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Tips before changing the spark plugs...

78K views 32 replies 26 participants last post by  HemifeverAZ 
#1 ·
Many thanks to BrilliantBlackHemi and his photo-article on changing spark plugs. When the dealer asked me $230 dollars to do it once, I decided to evaluate my cost to purchase new tools and replacement parts over 4 spark plug service intervals. That's $220 for the next 200,000 km for me. Versus them at $920. $700 anticipated savings.

I completed the 16 plug job last night with success, including setting each one to the right torque.

However there are some important prerequisites I needed to assess before deciding to go ahead with that job, but they aren't mentionned in that article, so I thought I would write this.

It's because taking out spark plugs is the same as open-heart surgery, in the sense that you are exposing the innards that are not designed to be exposed to the elements.

And you have to be confident that you can sew up the patient completely, otherwise you may kill it. That means preventing disasters like cross-threading, introducing contaminated particles that may have wound up on your plugs, cracking the old plug, etc.). So even if you are under warranty, you are assuming these risks.

Before starting, as stated in the service manual, you need to prevent ANY particles from entering into the engine!

Here are the precautions I took, being outdoors initially:
- blast the engine with a vaccuum cleaner hooked up backwards and let the dust settle.
- keep the combustion chamber exposed to a minimum by preparing the new spark plug before taking an old one out.
- wait for a calm day (because there's no way I'm letting a windy day push around dust/dirt/leaves/bugs that could wind up in the compression chamber)
- keep the tools clean (imagine rust particles from old tools winding up you know where)
- work on a thermally static (cold) engine

One other helpful hint regarding the removal of the spark plug boot/coil pack is this: when they say "Remove coil pack by pulling upwards", they really mean "away from the engine along the axis that is perpendicular to the engine", or if you prefer "about 45 degrees relative to the ground". Not 90 degrees to the ground, which is what "upward" usually means...
 
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#7 ·
I too don't want to pay $200.00 bucks for what is a a relatively easy job. My mechanic says the cost is due to the Upper Intake Manifold Cover. Is that the 'boot'?

I'm driving the Magnum for its aesthetics, not performance, so I have the 2.7 SE

Thanks anyone!
The Hemi's have 16 plugs (2 per cylinder). I'm at 60,000 miles and having the dealer do them tomorrow!
 
#8 ·
I too don't want to pay $200.00 bucks for what is a a relatively easy job. My mechanic says the cost is due to the Upper Intake Manifold Cover. Is that the 'boot'?

I'm driving the Magnum for its aesthetics, not performance, so I have the 2.7 SE

Thanks anyone!
the upper intake manifold has to be removed to access the spark plugs on 2.7L and 3.5L. it is not nearly as easy as 5.7L or 6.1L.
 
#9 ·
Is the 3.5 different than an LH car?

I don't have to take the upper plenum off my LHS to change plugs!

A vacume hose helps with the plugs as well ,but thats ******* enginering!

How? put the plug in the hose lower it down the tube and thread it in by hand less chance of cross threading when you can feel it by hand,then pull the hose off and use the wrench!

I'd bet it's more than 2 hours if you replace the plug wires too!
 
#10 ·
Is the 3.5 different than an LH car?

I don't have to take the upper plenum off my LHS to change plugs!

A vacume hose helps with the plugs as well ,but thats ******* enginering!

How? put the plug in the hose lower it down the tube and thread it in by hand less chance of cross threading when you can feel it by hand,then pull the hose off and use the wrench!

I'd bet it's more than 2 hours if you replace the plug wires too!
intake manifold is completely different than LH.
 
#12 ·
plug wires...there are no plug wires on the 5.7s...just coil packs directly connected by boots to the plugs. Changing plugs is one of the easiest jobs...yes sometime manifolds can be in the way...but if you have the right tools, the job is much simpler,i did all my plugs (16 of them)..and gapped them all in about 1 to 1.5 hrs. 1/2" socket drive,6" extension and 5/8" deep plug socket,and a universal joint, i believe a 10mm socket for the coil packs,and a gapping tool. i used the 6" extention with the 5/8" socket(which has a rubber boot inside to hold the plug) and started threding it by hand then used the wrench to finish.
 
#13 ·
Just changed plugs on my 300/3.5.l The top section (plenum) was difficult to maneuver to get access to the back plugs, but I disengaged a metal pipe off the plenum. When I put the whole rig back together, it ran extremely rough. Turns out the pipe came loose and this was resolved when I maneuvered the pipe back into the plenum. Does anyone know what this pipe does and any suggestions on how to seal it. It appears to be fine, but I'm showing an "check engine" light.
 
#15 ·
Just changed plugs on my 300/3.5.l The top section (plenum) was difficult to maneuver to get access to the back plugs, but I disengaged a metal pipe off the plenum. When I put the whole rig back together, it ran extremely rough. Turns out the pipe came loose and this was resolved when I maneuvered the pipe back into the plenum. Does anyone know what this pipe does and any suggestions on how to seal it. It appears to be fine, but I'm showing an "check engine" light.
I haven't done the plugs in my 3.5L yet, but from what I've read you're talking about the EGR pipe. From what I remember, you're supposed to change the O-rings that seal the EGR tube at the lower end, every time the upper intake manifold is taken off.

The "check engine" light was turned on by the vacuum leak created when you left the tube off. If you managed to seal it back up, you probably can clear the code by pulling the neg battery terminal off for 15? minutes, or it might shut itself off after a certain number of start/stops. (As long as the tube is really sealed.)

srg
 
#14 ·
I have plenty of plug wires on my 5.7 . They run across my intake manifold. Sept. 04 build date.
 
#19 ·
I'm gonna try -10 psi . Gotta tone my car down, damn thing is a beast and I'm running a custom 87 octane and it's still a handful in winter. 7 months, that's about how long our winters are in Maine. Yup, gonna drop a couple Valium in the gas, that can't hurt.:wink: Got some swamp land for sale too.
 
#20 ·
Just changed the plugs on my 5.7. By far the easiest spark plug replacement job ever. A few suggestions. I noticed the service manual requires a little di-electric grease on the the plug boot and coil oring. Use a pen screwdriver to apply a little di-electric grease to the inside edge of the spark plug boot and to the top edge of the valvecover opening (where the coil oring rest against). Also, I'm not a big fan of using the spark plug socket to install plugs (too easy to cross thread). I apply a little antisieze to the plug threads and attach a long piece of vacuum hose to the top of the plug. I then grab on to the vaccuum hose, lower the new plug into the hole and spin away until the plug is seated. Then I use the spark plug socket attached to an extension and torque wrench to finish tightening the the plug.
 
#22 · (Edited)
I changed the plugs on my 3.5L 300, I took my time and went real slow to make sure of no damage, I had to do it twice as I used after market plugs and the car did not like it, so tip number one use the stock
plugs. I changed the intake gasket and the EGR tube gasket as well to make sure no leaks. The process is simple but can seem a little hard so take your time.

1. Disconnect your battery neg connection in trunk, (Leave the trunk open because its battery operated and you will need to go thru the back seat if you close the trunk)
2. 10 mm socket with extentions and 10 mm wench.
3. 15 mm socket and wench
4. Torque wench (make sure its IN POUNDS, not FT POUNDS) I bought a 20 dollar wench at Harbor Freight.
5. Air Plenum intake gasket (7 bucks)
6. EGR tube gasket.
7. Anti lock goop for spark plug theads.
8. Plug Boot goop.

Start but removing the air box tube, next remove the 10 mm bolts on the throttle body and the 2 brackets on passenger side and put them somewhere safe. Next loosen the 15 mm bolts holding those brackets
you do not need to remove them just need movement so you can get the brackets off the mountings.

Next remove the vacuum hoses on the back of the plenum, and disconnect the electrical connectors, they have different types of locks on them they are red and you pull the lock up to unlock them.

Next using your 10 mm socket loosen the air plenum bolts, they do not come out they only disengage you can tell buy pulling up on them and there will be some movement. Pull up on the plenum
and it should rise off the intake manifold. As the plenum comes up gently pull the EGR tube out of the back, hang the plenum up using bungy cords so you can work. Someone here posted pictures of
this in the magnum thread. Make sure you do not bent the EGR tube as you do this, just go slow.

Next remove the one screw holding the coil over the spark plug and pull the coil up and off the plug (do 1 at a time) go slow and be careful with the plug wall, remove, gap, grease and replace each
plug and coil boot. The last back plug on the passenger side is the hardest but you should have enough room to get at it. I put the socket with extension in first then connected the socket wench disconnected
the plug took the socket wench off and pulled the plug out. Then just reverse it to put it back in.

Next I pulled the air plenum gasket off and put the new on and placed the air plenum back on the intake manifold (as I did this I replaced the EGR tube gasket and put it back in the air plenum)
once I was sure it fit right I hand tighten the air plenum bolts down. Make sure your EGR tube is in and snug before tighten bolts. Use your IN POUNDS torque wench and set it to 105 IN-PDS and
start the torque process doing each bolt starting from the middle of plenum and moving outwards until torque is reached.

Now you reconnect electrical connectors and bolts in reverse and your done. Now have a beer.
 
#23 ·
Any tips or clues to get the EGR gasket to seat correctly. I keep getting leaks from back there. I don't have any reference to how the gasket should sit on the pipe to make sure I got it right. Kinda figured it would just sort itself out under pressure when pushing it back into the plenum, but no.
 
#24 ·
Ok so I'm at 30 k on my scat pack , says I should change plugs . Really ? Engine runs fine . I have the automatic with the mds system . When I was looking fo plugs , it said something about the coil over boot ? What is that and do I need to change those also? Dealer wants to charge me. 555 bucks just to change plugs . 16 of them . Why so much ? And can I comply with warranty if I do it myself or have my ASC certified mechanic do it ? Why the big deal on these plugs ? Hell I got 100,000 on my ford truck.

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#30 ·
555 dollars just to change the plugs is ridiculous , 35 dollars a plug ? Crazy . And you don't have to take it to dealer to service plugs , a ASE certified mechanic can do it and not void your warranty , if make sure that I got a receipt that said how many miles etc etc . Toys are expensive and not sure if super plugs will do any better ?? Anyone try it ? Let me know .

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