Spark Plug Replacement Cost: Parts, Labor, and Real-World Ranges

A misfire, rough idle, or sluggish acceleration often points to tired plugs—and the bill can range widely. Spark plug replacement cost has two components: parts and labor. Parts depend on the plug material your engine calls for; labor depends on how buried the plugs are. On many late-model engines, removing intake pieces or coil packs dominates the job time, so two cars with identical plugs may have very different totals. 

It helps to ground the conversation in current market numbers. Across popular models, professional replacement commonly lands between the mid-$100s and the mid-$700s depending on access and cylinder count. Economy sedans sit near the bottom of that range; V6/V8 crossovers and minivans trend higher because of intake and cowl access. 

How Much Does Spark Plug Replacement Cost?

For a typical modern vehicle at a repair shop, expect roughly $260–$390 on average nationwide, with parts around $80–$120 and labor making up the rest. Compact sedans can come in closer to $140–$260; certain transverse V6s and hybrids land near $250–$360; large V6 SUVs can reach $500+ when rear-bank access is time-consuming. These are fair-price ranges, not worst-case quotes. 

DIY changes slash labor to zero, leaving only the plugs themselves. And if you have an older car, you can get the copper spark plugs for a very low price and they work just fine.

What do Engine Plugs in Your Car Actually Cost by Material?

If you’re pricing parts for a DIY job, plan roughly:

• Copper: ~$3–$5 each, typically short life (although they can last 50,000 miles or more).
• Single-platinum: ~$6–$10 each, extended life.
• Iridium: ~$8–$30 each, OE on many modern engines.
• Ruthenium: typically mid-teens per plug, positioned as a high-ignitability, long-life option.

Actual prices hinge on thread size, heat range, and brand, but these ballparks reflect current retail shelves. 

Why the Price Swings From Car to Car?

Three variables dominate.

Access and Labor Time

On many late-model engines, the intake plenum or upper cowl has to come off. That can push an otherwise simple tune-up into multi-hour labor. It’s why some mainstream V6s cost far more than four-cylinders using the same plugs.

Cylinder Count and Plug Count

More cylinders mean more plugs. Some engines also use two plugs per cylinder—Chrysler’s HEMI is the famous example—so a 5.7L V8 needs 16 plugs, doubling the parts bill and adding time. 

Specified Plug Material

Many modern engines require iridium or ruthenium for stable spark under lean burn and turbo heat. Using the correct OE-equivalent material protects coil packs and helps keep long service intervals intact. 

Tip: Before you shop, look up the exact plug part number your engine requires; mixing materials across cylinders is a bad idea and can create uneven ignition energy. (Your owner’s manual or a reputable parts catalog has the spec.)

Example: What a Jeep Grand Cherokee Owner Might See for Spark Plug Replacement

A Grand Cherokee’s spark plug replacement cost varies with the engine. For late-model years, fair-price estimates often fall roughly in the $400–$630 range at a shop. If you own the 5.7L HEMI, remember it uses 16 plugs; parts alone can approach double the cost of an eight-plug V8, even before labor. 

The dual-plug layout isn’t a mistake—firing two flame kernels speeds combustion in the HEMI’s chamber and helps emissions and efficiency. The trade-off is more parts to buy when service time arrives. 

How Long Do Spark Plugs Last, and When Should You Change Them?

Iridium and ruthenium plugs are designed for long intervals. In real-world use, it’s common to see 60,000–100,000 miles on iridium, assuming a healthy engine and no oil burning. Many makers list ~100,000 miles in maintenance schedules; severe service (short trips, dusty environments, modified engines) justifies sooner. If you’re chasing a misfire, don’t wait on schedule—address it immediately. 

Common prompts to check plugs include extended crank, rough idle, loss of fuel economy, and load-dependent misfires. Rule out coil and injector issues as you diagnose; a scan for misfire counters and plug inspection will tell the story. 

Plug Replacement: DIY vs. Hiring a Pro

If your engine bay offers straightforward access, DIY can be a satisfying afternoon—just keep it methodical. Here’s a safe, no-drama approach:

Tools

• 3/8-in. ratchet
• Extensions
• Spark-plug socket with rubber insert
• Small torque wrench
• Dielectric grease
• Anti-seize only if explicitly called for by the plug maker
• Compressed air

Steps

1. Work cold: heat expands aluminum heads and increases thread damage risk.
2. Label coils/wires: unplug coils (or wires) one at a time to avoid mix-ups.
3. Blow out wells: remove grit before unthreading plugs.
4. Break free and remove: keep the socket square; if a plug feels stuck, work it back and forth gently.
5. Check gap only if required: many precious-metal plugs are pre-gapped and fragile; follow the box note.
6. Thread by hand: spin the new plug by fingers at least 5–6 turns to confirm no cross-threading.
7. Torque to spec: over-tightening cracks insulators and damages threads; under-tightening can cause blow-by.
8. Apply a small dab of dielectric grease inside each boot: reinstall coils/wires and confirm snug clicks. 

Warning: Some applications (certain V6s/V8s) hide rear plugs under the cowl or intake. If you can’t see a clean path for your tools, pay a pro—the labor is cheaper than repairing a broken plug or damaged threads. 

Cost to Replace Plugs and Wires

Many late-model engines use coil-on-plug ignition and have no traditional high-tension wires; they do have inexpensive coil boots/insulators that can harden or split. If your vehicle still uses plug wires, professional replacement typically falls around $250–$335 including parts and labor. On coil-on-plug engines, budget a few dollars per boot if you’re refreshing them during a plug service. 

Tip: Whether you have wires or boots, inspect for oil in the plug tubes. Valve-cover leaks contaminate boots and cause chronic misfires; fixing the leak alongside the plug service saves repeat labor.

When a High Quote is Justified

Sticker shock usually traces back to access, dual-plug engines, or bundled maintenance. A transverse V6 in a crossover where the rear bank sits under the cowl can require several hours just to reach plugs; a hybrid may demand extra steps around high-voltage safety. That’s how an SUV’s spark plug replacement cost can climb into the $500–$750 bracket with labor dominating. 

Bottom Line on Value

Treat plugs as precision components, not commodities. Using the correct material and heat range, torqued correctly, preserves coils and catalysts and restores crisp throttle response. If you’re price-shopping, compare like-for-like (material and access) and decide whether your time and tool access make DIY attractive—or whether paying for the right labor is the better investment this time around.