DIY Ignition Coil Replacement: Tools, Steps, Torque Specs & Savings
COP coil replacement on a 4-cylinder is one of the most beginner-friendly engine jobs you can do. 10mm socket, 10 minutes per coil. This guide covers the full procedure including the torque specs most shops skip.
DIY Savings at 2026 Labour Rates
Single 4-cyl coil
$60-$100
4-cyl full set (4 coils)
$100-$200
V6 full set (front bank)
$130-$220
V6 full set (with rear bank)
$200-$340
V8 full set (5.0 Coyote)
$200-$400
V8 5.4L Triton (no plug break)
$300-$500
Difficulty by Engine Type
| Engine type | Difficulty | Time per coil | Saving |
|---|---|---|---|
| 4-cyl inline COP (Civic, Corolla, Camry 4-cyl) | Easy | 10 min/coil | $15-$25 per coil |
| V8 front bank (5.0 Coyote, 5.3 LS front 4) | Easy | 15 min/coil | $18-$35 per coil |
| V8 rear bank (Coyote/LS rear 4) | Moderate | 25-35 min/coil | $35-$60 per coil |
| V6 transverse front bank | Easy-Moderate | 15 min/coil | $18-$30 per coil |
| V6 transverse rear bank (intake off) | Moderate | 45-60 min for all 3 | $65-$120 for all 3 |
| EcoBoost 3.5L / 2.7L | Moderate | 20-30 min/coil | $25-$50 per coil |
| Subaru flat-4 / flat-6 | Moderate | 20 min/coil | $20-$40 per coil |
| 5.4L Triton 3V | High risk | 15-30 min + plug risk | Risk of extra cost if plug breaks |
| Coil pack with wiring fault | Leave it | N/A | N/A |
Tools Required
Required for most COP installs
- 10mm socket + short 3" extension + 3/8" ratchet ($25-$45 from a basic set)
- Trim removal tool for plastic clips on engine cover ($8)
- Dielectric grease tube ($5, lasts for years)
- OBD-II scanner to clear codes after ($45-$120)
For V6 rear bank or EcoBoost
- Long 1/4" extension ($10)
- Swivel / wobble socket ($8)
- Intake manifold gasket if reusing the old one ($12-$30)
- Torque wrench 1/4" or 3/8" drive ($35-$80)
Total from zero: $80-$160. If you own a basic tool kit: $20-$60 incremental. AutoZone/O'Reilly/Advance loan torque wrenches free with deposit.
8-Step COP Replacement Procedure
Prepare safely
Park on level ground with engine off and cool (30+ minutes after last run). Disconnect the negative battery terminal.
Remove engine cover
Remove plastic engine cover if present (plastic clips or 4-6 bolts).
Unplug electrical connector
Press the release tab on the electrical connector and pull straight up. Do not pull on the wires.
Remove hold-down bolt
Remove the single 10mm hold-down bolt. Pull the coil straight up and out by gripping the coil body, NOT the boot.
Inspect the well
Inspect the spark plug well for oil. Oil contamination means the valve cover gasket is leaking and must be addressed.
Install new coil
Apply a pea-sized amount of dielectric grease inside the new coil boot. Insert straight down. Press firmly until fully seated on the spark plug.
Torque and reassemble
Reinstall the hold-down bolt and torque to spec (typically 7-9 ft-lb on Honda/Toyota; 89 in-lb on Ford/GM). Reconnect the electrical connector until it clicks. Reattach the engine cover and battery.
Clear codes and verify
Use an OBD-II scanner to clear codes. Start the engine and verify smooth operation.
Torque Specs
Always confirm in the factory service manual. Over-torquing cracks the coil casing or strips threads in the aluminum head.
| Engine family | Hold-down bolt torque |
|---|---|
| Honda 4-cyl (R18, R20, L15) | 7-9 ft-lb (84-108 in-lb) |
| Toyota 4-cyl + V6 (2AR, 2GR) | 8-10 ft-lb |
| Ford 4-cyl + V8 (Duratec, Coyote) | 89 in-lb (7.4 ft-lb) |
| Ford 5.4L Triton 3V | 89 in-lb (7.4 ft-lb) |
| GM LS V8 + Ecotec 4-cyl | 89 in-lb (7.4 ft-lb) |
| BMW N52, N55, B58 | 7 Nm (5.2 ft-lb) |
| Subaru EJ / FB / FA | 8 Nm (5.9 ft-lb) |
Common DIY Mistakes
Skipping dielectric grease
Boot welds to plug. Next removal tears the boot, adding $20-$50 to the job.
Over-torquing the hold-down bolt
Cracks the coil casing or strips threads in the aluminum head. Head thread repair: $200-$600.
Reinstalling on oil-fouled wells
New coil fails in 6-12 months. Fix the valve cover gasket first.
Not clearing codes after replacement
CEL stays on for 1-2 drive cycles. Car runs fine but owner thinks the repair failed.
Buying no-name coils to save $25
Fail at 25-40k mi. You pay the labour twice.
Pulling on the boot instead of the coil body
Tears the boot. Replacement boots are $15-$30 per cylinder.