Gates 33971 Engine Coolant Thermostat

Gates 33971 Heavy-Duty Thermostat Overview

The Gates 33971 Heavy-Duty Thermostat is an engine coolant thermostat built for demanding cooling systems in heavy-duty truck, bus, tractor, and equipment service. It uses brass and copper construction, a bottom by-pass design, and an O-ring seal to support stable coolant control in harsh under-hood conditions.

For buyers searching for a heavy-duty thermostat for diesel cooling system service, Gates 33971 delivers a direct replacement style solution with an 180°F opening temperature and a jiggle pin weep hole for air bleeding during service.

Key Features

• Heavy-Duty Thermostat design for severe-duty cooling environments
• Brass and copper construction for durability in high-heat applications
• Bottom by-pass design for proper coolant flow management
• Starts to open at 180°F / 82°C
• O-ring seal type for a secure housing interface
• Jiggle pin weep hole included for easier air purge
• Gates part number 33971 for catalog and cross-reference lookup

Product Details

Gates Heavy-Duty Thermostat line is built for vehicles and equipment that see constant vibration, heat cycling, and demanding duty cycles. Part number 33971 is a bottom by-pass engine coolant thermostat with a 2.94-inch sealing flange outside diameter, 2.86-inch overall height, and 1.44-inch height between flanges. The brass and copper body supports consistent thermal response, while the O-ring seal helps maintain a reliable seal at the housing.

This thermostat is a practical choice for heavy-duty cooling system repair where accurate coolant temperature control matters. It cross-references Remy 14868 for the same application. Search terms such as Gates 33971 thermostat, heavy-duty engine coolant thermostat, and 180 degree thermostat for truck cooling system repair are commonly used by technicians and parts buyers.

Common Problems This Part Can Address

• Engine running too cool or too hot due to thermostat wear
• Delayed coolant circulation after cold start
• Temperature fluctuation in heavy-duty cooling systems
• Coolant flow issues related to a failing by-pass thermostat
• Air trapped in the cooling system after service

Installation Notes and Tips

Verify housing style, by-pass configuration, and temperature rating before installation. Clean the thermostat housing sealing surfaces thoroughly and inspect the O-ring seat for damage or corrosion. Because this design includes a jiggle pin weep hole, position it according to the service procedure for the cooling system being repaired. Confirm the replacement matches the original Gates 33971 thermostat specification before reassembly.

Compatible With heavy-duty truck, bus, tractor, and equipment cooling system applications. For vehicle-specific searches, buyers often reference Gates 33971 when sourcing a heavy-duty thermostat for truck and diesel cooling repairs.

Quality Assurance

Gates manufactures the Green Stripe Heavy-Duty Thermostat line for severe-service cooling demands, using materials and design features selected for harsh operating conditions under the hood. Part number 33971 is built to meet the needs of heavy-duty cooling system service and replacement.