle factory tank without modifying the cooling system.