2026 GMC Terrain Cooling System Parts

This table covers the engine coolants and antifreeze formulations specified for this cooling system. Typical signs include a rising temperature gauge, rusty or sludged coolant, or a heater that blows cold. Use the chemistry named in the notes. Mixing silicate, OAT and HOAT formulas can gel in the radiator. Read more

11 Coolant / Antifreeze parts for the 2026 GMC Terrain come from 3 brands — PRESTONE, VALVOLINE and ACDELCO. The "Popular" part is PRESTONE AF2100.

In the Compatible With All Colors grade, PRESTONE supplies 1 part: grouped under the catalog's "Compatible With All Colors" designation — the notes column spells out what sets them apart. A representative part number is PRESTONE AF3055.

The Economy section lists 2 options from PRESTONE and VALVOLINE — the catalog's value-priced group. PRESTONE AF3100 is listed in this group.

In the Heavy Duty grade, PRESTONE supplies 1 part: rated for severe service. A representative part number is PRESTONE AFC12100.

In the Premium grade, PRESTONE supplies 2 parts: a step above OE specification in materials, tolerances or warranty terms. A representative part number is PRESTONE AF2100.

In the Standard Replacement grade, VALVOLINE, PRESTONE and ACDELCO supply 5 parts: built to original-equipment specification. A representative part number is ACDELCO 105027.

This table covers the Coolant Air Bleed Hose pipes. Read more

4 Coolant Air Bleed Hose / Pipe parts for the 2026 GMC Terrain come from GM GENUINE.

Listed part numbers: GM GENUINE 12650443, GM GENUINE 26572782 and GM GENUINE 26572783, plus the other parts above.

This table covers the hard pipes and extra hoses in the coolant circuit. Read more

2 Coolant Hose / Pipe parts for the 2026 GMC Terrain come from GM GENUINE.

Listed part numbers: GM GENUINE 12649871 and GM GENUINE 12667458.

This table covers the seals at the Coolant Hose / Pipe. Typical signs include a wet housing, a drip after sitting, or fluid flung off a rotating shaft. Fix the surface the seal rides on. A new seal on a grooved shaft will leak again. Read more

GM GENUINE supplies both parts for the 2026 GMC Terrain.

Listed part numbers: GM GENUINE 12635750 and GM GENUINE 12662185.

This table covers the overflow / expansion tanks that hold extra coolant. Read more

3 Coolant Reservoir parts are listed for the 2026 GMC Terrain, from GM GENUINE, GPD and TECHPRO.

Part numbers include GM GENUINE 23386455, GPD 2411160 and TECHPRO GM3014175.

This table covers the Hose clamps. Read more

5 Hose Clamp parts for the 2026 GMC Terrain come from GM GENUINE. The "Popular" part is GM GENUINE 90530642.

Listed part numbers: GM GENUINE 90530642, GM GENUINE 90572594 and GM GENUINE 11602210, plus the other parts above.

This table covers the intercoolers that cool turbo or supercharger charge air. Read more

4 Intercooler parts for the 2026 GMC Terrain come from 4 brands — GM GENUINE, GPD, SPECTRA PREMIUM and 1 other brand.

Listed part numbers: GM GENUINE 85046823, GPD 2711386 and SPECTRA PREMIUM 44011221, plus the other parts above.

This table covers the Intercooler Air Hose pipes. Read more

2 Intercooler Air Hose / Pipe parts for the 2026 GMC Terrain come from GM GENUINE.

Listed part numbers: GM GENUINE 26531060 and GM GENUINE 26343819.

This table covers the radiators that dump engine heat to airflow through the core. Typical signs include overheating in traffic, a wet core, or coolant that disappears with no puddle. Replace the cap if it cannot hold the rated pressure, and bleed the system after the swap. Read more

4 Radiator parts for the 2026 GMC Terrain come from 4 brands — CSF, GM GENUINE, SPECTRA PREMIUM and 1 other brand.

This group includes CSF 3866, GM GENUINE 84989891 and SPECTRA PREMIUM CU13691 and the remaining parts above.

This table covers the caps that hold system pressure at the radiator or reservoir neck. Typical signs include a leak at the neck, a cap that will not hold pressure, or a missing tether. Match the pressure rating or thread in the notes — radiator, reservoir and fuel caps are not interchangeable. Read more

This group shows a single part: ACDELCO RC124.

This table covers the petcocks used to drain the radiator. Read more

One part is listed for the 2026 GMC Terrain — ACDELCO 22985584.

This table covers the fan assemblies (and clutches, where listed) that pull air through the radiator. Read more

3 Radiator Fan Assembly parts are listed for the 2026 GMC Terrain, from GM GENUINE and TYC.

This group includes GM GENUINE 86285697, GM GENUINE 85109720 and TYC 625250.

This table covers the seals at the Radiator. Typical signs include a wet housing, a drip after sitting, or fluid flung off a rotating shaft. Fix the surface the seal rides on. A new seal on a grooved shaft will leak again. Read more

GM GENUINE supplies the 3 Radiator Seal parts for the 2026 GMC Terrain.

Listed part numbers: GM GENUINE 23270572, GM GENUINE 85607646 and GM GENUINE 85607647.

This table covers the senders that report coolant temperature to the gauge or ECU. Typical signs include a gauge that sits on empty or overheat, or a lamp that does not match what the engine is doing. Rule out the cluster and the wiring before replacing the sender. Read more

2 Temperature Sender / Sensor parts for the 2026 GMC Terrain come from 2 brands — HOLSTEIN and GM GENUINE.

The Economy section: 1 option from HOLSTEIN. HOLSTEIN 2CTS0125 is listed in this group.

Standard Replacement: 1 part, from GM GENUINE. A representative part number is GM GENUINE 55489870.

Part numbers include HOLSTEIN 2CTS0125 and GM GENUINE 55489870.

This table covers the thermostats that open the coolant circuit at the specified temperature. Typical signs include slow warm-up, a gauge that climbs in traffic, or heat that never quite arrives. Replace the housing gasket with the thermostat and bleed the system so a trapped air pocket does not cook the new part. Read more

One part is listed for the 2026 GMC Terrain — MOTORAD 993176.

This table covers the seals at the thermostat housing and water outlet. Typical signs include a wet housing, a drip after sitting, or fluid flung off a rotating shaft. Fix the surface the seal rides on. A new seal on a grooved shaft will leak again. Read more

2 Thermostat / Thermostat Housing / Water Outlet Seal parts for the 2026 GMC Terrain come from GM GENUINE.

Part numbers include GM GENUINE 12664202 and GM GENUINE 12649163.

This table covers the housings and outlets the thermostat sits in. Read more

3 Thermostat Housing / Water Outlet parts are listed for the 2026 GMC Terrain, from GM GENUINE and MOTORAD.

Part numbers include GM GENUINE 12707589, GM GENUINE 25205818 and MOTORAD CH2746.

This table covers the pumps that circulate coolant through the block and radiator. Typical signs include coolant at the weep hole, pulley play, or a growl from the front of the engine. Replace the thermostat and refill with the specified coolant whenever the pump comes off. Read more

2 Water Pump parts are listed for the 2026 GMC Terrain, from DAYCO and GM GENUINE.

This group includes DAYCO DP2255 and GM GENUINE 25205820.

This table covers the gaskets between the water pump and the block or housing. Typical signs include seepage at the joint, a burnt-oil smell, or a leak that appears only after a long drive. Clean both flanges and torque in the sequence the notes or the manual call for. Read more

2 Water Pump Gasket parts for the 2026 GMC Terrain come from GM GENUINE.

Part numbers include GM GENUINE 2512070 and GM GENUINE 2512067.

This table covers the Water Pump housings. Read more

This group shows a single part: GM GENUINE 25204308.

This table covers the Water Pump pulleys. Typical signs include a growl or chirp that follows engine speed, or a pulley that will not spin freely by hand. Spin each pulley with the belt off. Roughness or play means replace it with the belt. Read more

This group shows a single part: GM GENUINE 12642753.