On the T1 Silverado, coolant service is less about tricky fasteners and more about air. Most of these radiators have no usable petcock, so you drain by pulling the lower radiator hose with spring-clamp pliers and letting roughly three gallons hit the pan at once. The only fill point is the surge tank, and the heater core and rear of the block will hold air pockets that make the heat blow cold and the temp gauge wander.
The one thing people get wrong is the refill. Dumping coolant in the tank, starting the engine and calling it done leaves air in the system every time. Either rent a vacuum fill tool or commit to a proper burp: spill-free funnel, heater on full hot, idle and rev in cycles until the level stops dropping, then recheck cold the next morning. Second most common mistake: topping off with the wrong coolant. It is Dex-Cool orange, nothing else.
| Item | Type | |
|---|---|---|
| Floor jack 2-ton minimum Lift the front of the truck to reach the lower radiator hose and splash shields. | Required | shop |
| Jack stands 3-ton pair Support the truck on the frame rails while you work underneath. | Safety | shop |
| Wheel chocks Keep the truck from rolling while the front is lifted. | Safety | shop |
| Nitrile gloves and safety glasses Coolant is a skin and eye irritant and will pour out at the hose. | Safety | shop |
| Socket set, metric 7, 8, 10, 13, 15 mm, 3/8 in drive with 6 in extension Removes the lower air deflector, skid plate and fan shroud fasteners to reach the hose. | Required | shop |
| 1/4 in drive ratchet and 7/8 mm sockets 7 mm and 8 mm Most GM plastic shield and clamp screws under the front are 7 mm or 8 mm hex head. | Required | shop |
| Hose clamp pliers Spring (constant-tension) clamp pliers, cable type preferred The lower radiator and heater hoses use factory spring clamps that are nearly impossible to move with regular pliers in tight quarters. | Required | shop |
| Drain pan 4 US gal / 15 L low-profile Catches the full system volume dumping out of the lower hose at once. | Required | shop |
| Hose pick / trim tool set Plastic pry tools plus 90-degree pick Frees stuck hoses from the radiator neck and pops plastic push-pin clips on the air deflector without breaking them. | Recommended | shop |
| Funnel with no-spill adapter GM/universal coolant spill-free funnel kit Lets you fill the surge tank above its neck and burp air out while the engine warms. | Required | shop |
| Vacuum coolant fill tool Shop-air venturi type, universal cone adapters Pulls the system into vacuum and fills with no trapped air, which is the reliable way to avoid heater-core air pockets on this truck. | Recommended | shop |
| Air compressor 90 psi, ~4 CFM to run the vacuum tool Powers the venturi on the vacuum fill kit. | Recommended | shop |
| Flat screwdriver Medium, 6 in Backs off worm-gear clamps if a previous owner replaced factory spring clamps, and pops clips. | Recommended | shop |
| Torque wrench 3/8 in drive, 5-75 ft-lb Retorques skid plate and shield bolts without stripping the aluminum or plastic threads. | Recommended | shop |
| Bi-directional scan tool OBD-II with GM engine cooling fan / bleed function Commands the cooling fans and lets you watch coolant temperature during the bleed instead of guessing. | Recommended | shop |
| Infrared thermometer Confirms the upper hose and heater hoses are both hot, proving the thermostat opened and air is out. | Recommended | shop |
| Coolant hydrometer or refractometer Ethylene glycol scale Verifies freeze protection after topping off, especially if you mixed concentrate. | Recommended | shop |
| Dex-Cool coolant GM Dex-Cool orange, 50/50 premix; 2 gal for 2.7L, 3-4 gal for 5.3/6.2 and Duramax This is the specified long-life OAT coolant; do not substitute green IAT or pink HOAT. | Consumables | shop |
| Distilled water 1-2 gal For mixing concentrate or rinsing; never use tap water in a Dex-Cool system. | Consumables | shop |
| Spring hose clamps or worm clamps Sized to lower radiator hose, ~1.5-1.75 in Replace any factory spring clamp that has lost tension or gets deformed during removal. | Parts | shop |
| Shop towels and degreaser Coolant on the crossmember and driveway needs cleaning up before pets find it. | Consumables | shop |
| Coolant storage jug Sealable 5 gal Old coolant must be stored and taken to a recycling center, not poured down a drain. | Consumables | shop |
Hand tools are the same across all four engines; only access and volume change. The 2.7 L L3B holds noticeably less coolant (around 2 gallons of premix) and its front-end packaging is tighter around the turbo coolant lines, while the 5.3 L L84 and 6.2 L L87 typically take 3-3.5 gallons. The 3.0 L LM2/LZ0 Duramax has more plumbing and additional bleed/vent points plus a lower underbody shield with extra 10 and 13 mm bolts, so budget more time and confirm its bleed sequence in the manual.
| Front lower air deflector / splash shield bolts | verify in the service manual (hand-snug, typically under 10 ft-lb into plastic) |
| Front skid plate / underbody shield bolts | verify in the service manual |
| Worm-gear hose clamp screw | 35-45 in-lb (4-5 Nm), snug only |
| Radiator drain plug (if equipped) | verify in the service manual (hand-tight plastic) |
| Fan shroud fasteners | verify in the service manual |
Fastener sizes (7, 8, 10, 13, 15 mm) and the Dex-Cool requirement are solid across the T1 generation, but radiator drain plug presence, exact system capacity and the torque values vary by engine and build date — confirm capacity and torques in the factory service manual or your owner's manual for your VIN.
Many T1 radiators do not have an accessible petcock, and on builds that do it is a plastic plug on the lower driver-side tank behind the air deflector. Plan on draining by pulling the lower radiator hose with spring-clamp pliers, and check for a plug once the shield is off.
GM Dex-Cool, the orange long-life OAT coolant, in a 50/50 mix with distilled water. All four engines (2.7T, 5.3, 6.2, 3.0 Duramax) use it; do not mix in green conventional or pink HOAT coolant.
Roughly 2 gallons of premix for the 2.7 L turbo and about 3-3.5 gallons for the 5.3 L and 6.2 L; the 3.0 Duramax is in the same range but with more plumbing. Buy an extra gallon and verify the exact capacity for your VIN in the service manual.
That is almost always air trapped in the heater core. Re-burp with a spill-free funnel: heater on full hot and high fan, idle with bursts to about 2000 rpm until bubbles stop and the level holds, then top off cold the next morning. A vacuum fill tool avoids the problem entirely.