2003 Hummer H1 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

23 Coolant / Antifreeze parts for the 2003 Hummer H1 come from 6 brands — VALVOLINE, PRESTONE, PEAK and 3 other brands. The "Popular" part is FVP MV5050GAL.

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 4 options from FVP, PEAK, PRESTONE and 1 other brand — the catalog's value-priced group. FVP MV5050GAL is listed in this group.

In the Heavy Duty grade, VALVOLINE and PRESTONE supply 3 parts: rated for severe service. A representative part number is VALVOLINE ZXG051.

In the Premium grade, PRESTONE and PEAK supply 4 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, ACDELCO and 2 other brands supply 11 parts: built to original-equipment specification. A representative part number is ACDELCO 105027.

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

6 Coolant Hose / Pipe parts for the 2003 Hummer H1 come from 4 brands — ACDELCO, GATES, CONTINENTAL and 1 other brand. The "Popular" part is ACDELCO 20290S.

This group includes ACDELCO 20290S, GATES 22210 and ACDELCO 24234L and the remaining parts above.

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

3 Cooling System Tester Adapter parts for the 2003 Hummer H1 come from 3 brands — ACDELCO, GATES and MOTORAD.

Listed part numbers: ACDELCO 12A01, GATES 31413 and MOTORAD 3003.

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

5 Radiator Cap parts for the 2003 Hummer H1 come from 3 brands — GATES, MOTORAD and SKP. The "Popular" part is MOTORAD T16.

In the Locking Replacement grade, GATES and MOTORAD supply 2 parts: grouped under the catalog's "Locking Replacement" designation — the notes column spells out what sets them apart. A representative part number is GATES 31518.

Standard Replacement: 3 parts, from MOTORAD, GATES and SKP. A representative part number is MOTORAD T16.

This group includes MOTORAD T16, GATES 31518 and MOTORAD ST16 and the remaining 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

2 Radiator Fan Clutch parts for the 2003 Hummer H1 come from 2 brands — FVP and US MOTOR WORKS.

Part numbers include FVP 22618, 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

4 Radiator Hose parts are listed for the 2003 Hummer H1, from GATES, ACDELCO and CONTINENTAL.

Listed part numbers: ACDELCO 26371X, CONTINENTAL 66377 and GATES 20685, plus the other 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

11 Temperature Sender / Sensor parts for the 2003 Hummer H1 come from 8 brands — STANDARD MOTOR PRODUCTS, WALKER PRODUCTS, NTK and 5 other brands. The "Popular" part is NTK EF0008.

The Economy section: 5 options from NTK, STANDARD MOTOR PRODUCTS, GPD and 2 other brands. NTK EF0008 is listed in this group.

The Full Service Kit section lists 1 option from WALKER PRODUCTS — grouped under the catalog's "Full Service Kit" designation — the notes column spells out what sets them apart. WALKER PRODUCTS 21191012 is listed in this group.

Standard Replacement: 5 parts, from STANDARD MOTOR PRODUCTS, HELLA, WALKER PRODUCTS and 1 other brand. A representative part number is STANDARD MOTOR PRODUCTS TX3.

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

3 Thermostat parts are listed for the 2003 Hummer H1, from MOTORAD and GATES.

Listed part numbers: GATES 33922, MOTORAD 423195 and MOTORAD 423180.

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

9 Thermostat / Thermostat Housing / Water Outlet Seal parts for the 2003 Hummer H1 come from 4 brands — FEL-PRO, MAHLE / CLEVITE, APEX and 1 other brand. The "Popular" part is FEL-PRO 35710.

Listed part numbers: FEL-PRO 35710, MAHLE / CLEVITE C31273 and APEX AWO2148, plus the other 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

6 Water Pump parts are listed for the 2003 Hummer H1, from FVP, US MOTOR WORKS, ACDELCO and 3 other brands. ACDELCO 252776 carries the "Popular" badge.

Economy: 2 parts, from FVP and US MOTOR WORKS. A representative part number is FVP US5086.

The Standard Replacement section: 4 options from ACDELCO, GATES, DAYCO and 1 other brand. ACDELCO 252776 is listed in this group.

This group includes ACDELCO 252776 and FVP US5086 and the remaining parts above.

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

One part is listed for the 2003 Hummer H1 — US MOTOR WORKS MCK1043.

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

5 Water Pump Gasket parts for the 2003 Hummer H1 come from 3 brands — FEL-PRO, APEX and VICTOR REINZ. The "Popular" part is FEL-PRO ES72674.

Part numbers include FEL-PRO ES72674, APEX AWP3209 and FEL-PRO 36180, among others listed above.