How Often Should I Change The Spark Plugs (1994-2010 3.8L V6 Grand Caravan, Town & Country, Grand Voyager)

Spark plugs are designed to last a very long time. Depending on the type of spark plugs you have on your minivan, copper spark plugs or platinum tip spark plugs, the spark plug will last around 50,000 miles to 100,000 miles.

They'll last this long only if they fail due to normal wear and tear, unfortunately quite a few things will cause them to fail much sooner.

In this article I'll go into some of the things that can cause them to fail before their time.

En Español You can find this tutorial in Spanish here: Causas Comunes De Falla De La Bujía (3.8L V6 Chrysler, Dodge, Plymouth Mini-Van) (at: autotecnico-online.com).

APPLIES TO: This tutorial applies to the following vehicles:

  1. 3.8L V6 Chrysler Town & Country: 1994, 1995, 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010.
  2. 3.8L V6 Dodge Grand Caravan: 1994, 1995, 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010.
  3. 3.8L V6 Plymouth Voyager: 1994, 1995, 1996.
  4. 3.8L V6 Plymouth Grand Voyager: 1994, 1995, 1996, 1997, 1999.

What Causes Spark Plugs To Wear Out?

A spark plug will wear out due to the spark that jumps between its center and side electrode.

This spark will wear out even the toughest materials that can be mined from the center of the Earth.

Of course this wear and tear of the electrodes doesn't happen overnight, but drive enough miles and they will wear down to a nub.

Copper spark plugs, which are the factory equipment spark plugs for the 3.8L V6 Chrysler, Dodge, and Plymouth minivans, will wear out around 50,000-60,000 miles.

Platinum tip spark plugs will normally wear out around 100,000 miles.

The other thing that causes a spark plug to fail, is carbon deposits that accumulate and block the electrodes.

These carbon deposits are the result of the engine burning oil within the cylinder or cylinders.

Once the spark plug's electrodes get blocked with carbon, spark won't be able to jump between them and you're going to have a bona fide misfire causing an engine performance problem.

If your mini-van is equipped with OBD II (1996+), you're going to see the check engine light illuminated with a specific misfire trouble code:

  1. P0300 Random Cylinder Misfire.
  2. P0301 Cylinder #1 Misfire.
  3. P0302 Cylinder #2 Misfire.
  4. P0303 Cylinder #3 Misfire.
  5. P0304 Cylinder #4 Misfire.
  6. P0305 Cylinder #5 Misfire.
  7. P0306 Cylinder #6 Misfire.

When Should I Replace The Spark Plugs?

There are several factors to consider when deciding to replace the spark plugs.

These are:

  1. Is the engine burning oil?
  2. Is the engine suffering a rough idle condition?
  3. Does the engine have copper spark plugs and 50,000 mile have passed since when they were replaced.
  4. Is the check engine light illuminated by a misfire trouble code (on OBD II equipped minivans)?

If the engine is burning oil: You'll need to check and replace them as soon as the engine starts idling rough (like when you come to a stop at a traffic light) or the check engine light illuminates with a misfire trouble code.

Depending on how fast the spark plugs get blocked with carbon deposits, you could be replacing the spark plugs every few months.

How can you find out if the engine is burning oil? You'll know because:

  1. You have to add oil on a weekly basis to the engine.
  2. You see blue smoke coming out of the tail pipe when you accelerate the engine under load.
  3. You see blue smoke coming out of the tail pipe when you first start up the engine.

If the engine IS NOT burning oil: You'll be able to enjoy the full service life of the spark plugs before its time to change them in your min-van.

If you're using the original equipment copper spark plugs, on your 3.8L V6 Grand Caravan (Town & Country, Grand Caravan), you'll be replacing them around 50,000 miles.

If you're using platinum or iridium tipped spark plugs, you'll usually see a service life of around 100,000 miles.

Which Spark Plugs Should I Buy: Champion or Brand X?

The spark plug that your 3.8L V6 Grand Caravan (Town & Country, Grand Caravan) comes with from the factory is the Champion brand copper spark plug.

Generally, this is the spark plug that you should buy and install on your mini-van when deciding to replace them.

Now having said that, any spark plug from any other brand that is specifically designed to work on your particular 3.8L V6 Grand Caravan (Town & Country, Grand Caravan) will work.

I personally recommend installing platinum tipped spark plugs instead of the copper spark plugs (if your mini-van's engine isn't burning oil).

Of course, some spark plugs are cheaper than others. Here are my recommendations:

If your engine is burning oil: I would suggest buying the cheapest copper spark plugs (even if it's Brand X spark plugs).

Using the most expensive spark plugs will not make a lick of difference, since the engine is burning oil and they're gonna' get fouled up with oil/carbon pretty soon and cause a misfire.

If your engine IS NOT burning oil: Then buy I would suggest buying platinum tipped spark plugs. Brand X platinum tipped spark plugs will work fine.

Using platinum tipped spark plugs are your best bet to have the best engine performance possible.

Other Causes Of Spark Plug Failure

Spark plugs that are not firing spark will cause a misfire condition and if your mini-van is OBD II equipped, you'll see a misfire code (P0300, P0301, P0302, P0303, P0304, P0305, P0306) illuminating the check engine light.

There are two specific conditions that can cause this problem:

Internal mechanical problems are causing the spark plugs to get fouled up with gasoline or carbon.

The most likely causes are:

  1. The misfiring cylinder is burning oil because its piston oil control rings are severely worn or its cylinder head valves have bad valve stem seals.
  2. Fuel injection problems causing the spark plugs to get fuel fouled.
  3. Bad spark plug wire not transmitting spark from the ignition coil pack to the spark plug.
  4. Bad ignition coil pack.
  5. Low compression problems in a specific cylinder and causing its spark plug to become fuel fouled or carbon clogged.

Human error causing the spark plug to malfunction.

This is usually caused by spark plug installation problems such as:

  1. Breaking the spark plug's insulator (the porcelain part) when tightening the spark plug.
  2. Dropping the spark plug and breaking its insulator.
  3. Dropping the spark plug and closing the air gap between the center electrode and the side (ground) electrode.
  4. The spark plug's air gap is not within the specified range.
  5. Power washing the engine while it's hot (which causes the spark plug's porcelain insulator to crack).

More 3.8L V6 Grand Caravan, Town & Country, And Grand Voyager Tutorials

You can find a complete list of tutorials in this index: Chrysler 3.8L Index Of Articles.

  1. How To Test A Blown Head Gasket (3.8L V6 Chrysler, Dodge, Plymouth Min-Van).
  2. How To Test The MAP Sensor (1996-2000 3.8L V6 Chrysler, Dodge, Plymouth Mini-Van).
  3. How To Test Engine Compression (3.8L V6 Chrysler, Dodge, Plymouth Min-Van).
  4. Ignition System Circuit Diagram (1996-1997 3.8L Chrysler, Dodge, Plymouth Mini-Van).
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Chrysler Vehicles:

  • Town & Country 3.8L
    • 1994, 1995, 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010

Dodge Vehicles:

  • Grand Caravan 3.8L
    • 1994, 1995, 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010

Plymouth Vehicles:

  • Voyager 3.8L
    • 1994, 1995, 1996
  • Grand Voyager 3.8L
    • 1994, 1995, 1996, 1997, 1999