Tuesday, December 31, 2013

Changing Spark Plugs and Wires on a 2002 Dodge Grand Caravan 3.8 Liter V6

Tonight I changed the spark plug and wires on our 2002 Dodge Grand Caravan minivan.  It has over 150,000 miles and it was definitely time.

Tools:
The only tool really required for this was a Ratchet, 4" extension, and a 5/8 spark plug socket.

There are a couple of optional tools.  I used my air compressor to blow the dust and car droppings out of the spark plug holes, but that's not really necessary.  If you don't have an air compressor, canned air will do the job. 

I also used a $1.99 spark plug gap gauge to verify the gap on the new spark plugs.  More on that further down in the post.

Parts:
I got a set of wires and 6 double platinum plugs from AutoZone.  I could have saved about $20 getting them from RockAuto, but I was bored and wanted to do this tonight.


Consumables:
I also bought the little packs of anti-seize and spark plug boot lubricant.

Procedure:
Changing Plugs and wires on this van is fairly straightforward.

First, the OCD bits to make sure you got the right parts and make the job easy.
Lay out all of your new spark plug wires from smallest to largest.
Next, lay out all of the new spark plugs.  Using a gap gauge, verify the gap on all of them is the same.  5 of mine were perfect.  One of them had was 0.020" over, and had to be adjusted.  That is large enough that it would have made a performance difference.

While your hands are still clean, apply a quarter-pea sized amount of anti-seize to the threads of each plug, and a similar amount of boot lubricant to the porcelain end of each new plug.  Smear them in.

Disconnect the negative battery cable and cover the battery so you don't set a tool down and short the terminals.

Blow out the area around the still-installed spark plugs so that muckety-muck doesn't go into your cylinders.

One last check before digging in with both hands.  I take off one easy-to-reach plug and verify that the new plugs are the same length from the base of the threaded part to the end of the terminal and that the threads are the same size.  This has bitten me before, so I'm obsessive about it.

Changing the rest of the plugs and wires are pretty easy.  The front three are right out in the open.  The back three you have to reach around to get too, but there is plenty of room to work.  One Tip: I disconnected two vacuum hoses from the upper right hand side of the intake manifold so I'd have easier access to the back plugs.  (Blue arrow)  Be extra careful with the hard plastic vacuum lines.  I managed to snap one in spite of myself.  You can see it duct-taped together in the picture below (yellow arrow).  I'll replace that tomorrow when I drive by the auto parts store.  These hard lines are crazy brittle when it's cold and tonight it was 30F in the garage.






I'm of the change-one-plug-at-a-time camp, so I remove and replace each plug and wire separately.  This way I can't possibly screw up the firing order of the cylinders.  If you lose track of the wires, or get them mixed up, here is how mine are connected.

The Engine Cylinders are like this...

135
246

The ignition coil connectors are like this...

531
246


Here are my old plugs.  The electrodes are severely worn.  It was definitely time for replacement.  Notice how the three on the right have a coating of shiny oil?  It looks like that rear valve cover gasket is leaking a little.  I'll add that to the list. 

Final thoughts:
Dodge has radically improved the access on this model vs. the 1995 one I worked on previously.  On that nightmare you had to undo an engine mount and tilt the engine to reach the #1 cylinder.  On this new one I could reach all of the plugs easily with both hands.  Thanks Dodge!

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