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3.3/3.8 Rear Spark Plug Replacement

77K views 32 replies 16 participants last post by  Biopete 
#1 ·
I've read many different ways online to get to the rear spark plugs, in my case on a 1997 Town & Country LXi 3.8L, and I was wondering for those who have replaced them before, What is the best method you have used to reach the rear plugs? And also, any instructions or links to websites would be helpful, it looks like one of the hardest spark plug jobs I've ever seen.:jpshakehe
 
#3 · (Edited)
I did mine from down under a year ago with the van on a lift.

From what i seen when taking my engine apart i would definatley do it from the top if i ever do it again.
Taking the wiper assembly away(easy) and remove the upper intake plenum and you got plenty of room to do it without scratching your hands and arm to pieces.

Even if it means removing some stuff it would go faster that way because of the incredible limited workspace you have from below, it tok me 15 min to get one plug in,the whole job was done in 4 hours if i remember right including to do one plug twice because i managed to break it when installing the new one, it was incredible tiresome to be underneath with your arms over your head all the time. From the top i'll think i could be finished in about 1- 1 1/2 hour.
 
#4 ·
I did mine from below

There's quite a bit a bit of room in the transmission tunnel, and you can reach up and actually touch the plugs. I had trouble with the "alternator plug" (#6?) , I couldn't reach it from below, and ended up removing the alternator bracket and shoving the alternator back:cry:
 
#6 ·
There's quite a bit a bit of room in the transmission tunnel, and you can reach up and actually touch the plugs. I had trouble with the "alternator plug" (#6?) , I couldn't reach it from below, and ended up removing the alternator bracket and shoving the alternator back:cry:
The alternator plug is #1. With everything removed as I did it, it was very simple, also a very simple way to change the upstream O2 sensor as it was in plain view, though I'd already changed it a few months ago from down under.:nut:
 
#5 ·
Wow, what a job.

Thanks for all of your suggestions and input guys. I ended up doing it from the top end. I removed the hood(not necessary, but sure helped with room and removing the windshield wiper cowl assembly and it was only 4 bolts), removed the windshield wipers/cowl assembly, the intake plenum(the vacuum lines were a little bit of a pain and a few snapped but I got those replaced), had to remove a bracket from the alternator, easy, and the hardest part was just removing the bracket holding a wire harness from the back of the plenum, the bolts were a little hard to get to due to the a/c lines and my big hands i guess, and the bolts were torqued down like crazy, but after they were out the plenum removed with ease and I replaced the back plugs(with champion double platinum RN14PMP5 OEM's) and I replaced the wires with BWD Selects, which I believe are Borg-Warner. They are very good wires. Used anti-seize of course. Mounted the wire harness bracket back, put the plenum(with new gasket), vacuum lines, sensors, and alt.bracket back on then changed out the front ones. Replaced Wipers and Hood and I was good to go, It runs great and what a difference in acceleration these new plugs made. The old ones were alittle worn out. I started the job at 2:30pm and was finished and had it running at 6:00pm. I guess 3.5 hours wasn't too bad for everthing that was removed and it being my first time replacing them. I think if I had a torque wrench and some other air tools, it would have gone by alittle faster. :beerchug:
 
#8 ·
I also went from the top. The first time I paid a mechanic to do it. But my Power steering pump went bad so I had to replace that. And had a O2 sensor that needed to be done too, so I figured I mine as well replace everything I could get my hands on since I knew I was going to be driving the van for at least two more years. Did the power steering pump, Alternator, O2 sensor, plugs and wires.
 
#9 ·
Fighting with the M10 (15 mm head) bolts holding that bracket to the plenum can be avoided if you unfasten the rear harness from the bracket instead, and push out the oxygen sensor plug retainer. That way, you only have to remove the bolt holding the support strut to the head, and disconnect the ground strap at the firewall.
The harness clamps are held to the bracket by hex-head sheetmetal screws. They are hard to reach but aren't tight.
 
#10 ·
I've changed the rears on several 96 - 98s and always rotate the alternator to get the pass side and from below to get the middle and drivers side. I use jack stands and a creeper. Takes me about an hour. Yes it's a PITA but, going from below greatly reduces the chance of spinning a bolt head off or breaking something else in the process of getting to the plugs. No special tools needed.
 
#11 · (Edited)
Aside from the work, it runs great. I didn't really know what kind of performance I was missing out on. :Wow1: The tires have always broke loose from a deadstop WOT but they really let her rip this time leaving a fairly large black mark, with traction control off of course. I think I surprised that teen in that honda. :lol: Here's some pics of the disassembly:





 
#13 ·
Aside from the work, it runs great. I didn't really know what kind of performance I was missing out on. :Wow1:
Here's some pics of the disassembly:
Wow..:blink: Thanks for the pictures, but,...
I have responded to this problem before saying "Take it to a mechanic"
To me this post confirms that conclusion.
Just me.. I would gladly PAY vs. taking all this stuff off.
I do hope you changed the wires too.:nut:
 
#12 ·
Great pics! These are going to be useful to many. I'm sure I'll be using this post as a link in other threads. Thanks. Course you could have avoided all that but, hey if you're bored, have the time, and ignore the nightmare potential, then press on.
 
#14 ·
I, for one, don't know a mechanic whom I'd trust to do this correctly, w/o taking shortcuts, and re-assemble everything exactly the way it was. Also note that removing the intake plenum would be still be necessary for replacing the valve cover gasket on the rear, or the notorious coolant pipes on vans with rear heat.
 
#16 ·
Originally posted by RIP
Great pics! These are going to be useful to many. I'm sure I'll be using this post as a link in other threads. Thanks. Course you could have avoided all that but, hey if you're bored, have the time, and ignore the nightmare potential, then press on.
Thanks, I hoped they would help someone out who was trying the same project.I don't have a lift and I'm not trying it from below on ramps, not high enough. It really wasn't that hard at all, fun for me in fact.

Originally posted by bowen
Wow.. Thanks for the pictures, but,...
I have responded to this problem before saying "Take it to a mechanic"
To me this post confirms that conclusion.
Just me.. I would gladly PAY vs. taking all this stuff off.
I do hope you changed the wires too.
Well, I enjoy working on cars, I'm just a DIYer I guess. It wasn't very difficult at all and was well worth the money saved vs a shop, and of course I replaced the wires. It would be crazy not too. :nut: You can see the new ones in the back in the 3rd picture and all 6 new ones in the 4th picture.

Originally posted by alvin
I, for one, don't know a mechanic whom I'd trust to do this correctly, w/o taking shortcuts, and re-assemble everything exactly the way it was. Also note that removing the intake plenum would be still be necessary for replacing the valve cover gasket on the rear, or the notorious coolant pipes on vans with rear heat.
Same here, I had every bolt back in place and everything done correctly. Deffinately no shortcuts taken here :nut:.

Originally posted by AzTraveller
Is that 2 PCV valves, I see, or just a plastic "EL" adapter. Definitely replace the old one while you're there.
It's just one, the white one at the far end of the picture. The hose was VERY brittle and cracked when i bumped it with the intake so I replaced it and used a plastic elbow so it wouldn't just be a kinked up piece of new hose. The PCV valve was replaced about a month ago and it was easy to get to without disassembling anything.
 
#19 ·
I always say if you want it done right ,,,,,,,,,,,,, DIY
mecahanics may get frustrated crack a plug by mistake, brake some conector and figure what is the wors it could hapen? job security?
to them is another day at the ofice to me it is my car , mine and my families safety and I enjoy it and take pride in it too.
I went tool shopping today, got me an engine crane 2 ton, new welder and mask, old ones broke a long time ago, a small sand blasting gun, some nick nacks, between all this and a junk yard motor I am still $1500 under what an engine swap costs, less a weekend of my time, not counting the strut post repair which I am going to tacle at the same time, speeking of which where do you live? my drivers post rusted through the van is resting on the cowl. not even joking.
what plugs did you use I keep hearing about these platinum deal?
 
#21 ·
I live in Southaven, MS. Memphis,TN(USA) is right above me and about 1 minute away. I used the OEM plugs that came in it from Chrysler, it's what's best for it. They were Champion Double Platinum(RN12PMP5) and you shouldn't use anything but them in my opinion. The plug wires were BWD(borg-warner) Selects.
 
#22 ·
yup, that might explain it, I live in detroit , mi they use a lot of salt here, I got to move, cars do not last very long here, you may have the same manufacturing defect as mine but because of milder climate and less or no salt, in the winter your van is lasting a lot better then it would up here.
 
#23 ·
I guess so, I went out and doubled check to see if there was any and there are no signs of rust at all...top or bottom(from what I could see) of the tower. I guess I'm lucky to live in the south...when we do get snow, they put down sand anyway,not salt. :ThumbsUp:
 
#24 ·
that's what it is, come to think of it the only van i seen with a little rust may be a southern van, only in mich. for the past few years, the kid that owns it is a student here, most vans arround here sit a bit crooked, the owner may not be aware or putting it off, I bet those 1 out of 10 vans are all northern vans, whom else has this issue and where do you live? curious.
 
#25 ·
I live in GA and rarely see rust issues.
The heater lines etc just are not a problem. I suppose it's the salt on the roads?
I think resale values are less with all cars from up north.
I'm seen only a few cars with block heaters in them. One I remember was an old Mercedes.
Do all you Northerners actually "plug in" the engine on cold nights?:biggrin:
 
#28 ·
mannn 30 degrees is a nice day here, I got to wake up at 4 tomorow to plow snow, these block heaters bearely keep them from freezing, they ease startup that's all, keep oil warmish, your heat comes from coolant, you'd still need to warm up the engine.
they are not necesary up here, they are usefull on diesels, for reliability start up, just fancy on gas engines, maybe in alaska they'd be necesary.'
just be thankfull to live in the south I got to get the heck out of here, I've been taking my wipers in the house overnight, otherwise they are worthless, they freze and loose theyr flexibility, worthless in the morning. gass bill was $300 las month how bout that?
 
#29 ·
Just replaced spark plugs and wires for my 1998 Grand Voyager 3.8 along with rear valve cover gasket. It had125K miles and were on factory plugs. Attacked it from the top. I didn't follow these steps in these specific order, but would have been more efficient if I had:
1. Removed the wiper tray.
2. Reached over and behind the intake plenum to disconnect the two 10-mm machine screws holding a wiring bundle to the plenum.
3. If possible loosen and remove the plenum support bolt from above and behind plenum. This is not absolutely necessary, but can make the plenum removal much easier.
4. Disconnected and remove intake resonator and hose.
5. Disconnected throttle cables, numerous wiring connections and brackets near throttle body.
6. Disconnected vacuum connections to plenum.
7. Unbolt (2 bolts) EGR pipe from throttle body. Approach from below the throttle body.
7. Loosen 4 bolts and remove triangular bracket between alternator and plenum.
8. Disconnected #2, #4, #6 spark plug (front) wires from coil pack; unbolted (4 bolts) coil pack from plenum. Swing coil pack with #1, #3, #5 wires still attached away toward alternator. Note coil pack is numbered.
9. If possible disconnect the PCV from plenum. I forgot to do this and the rubber hose was so brittle; it pretty much disintegrated at the rear valve cover connection when I pulled the plenum. Surprisingly Autozone had the exact hose (with the bend and exact length) on the shelf.
10. Disconnect grounding strap between firewall and plenum. This can be done at the rear of plenum (15mm) or at the firewall (10mm).
11. Remove 2 nuts and 2 bolts holding intake plenum to the intake manifold.
12. Disconnect/remove bolt holding plenum support to head (driver side) below plenum if step 3 was not possible.

At this point, the plenum can be removed. Once that's done, there is plenty of room to work on the valve cover and spark plugs. A lot of steps just to change the plugs, but the engine sure runs much smoother.

Woof
 
#33 ·
Just replaced spark plugs and wires for my 1998 Grand Voyager 3.8 along with rear valve cover gasket. It had125K miles and were on factory plugs. Attacked it from the top. I didn't follow these steps in these specific order, but would have been more efficient if I had:
1. Removed the wiper tray.
2. Reached over and behind the intake plenum to disconnect the two 10-mm machine screws holding a wiring bundle to the plenum.
3. If possible loosen and remove the plenum support bolt from above and behind plenum. This is not absolutely necessary, but can make the plenum removal much easier.
4. Disconnected and remove intake resonator and hose.
5. Disconnected throttle cables, numerous wiring connections and brackets near throttle body.
6. Disconnected vacuum connections to plenum.
7. Unbolt (2 bolts) EGR pipe from throttle body. Approach from below the throttle body.
7. Loosen 4 bolts and remove triangular bracket between alternator and plenum.
8. Disconnected #2, #4, #6 spark plug (front) wires from coil pack; unbolted (4 bolts) coil pack from plenum. Swing coil pack with #1, #3, #5 wires still attached away toward alternator. Note coil pack is numbered.
9. If possible disconnect the PCV from plenum. I forgot to do this and the rubber hose was so brittle; it pretty much disintegrated at the rear valve cover connection when I pulled the plenum. Surprisingly Autozone had the exact hose (with the bend and exact length) on the shelf.
10. Disconnect grounding strap between firewall and plenum. This can be done at the rear of plenum (15mm) or at the firewall (10mm).
11. Remove 2 nuts and 2 bolts holding intake plenum to the intake manifold.
12. Disconnect/remove bolt holding plenum support to head (driver side) below plenum if step 3 was not possible.

At this point, the plenum can be removed. Once that's done, there is plenty of room to work on the valve cover and spark plugs. A lot of steps just to change the plugs, but the engine sure runs much smoother.

Woof
This one helped me so much. Thanks Woofpack! I did my valve cover gaskets and O2 sensor too. It’s really not bad getting that intake plenum off once you do it a time or two. A couple vac lines broke. Hopefully i can get it all back together tomorrow.
 
#30 ·
When I replaced the rear heater hoses a winter ago (borrowing a friend's garage that wasn't quite big enough), I thought it was a perfect time to also swap the rear plugs. I couldn't budge them at all, and didn't want to push my luck, like finding out they were cross-threaded and I had more work to do.
I could have put my impact or long breaker bar on them, but if they need that much force, something ain't right. So not wanting a heater hose replacement to become major engine work in somebody else's space, I left them.

...karl
 
#31 ·
I have a 3.8, 98 with AWD. Done 'em twice from the top now and replaced a lot of the other crap at the same time (valve cover gaskets, rear heater hose, cooling lines). The trick is removing the plenum, alternator, and wiper cowl box. A lot of work. Rumor says plugs every 100k but mine were looking rough at with 80K on the second set.

BTW: This is also a good time to do the tensioner and also BTW, the Gates Solution kit got rid of my "flying belt" problem and no more squeaks and squeals.
 
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