Spark Plug Change 07 Jeep Grand Cherokee WK (5.7L shown)
This might apply to 06-09 though I'm not positive.
5/10 -- takes patience but the learning curve is steep, you get 16 chances to do it right!
2-4 hours depending on your familiarity with the jeep and your patience
$30-50 for the plugs + $5 for dielectric grease, tools are additional
Compare that to your dealer or mechanic who will probably quote 2-3hrs labor + parts = ~$200-400
I looked high and low for a one-stop-how-to on changing the spark plugs and found only one on a WK info site with no real pictures (http://www.wkjeeps.com/wk_sparkplugs.htm
) I referenced his work and some member info here while changing the plugs and thought I'd pay it forward for anyone else wondering how to do it.
- Torque wrench (12-14lbs needed, do not exceed 15ft/lbs) - one from advance auto was $50 but was shit, will be replacing with craftsman
- Socket wrench
- 10mm socket head
- angle adapter
- Two 3" drive extensions (wobble or I prefer using an angle adapter between two normal 3" extensions.
- 10" or 6" drive extension also comes in handy
- Magnetic or Rubber gasket Spark plug socket (5/8")
- 16 spark plugs (for the 07 WK 5.7L use Champion 570 (OEM P/N SPRE14MCC4) I paid about $35 with tax (7%) for all 16.
- Slotted (flat head) screwdriver (helps to push in the safety tab to get the wires off the ignition coils)
- Compressed air (I used canister air)
- Silicone lubricant (optional)
- Dielectric grease
- Gloves, towels, etc
You DO NOT need anti-seize for the Champion copper core plugs, Champion expressly states this, their plugs are coated already.
For the uninitiated among us, make sure your socket wrench, torque wrench, driver extensions and socket heads are ALL the same size (i.e. 3/8" being the most popular, or 1/2")
You'll need a specially-suited spark plug socket that has either a rubber gasket or magnet to hold your plug so it doesn't drop into the hole AND so that it's easier to pull out the spent ones. You'll see the one I got from advance auto actually has a magnetic ring inside. IMO it works 10x better than the rubber ring and lets you know when you've backed it all the way out of the socket (because it comes free).
You may also want to drape an old towel over whichever side of the car you're working on to prevent scratches. A piece of cardboard on the engine also serves as a handy ghetto tool tray!
First make sure the engine is COOL and remove your dumb engine cover by removing the oil cap and popping the cover off and replacing the oil cap.
You may need to disconnect the hose attached to your CAI at the throttle body to access the plugs better on the right side (ive got an AFE CAI and had to remove mine)
Locate your ignition coils, there are 4 per side (one per cylinder) running parallel to the engine, each coil box has TWO coils, one for each of the two spark plugs per cylinder (hence, the total of 16 plugs). Some are easier to get to an others, some require the wobble/angle adapters or a longer extension and the 2nd forward from the firewall on either side has a wire router on top of it that should be removed (lift the security snaps up with a slotted screwdriver).
Now that you've located them, introduced yourself and got friendly, you want to use some of your air to blow the area around the base to get rid of any loose dirt/dust. Then unclip the wire connector on top of each of the coils, you shouldn't have a hard time reconnecting the right ones because as you'll see they run sequentially and are wired into a wire bundle strapped to the engine and have only enough play go be routed to the coil you're working on.
Pictured: remove the hose from your CAI if necessary, in my case it was.
You want to push in the tab (finger or flat head screwdriver) while lifting up, very easy. The other arrows illustrate the cable guide I mentioned, which needs to be removed to access the nuts holding this in.
Use your 10mm socket head to unscrew the two screws per coil. Some will say these are retained in the housing....that's a LIE!! If you unscrew too far they WILL come out and fall into your engine bay and wind up costing you 30 minutes of fishing your meaty hands into the small spaces to retrieve it.
Once the bolts are loosened, lift up (some require more force) until both of the seals on the two coils pop and release, you can lift one side at a time to leverage the other side if you prefer. Once you get them loose, STOP and spray some more air to clear the dust that was under the housing before removing them.
Apparently you have to be 18 to buy this stuff. That's what happens when they outlaw all the good stuff, kids are forced to get high on AIR!!
With the coil pack out, this is what it will look like, your spark plugs are hiding about 3" down in those holes.
This is a damn fine invention, the magnetic ring inside sure beats the rubber gasket. And dont tell me rubber is better for the plug, just dont JAM OWN IT and you'll be ok.
Using whatever combo of angle adapters and extensions you need (or don't) remove the spark plugs, it's easier to start with the racket, remove the extension and twist it out by hand. That's my old vs. new plugs. Note, no fouling or anything of concern, just worn plugs.
Take a look at some examples of fouled plugs here, if you encounter these you may need to take your Jeep in for service:
The 07 WK 5.7L calls for a 0.045" gap, use the spacer to get to your required spacing on the plug head.
Apply the dielectric grease to both the ceramic end of the plug and the inside of the spark plug coil. This serves as an insulator to the electric current and prevents loss of energy, it also helps keep out moisture. You can use this on your light plugs too.
Note, the top one has too much grease.
End of the coils with some dielectric grease.
Place your now-ready plug into your 5/8" spark plug socket and carefully lower it back in. Don't use your ratchet, simply tighten by hand to start for each one to ensure you do not cross-thread the spark plugs.
Once hand tightened, set your torque wrench to the appropriate ft/lb setting and lock the handle. This cheap POS's lock broke within the first use. NOT ADVISED.
For the jeep in question the settings call for 12-14ft/lbs not to exceed 15ft/lb
I spray just a wittle bit of silicone lube onto the base of the coils to help with removal next time, it also helps to create a water-tight seal. (wipe them down first)
After lubing, place the coils back into the holes the same way they came out and push down. Mine had no "pop" or lock but once pushed all the way down they're in. Then tighten each of the two bolts back down and reconnect the wiring harness.
Apparently in my haste i snapped one of the security locks that keeps it in place. After some jiggling and contemplating I decided it was too loose, so I fashioned a harness to keep it in place until I can forget about it.
You can do one bank (side) at a time if you feel comfortable with it, or do one coil pack at a time. Doing each bank will save a LOT of time (by half almost) just be sure to keep the area clear of dust and debris.
After plugging them all back in, fire up the jeep. If it fires up you're golden, if not dont panic! Go back and check each of the spark plug harnesses to ensure they're tightly clicked back into the coil packs.
Any questions or clarification needed, feel free to ask!
THAT'S ALL FOLKS!