2003 Hummer H2 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

17 Coolant / Antifreeze parts are listed for the 2003 Hummer H2, from PRESTONE, PEAK, VALVOLINE and 3 other brands. FVP MV5050GAL carries the "Popular" badge.

The Compatible With All Colors section lists 1 option from PRESTONE — grouped under the catalog's "Compatible With All Colors" designation — the notes column spells out what sets them apart. PRESTONE AF3055 is listed in this group.

In the Economy grade, FVP, PEAK, PRESTONE and 1 other brand supply 4 parts: the catalog's value-priced group. A representative part number is FVP MV5050GAL.

The Heavy Duty section lists 1 option from PRESTONE — rated for severe service. PRESTONE AFC12100 is listed in this group.

The Premium section lists 4 options from PRESTONE and PEAK — a step above OE specification in materials, tolerances or warranty terms. PRESTONE AF2100 is listed in this group.

The Standard Replacement section lists 7 options from VALVOLINE, PRESTONE, ACDELCO and 2 other brands — built to original-equipment specification. ACDELCO 105027 is listed in this group.

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

2 Coolant Air Bleed Hose / Pipe parts are listed for the 2003 Hummer H2, from SKP and DORMAN.

Economy: 1 part, from SKP. A representative part number is SKP SK626543.

The Standard Replacement section: 1 option from DORMAN. DORMAN 626543 is listed in this group.

Part numbers include SKP SK626543 and DORMAN 626543.

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

2 Coolant Hose / Pipe parts are listed for the 2003 Hummer H2, from ACDELCO and GM GENUINE.

Part numbers include ACDELCO 20192S and GM GENUINE 15058002.

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

2 Coolant Hose / Pipe Seal parts for the 2003 Hummer H2 come from 2 brands — DORMAN and ELRING.

Part numbers include DORMAN 56390 and ELRING 868630.

This table covers the Coolant Hose retainers and clips. Read more

One part is listed for the 2003 Hummer H2 — GM GENUINE 15041309.

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

5 Coolant Reservoir parts for the 2003 Hummer H2 come from 5 brands — DORMAN, AUTOTECNICA, GPD and 2 other brands. The "Popular" part is DORMAN 603102.

Listed part numbers: DORMAN 603102, AUTOTECNICA GM0713009 and GPD 2411022, plus the other parts above.

This table covers the caps on the overflow / expansion tank. 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

3 Coolant Reservoir Cap parts for the 2003 Hummer H2 come from 3 brands — AUTOTECNICA, CALORSTAT and MOTORAD.

This group includes AUTOTECNICA GM0613020, CALORSTAT RC0147 and MOTORAD T46.

This table covers the Coolant Water Crossover Mounting sets. Read more

3 Coolant Water Crossover Mounting Set parts are listed for the 2003 Hummer H2, from FEL-PRO, MAHLE / CLEVITE and VICTOR REINZ.

Listed part numbers: FEL-PRO ES73027, MAHLE / CLEVITE GS33845 and VICTOR REINZ 181002301.

This table covers the Cooling Fan control modules. Read more

3 Cooling Fan Control Module parts for the 2003 Hummer H2 come from US MOTOR WORKS.

Listed part numbers: US MOTOR WORKS 16749, US MOTOR WORKS 16789 and US MOTOR WORKS 16795.

This table covers the adapters used to pressure-test this cooling system. Read more

4 Cooling System Tester Adapter parts are listed for the 2003 Hummer H2, from GATES and MOTORAD.

Part numbers include GATES 31431, GATES 31391 and MOTORAD 3128, among others listed above.

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

19 Radiator parts are listed for the 2003 Hummer H2, from OSC, LILAND GLOBAL, KOYORAD and 8 other brands. OSC 2423E carries the "Popular" badge.

Economy: 3 parts, from OSC and TECHPRO. A representative part number is OSC 2423E.

In the Premium (All Aluminum Construction) grade, LILAND GLOBAL supplies 2 parts: a step above OE specification in materials, tolerances or warranty terms. A representative part number is LILAND GLOBAL 2370AA.

The Standard Replacement section: 14 options from OSC, KOYORAD, CSF and 6 other brands. KOYORAD A2370 is listed in this group.

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

2 Radiator Cap parts are listed for the 2003 Hummer H2, from ACDELCO and GATES.

This group includes ACDELCO RC98 and GATES 31532.

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

This group shows a single part: DORMAN 61136.

This table covers the Radiator Fan blades. Typical signs include chatter, streaks, or a skip at the top of the stroke. Confirm left and right lengths in the notes — they are often different. Read more

4 Radiator Fan Blade parts for the 2003 Hummer H2 come from 4 brands — DORMAN, FOUR SEASONS, GM GENUINE and 1 other brand.

Listed part numbers: DORMAN 620602, FOUR SEASONS 36893 and GM GENUINE 1580712, plus the other parts above.

This table covers the Radiator Fan clutches. Typical signs include slip at highway speed, chatter on takeoff, or a pedal that stays low. Resurface or replace the flywheel with the clutch — a heat-checked flywheel wastes the new disc. Read more

7 Radiator Fan Clutch parts are listed for the 2003 Hummer H2, from FOUR SEASONS, HAYDEN, FVP and 4 other brands. FOUR SEASONS 36973 carries the "Popular" badge.

Part numbers include FOUR SEASONS 36973, HAYDEN 2786 and FVP 22158, among others listed above.

This table covers the upper, lower and connecting hoses between radiator, engine and reservoir. Typical signs include swelling, cracks, a soft spot, or a leak at a clamp. Replace adjacent aged hoses while the system is drained — they share the same heat cycle. Read more

8 Radiator Hose parts for the 2003 Hummer H2 come from 4 brands — ACDELCO, GATES, CONTINENTAL and 1 other brand. The "Popular" part is ACDELCO 26390X.

This group includes ACDELCO 26390X, GATES 22436 and ACDELCO 22463M and the remaining parts above.

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

17 Temperature Sender / Sensor parts are listed for the 2003 Hummer H2, from STANDARD MOTOR PRODUCTS, WALKER PRODUCTS, SKP and 12 other brands. SKP SKTX89 carries the "Popular" badge.

Economy: 6 parts, from SKP, DORMAN, GPD and 3 other brands. A representative part number is SKP SKTX89.

In the Full Service Kit grade, WALKER PRODUCTS supplies 1 part: grouped under the catalog's "Full Service Kit" designation — the notes column spells out what sets them apart. A representative part number is WALKER PRODUCTS 21191012.

The Standard Replacement section: 10 options from ACDELCO, GM GENUINE, STANDARD MOTOR PRODUCTS and 7 other brands. ACDELCO 2134514 is listed in this group.

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

30 Thermostat parts for the 2003 Hummer H2 come from 7 brands — MOTORAD, CALORSTAT, DORMAN and 4 other brands. The "Popular" part is MOTORAD 5456187. Grades run from Economy through Standard Replacement; Standard Replacement is the most populated section, led by MOTORAD, CALORSTAT, GATES and 2 other brands.

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

4 Thermostat / Thermostat Housing / Water Outlet Seal parts are listed for the 2003 Hummer H2, from APEX, FEL-PRO, MAHLE / CLEVITE and 1 other brand.

Part numbers include APEX AWO2088, FEL-PRO 35632 and MAHLE / CLEVITE 72141, among others listed above.

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

7 Thermostat Housing / Water Outlet parts for the 2003 Hummer H2 come from 7 brands — DORMAN, AUTOTECNICA, FAMOUS BRAND and 4 other brands. The "Popular" part is DORMAN 902836.

The Economy section: 4 options from DORMAN, AUTOTECNICA, FAMOUS BRAND and 1 other brand. DORMAN 902836 is listed in this group.

Standard Replacement: 3 parts, from MOTORAD, FOUR SEASONS and GATES. A representative part number is MOTORAD CH2836.

This group includes DORMAN 902836, AUTOTECNICA GM0718508 and FAMOUS BRAND 85254 and the remaining parts above.

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

17 Water Pump parts for the 2003 Hummer H2 come from 11 brands — SKP, US MOTOR WORKS, FVP and 8 other brands. The "Popular" part is SKP SK1307340.

The Economy section: 7 options from SKP, US MOTOR WORKS, FVP and 1 other brand. SKP SK1307340 is listed in this group.

Standard Replacement: 10 parts, from GATES, GMB, MELLING and 4 other brands. A representative part number is GATES 45006.

This table covers the Water Pump & Fan Clutch assemblies. Read more

4 Water Pump & Fan Clutch Assembly parts for the 2003 Hummer H2 come from 3 brands — US MOTOR WORKS, FVP and GMB.

This group includes FVP 1300003 and US MOTOR WORKS MCK1007 and the remaining parts above.

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

9 Water Pump Gasket parts are listed for the 2003 Hummer H2, from FEL-PRO, VICTOR REINZ, GM GENUINE and 4 other brands. FEL-PRO ES73010 carries the "Popular" badge.

Listed part numbers: FEL-PRO ES73010, GM GENUINE 251663 and APEX AWP3016, plus the other parts above.

This table covers the Water Pump Seal O-rings. Typical signs include a seep at a fitting or a housing that weeps after a service. Lube the new O-ring with the fluid it will see, and do not roll it into the groove. Read more

5 Water Pump Seal / O-Ring parts for the 2003 Hummer H2 come from 5 brands — FEL-PRO, APEX, GM GENUINE and 2 other brands. The "Popular" part is FEL-PRO 35633.

This group includes FEL-PRO 35633, APEX AWP3151 and GM GENUINE 12561155 and the remaining parts above.