What to Know About Changing a Spark Plug
Changing spark plugs is basic DIY car maintenance that can save you hundreds of dollars in labor. A new set of spark plugs can improve engine performance and fuel economy while lowering emission levels. Spark plug removal tools make installing new spark plugs easier, especially when the plugs are in hard-to-reach areas.
Before purchasing spark plug removal tools, check your owner’s manual or local parts store to learn what size spark plugs and the kind of ignition system your car has.
Coil Over Plug ignition systems do not use spark plug wires. On some V-6 engines the intake manifold may have to be removed to replace the spark plugs. Leave that to a pro. However, if you can access the rear cylinder head, with the right tools you can do this job yourself.
These are the tools you’ll need to replace your spark plugs. All sockets and ratchets listed are 3/8-in. drive:
- Spark plug gap gauge: Correctly sets the “gap” between a spark plug’s side and center electrodes to the manufacturer’s specifications.
- Needle-nose spark plug pliers: Removes spark plug wire boots in tight places. Pliers with serrated jaws lessen the chance of damaging a spark plug wire.
- Spark plug wire pliers/pullers: Remove hard-to-reach spark plug wires while providing more protection for the wire boot. These pliers come in two designs, straight or offset (angled). Look for sturdy jaws and handles that are insulated and won’t twist.
- Spark plug sockets: These feature a rubber boot or magnet to hold a spark plug in place while removing or installing. They also protect the porcelain insulator. Spark plug sockets have thinner walls than a standard socket. They come with a hex head on the back end so you can turn with a wrench if you cannot use a ratchet or swivel extension to reach the plug. Many come with large markings to easily identify the socket size. A knurled non-slip surface machined into the outside of the socket offers a better grip to help you start spark plug threads by hand.
- Six-point vs. 12-point sockets. Spark plug sockets usually are six-point to prevent rounding off spark plugs that are tough to remove. Some newer imports need extra-thin-walled 12-point sockets to reach spark plugs hidden in tight corners.
- Swivel (universal or flex-head) spark plug sockets have a flexible joint to reach around obstacles or get to spark plugs deep in the engine bay. Look for swivel sockets with a built-in extension that helps access difficult-to-reach spark plugs.
- Ratchet wrench: Available in assorted drive sizes (most common are 1/4-in., 3/8-in. and 1/2-in.) and configurations (short, standard, long-handled and flex-head). For removing spark plugs, a longer handle flex-head ratchet is the way to go, but a standard ratchet will work just fine. Ratchets with 72 teeth work better in confined spaces. “Quick release” models make removing sockets easier when your hands are greasy.
- Torque wrench: This tool should be your go-to for tightening spark plugs, especially in cast aluminum cylinder heads. Although a flex-head torque wrench is best for installing spark plugs, a fixed-head torque wrench will also work. Look for a “click” style torque wrench that can be felt as well as heard when the proper torque is reached. These all-metal, reversible wrenches are also easy to adjust and read standard and metric scales.
Best Spark Plug Gap Gauge
The one-piece, zinc alloy Weewooday Spark Plug Gap Gauge fits the bill nicely. Like most spark plug gap gauges, this simple tool has standard readings on one side and metric on the other side.
Best Needle-Nose (Hose Ring) Spark Plug Pliers
The QWOKR Spark Plug Wire Removal Pliers feature serrated jaws and a sturdy non-slip handle. They provide a firm grip and good leverage when removing stubborn spark plug wires, especially on vehicles with heat shields that cover just about the entire spark plug wire boot.
Offset Spark Plug Wire Pliers
The ARES 70053 Spark Plug Pliers Boot Removal Tool makes removing stubborn plug wires trouble-free. The insulated jaws firmly grasp the boot to protect it when twisting the spark plug wire. The spring release and angled head of this rugged puller let year reach wires hidden behind other engine parts, making it a must-have for the DIYer.
Best Standard Spark Plug Wire Pliers
The Lisle 52990 Spark Plug Pliers earned a 4.5-star rating on Amazon with more than 2,300 reviews.
According to the manufacturer, the specially shaped jaws grab the spark plug wire boot straight on or from the side. This makes these pliers exceptionally useful when removing spark plug boots that seem to have “welded” themselves onto the spark plugs.
Best Spark Plug Socket(s)
If you’re buying a spark plug socket for one size spark plug (usually 5/8-in. or 13/16-in.) the thin-walled Ares 11020 5/8-in. or companion Ares 11019 13/16-in. 3/8-in. drive magnetic spark plug sockets are an excellent choice. However, if you’re working on multiple vehicles, the ARES 11016-Five-Piece Magnetic Spark Plug Socket Set is the way to go.
All sockets come with strong magnets and all the features previously listed. In addition to the 5/8-in. and 13/16-in. sockets, this five-piece set comes with 9/16-in. six-point and 14- and 16-mm 12-point sockets. The included rail keeps the sockets neatly organized. A lifetime warranty makes these sockets a worthwhile investment.
Best Value Spark Plug Socket(s)
If you rarely use a spark plug socket, the Craftsman CMMT43324 5/8-in. or Craftsman CMMT43325 13/16-in. 3/8-in.-drive spark plug sockets are a good choice and a great value. Their rubber insert tightly holds and protects the spark plug. Craftsman’s lifetime warranty make these a good option for a beginner.
Best Swivel (Universal/Flex-Head) Spark Plug Socket
If you can’t get a straight shot at a spark plug, the Gearwrench 80546 3/8-in.-Drive Six-Point 5/8-in. x Six-Inch Magnetic Swivel Spark Plug Socket is the one you need. With more than 5,400 reviews and a 4.8-star rating on Amazon, this socket is a clear winner. The six-inch attached extension with a handy knurled band keeps you from busting your knuckles. This socket has all the features you need, plus a limited lifetime warranty.
Best Drive Ratchet Wrenches
You can’t go wrong with a Craftsman 3/8-in.-Drive CMMT81748 Ratchet Wrench.
With 72 teeth, this standard length (7-1/2-in.) quick-release ratchet needs minimal movement to grab the next tooth — a helpful feature in tight quarters. The longer 11-1/4-in. handle of the Crescent CRW10 3/8-in. Drive Flex-Head Ratchet gives you greater leverage. The flex head allows you to reach spark plugs in awkward spaces from different angles.
Best Torque Wrench
The medium-duty (10 to 80 ft.-lb.) Tekton 3/8-in.-Drive Click Torque Wrench should be your go-to tool for confidently tightening spark plugs. This reversing head, dual scale all-metal torque wrench may be the perfect tool for keeping your car running and out of the repair shop.
All prices and links were current as of publication.