Coolant service on the K2XX Silverado is one of the easier fluid jobs, with one catch: many of these trucks have no usable radiator petcock, so you drain by pulling the lower radiator hose off the driver side. That means a set of ratcheting hose clamp pliers for the factory spring clamp and a low-profile pan, because about three gallons comes out fast and mostly where you do not want it.
The part people get wrong is the refill. There is no bleeder screw anywhere on the 4.3, 5.3 or 6.2, so if you just fill the surge tank and cap it you will get an air pocket, a heater that blows cold, and erratic temp readings. Use a spill-free funnel and idle the truck with the heat on full until the bubbling stops and the fans cycle. Also remember a drain-and-fill only replaces roughly two thirds of the system unless you pull the block drains, so use 50/50 premix and recheck the level cold after a drive.
| Item | Type | |
|---|---|---|
| Floor jack 2 ton minimum Lift the front of the truck to reach the lower radiator hose and drain point. | Required | shop |
| Jack stands 3 ton pair Support the truck while you work underneath. | Safety | shop |
| Wheel chocks Block the rear wheels before lifting. | Safety | shop |
| Socket set, 3/8 in drive 7, 8, 10, 13, 15 mm Removes the lower air dam, splash shields and any belly pan in front of the radiator. | Required | shop |
| 1/4 in drive ratchet and 7 mm socket 7 mm shallow socket Most GM plastic splash-shield screws and worm-gear hose clamps use a 7 mm hex head. | Required | shop |
| Trim/push-pin removal tool Plastic fastener remover Pops the plastic push pins holding the front splash shields without breaking them. | Recommended | shop |
| Ratcheting hose clamp pliers Flexible cable type for spring clamps The lower radiator hose uses a factory spring clamp in a tight spot; these hold it open. | Required | shop |
| Drain pan 3 gallon / low profile Catches roughly 3-3.5 gallons of coolant when the hose comes off. | Required | shop |
| Hose pick or small pry tool Breaks the lower hose loose from the radiator neck without tearing it. | Recommended | shop |
| Spill-free funnel kit Universal coolant funnel with GM adapters Lets you fill and burp the system at the surge tank without airlocks or spills. | Required | shop |
| Fluid transfer pump or long-neck funnel Handy for adding coolant into the surge tank neck in the tight engine bay. | Recommended | shop |
| Refractometer or coolant tester Ethylene glycol scale Confirms the finished mix gives roughly -34 F protection. | Recommended | shop |
| Shop rags and parts brush Dex-Cool residue is slick and stains driveways; clean as you go. | Consumables | shop |
| Dex-Cool coolant 50/50 premixed orange (GM 12378560 spec); 3-4 gallons The only coolant approved for these engines; premix avoids mixing errors. | Parts | shop |
| Distilled water 1 gallon For topping off and for mixing if you buy concentrate. | Consumables | shop |
| Replacement hose clamp Worm-gear clamp sized for lower radiator hose Optional replacement if the factory spring clamp is weak or you want easier future service. | Parts | shop |
| Nitrile gloves and safety glasses Hot coolant is under pressure and glycol is toxic to skin and pets. | Safety | shop |
| Torque wrench 1/4 or 3/8 in drive, 5-25 ft-lb range For reinstalling the air dam and shield fasteners without stripping plastic. | Recommended | shop |
Tool sizes are identical for the 4.3 LV3, 5.3 L83 and 6.2 L86 - same radiator, surge tank and lower hose layout. Only capacity differs: figure about 12.5 quarts total for the 4.3 V6 and roughly 13-14.5 quarts for the 5.3 and 6.2, with more on trucks fitted with the Max Trailering / heavy-duty cooling package. Buy 4 gallons of premix to be safe and keep the leftover.
| Radiator drain cock (if equipped) | hand tight only - verify in the service manual |
| Lower radiator hose worm-gear clamp | snug, about 25-35 in-lb - do not crush the hose |
| Front air dam / splash shield bolts | verify in the service manual (approx. 18 in-lb / 2 Nm into plastic) |
| Engine block drain plugs (if removed) | verify in the service manual |
Fastener sizes (7, 8, 10, 13, 15 mm) and the Dex-Cool requirement are solid across the 2014-2018 K2XX range, but drain cock presence varies by build and radiator supplier, so check your lower driver-side radiator corner and verify torque values in the GM service manual.
Some do and some do not, depending on radiator supplier. Look at the lower driver-side corner of the radiator for a small plastic cock; if there is none, remove the lower radiator hose instead.
About 13 quarts total, and roughly 14.5 quarts on a 6.2 L86 or a truck with heavy-duty cooling. A simple drain and refill typically takes 9-11 quarts of 50/50 premix.
Orange Dex-Cool (GM spec, 5-year/150,000-mile extended life). Use premixed 50/50 or mix concentrate with distilled water only, and do not add green or universal coolant.
There is no bleeder screw. Fill with a spill-free funnel on the surge tank, idle the engine with the heater on maximum heat and high fan until the thermostat opens and bubbles stop, let the cooling fans cycle, then set the level to the cold FULL mark and recheck after a drive.