Amazon.com: Partuto 1Pc 16mm 0.63" ID Universal Silicone Coolant Cap Intake Vacuum Hose End Plug - Car for Coolant Heater Bypass Vacuum Water Port - Silicone Black : Automotive
Rubber Block Off Blank Caps Heater Hose Water Pumps Universal 16mm 5/8" x 2 | eBay
Heater Hose Delete Cap (sold individually)
CAP KIT, Heater Core / Heater Hose Block off, 3/4 inch diameter, (2) - #C-8854-60K - National Parts Depot
CAP KIT, Heater Core / Heater Hose Block off, 5/8 inch diameter, (2) - #C-8854-61K - National Parts Depot
K-Tuned Heater Hose Delete Cap Honda Civic,CRX,Integra | Fullcartuning.com