On the K2XX Silverado all three Gen V engines use coil-on-plug ignition, so there are no plug wires to fight. Each coil is held by two 8 mm bolts on top of the valve cover, and the plug underneath takes a 5/8 in (16 mm) plug socket. The front plugs are easy from above; the rearmost plug on each bank is crowded by the firewall, brake booster and steering shaft, and that is where a swivel extension or universal joint saves the day. On 4WD trucks many people find the middle and rear plugs easier through the wheel well with the front wheel and inner fender liner out of the way.
The mistake that costs money is torque. These are aluminum heads with tapered-seat plugs, and cranking them down or working on a warm engine is how threads get pulled. Install the plugs dry, snug them by hand first, and use a torque wrench rather than feel. Also check the gap on every new plug out of the box — they ship close to 0.040 in but shipping bumps happen, and never pry on the iridium center electrode.
| Item | Type | |
|---|---|---|
| Socket wrench set 3/8 in drive ratchet, short and long handle Drives coil bolts, plug socket and fender liner fasteners. | Required | shop |
| 8 mm socket 8 mm, 3/8 in drive (and 1/4 in drive for tight spots) Removes the two ignition coil bolts on each cylinder. | Required | shop |
| Swivel/wobble extension set 3/8 in drive, 3, 6 and 10 in Reaches the angled rear plugs and coils without hitting the firewall. | Required | shop |
| Universal joint 3/8 in drive Lets you break loose the rearmost coil bolts and plugs. | Recommended | shop |
| Spark plug socket 5/8 in (16 mm) thin-wall magnetic or rubber insert, 3/8 in drive Removes and installs the plugs without cracking the insulator. | Required | shop |
| Torque wrench 3/8 in drive, 5-80 ft-lb Sets plug and coil bolt torque in aluminum heads. | Required | shop |
| Spark plug gap gauge Wire-type or feeler gauge covering 0.040 in Verifies gap on new plugs before install; do not pry iridium tips. | Required | shop |
| Trim/panel removal tool Plastic pry set Pops inner fender liner clips if you access plugs from the wheel well. | Recommended | shop |
| 7 mm socket or Phillips driver 7 mm nut driver, 1/4 in drive Removes inner fender liner screws for side access on 4WD/lifted trucks. | Recommended | shop |
| Floor jack and jack stands 2.5 ton minimum Lifts the truck for wheel-well access to the mid and rear plugs. | Required | shop |
| Lug wrench or impact with socket 22 mm socket for most K2XX wheels Removes a front wheel for easier plug access. | Recommended | shop |
| Compressed air or brake cleaner Blows debris out of the plug wells before removal. | Consumables | shop |
| Dielectric grease Small tube Small dab inside the coil boot to prevent sticking and arcing. | Consumables | shop |
| Anti-seize Nickel-based, optional and used sparingly GM says install dry; if used, apply a trace and reduce torque. | Consumables | shop |
| Spark plugs 5.3 L83 / 6.2 L86: ACDelco 41-114 (8); 4.3 LV3: ACDelco 41-114 (6), gap 0.040 in The replacement plugs; confirm part number against your VIN. | Parts | shop |
| Nitrile gloves and safety glasses Keeps debris and oil off you while working over hot aluminum heads. | Safety | shop |
Tool sizes are the same across the 4.3 LV3, 5.3 L83 and 6.2 L86: 8 mm coil bolts and a 5/8 in plug socket. The only differences are plug count (6 on the V6, 8 on the V8s) and access — the V6's rear plugs sit deeper under the cowl, while the 6.2 in a lifted Z71 or High Country is usually easiest from the wheel well.
| Spark plug in aluminum head (new plug, dry) | 15 ft-lb (20 Nm) — verify in the service manual |
| Ignition coil mounting bolts (8 mm head) | 89 in-lb (10 Nm) — verify in the service manual |
| Front wheel lug nuts | 140 ft-lb (190 Nm) |
Coil bolts are 8 mm and the plugs take a 5/8 in (16 mm) plug socket across all K2XX Gen V engines (4.3 LV3, 5.3 L83, 6.2 L86); confirm the exact plug part number and torque figure against your VIN and the GM service manual before you start.
A 5/8 in (16 mm) thin-wall spark plug socket on a 3/8 in drive, plus an 8 mm socket for the two ignition coil bolts on each cylinder. Swivel or wobble extensions are effectively required for the rear plugs.
GM's interval for the iridium plugs on these Gen V engines is about 97,500 miles. Trucks that tow heavily, idle a lot, or run aftermarket tunes often benefit from replacement closer to 60,000-70,000 miles.
The ACDelco plugs come pre-gapped at 0.040 in, which is the spec. Torque is light because of the aluminum heads — roughly 15 ft-lb (20 Nm) dry; verify the exact figure in the service manual for your engine.
Not on a stock 2WD — you can usually get all of them from above with swivel extensions. On 4WD, Z71 and lifted trucks, pulling a front wheel and the inner fender liner makes the middle and rear plugs much easier and reduces the risk of cross-threading.