How Often Should I Replace The Spark Plugs? (4.7L Dodge Dakota)

Replacing the spark plugs on your 4.7L Dodge Dakota or Durango is something that you'll have to do sooner or later and you might be wondering what the spark plugs should you use, how often they should be replaced, and should you gap them.

This article will answer some of the most common questions asked about spark plugs.

What Does A Spark Plug Do?

Each of the eight cylinders in your 4.7L v8 engine needs air, fuel, and spark to create power.

It's the spark plug that has the critical job of delivering the spark that the ignition coil creates into the cylinder it's bolted into.

The spark then ignites the air-fuel mixture within the cylinder to push the piston down.

When you consider the extreme temperatures and pressures within the cylinder, the humble spark plug indeed performs a pretty amazing job.

Symptoms Of Worn Spark Plugs

Depending on the severity of the wear and tear on the spark plugs, you're going to notice one or more symptoms.

The most common one is bad gas mileage. You could also notice a heavier exhaust smell coming out of the exhaust pipe.

If the spark plugs are severely worn out, you're going to notice a misfire under load and/or a rough idle condition when you come to stop. The misfire will cause the PCM, on your 4.7L Dodge Dakota or Durango, to light up the check engine light with one or several misfire trouble codes.

You'll see one or more of the following:

  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.
  8. P0307: Cylinder #7 Misfire.
  9. P0308: Cylinder #8 Misfire.

What Causes The Spark Plugs To Stop Working?

The spark that the spark plug delivers to the inside of the cylinder eventually will wear down the center and side electrodes. The end result of this will be that the air gap between them will increase to the point that spark cannot jump across it. At this juncture, the cylinder will misfire.

But worn out spark plugs are not the only cause of spark plug failure. The other are carbon deposits accumulating on the center electrode. These carbon deposits will eventually close the air gap between the electrodes. The end result is a spark plug that can no longer spark.

These carbon deposits (accumulating on the spark plug's electrodes) are usually the end result of a high mileage engine that is burning oil.

Which Spark Plugs Should I Buy?

The best spark plug to use on your 4.7L Dodge Durango or Dakota is the factory original spark plug. And this bad boy is the Champion spark plug brand.

The truth of the matter is that it doesn't matter what brand of spark plug you use because they're all going to work. Of course some will work better than others.

Some of the spark plugs that will fit your 4.7L Dodge Dakota or Durango can get very pricey. This is usually because they're made in part with exotic materials like platinum or iridium.

The one thing you should keep in mind when considering buying the expensive spark plugs is if your 4.7L v8 engine is burning oil. And I'll explain why.

If the engine is burning oil, then whether you have an expensive spark plug made with exotic metals or the cheapy ones they are all going to accumulate carbon buildup between the electrodes at the exact same rate and you're going to have to replace them at shorter intervals (since these carbon deposits will eventually affect their performance). So in the long run, using an inexpensive spark plug makes more financial sense.

Should I Buy The 100,000 Mile Spark Plugs?

The spark plugs that are billed as lasting 100,000 miles are the ones made with platinum or tipped with iridium.

And I can tell you that they really do last a very long time. But this is only true if the engine is not burning oil.

So if the engine in your 4.7L Dodge Durango or Dakota isn't burning oil, then these spark plugs are good fit.

Important Tips And Suggestions

TIP 1: Replace the spark plugs with a cold engine . Removing the spark plugs with a hot engine increases the risk of stripping the threads in the spark plug holes.

This risk is compounded by the fact that both cylinder heads, on your 4.7L v8 engine, are made of aluminum.

What you can do, to cool down the engine fast, is to place a box fan (or any type of house fan) on top of the engine. This will cool the engine down in around 15 to 30 minutes.

TIP 2: Check the air gap of the new spark plugs before installing them. There's a good chance that the packaging of your new spark plugs indicates that they are already pre-gapped but it doesn't hurt to check and make sure.

It's been my experience that some of these pre-gapped spark plugs have had their air-gap closed right out of the box (they posibly had been dropped). Not only that, I have solved quite a few misfire problems that were caused by pre-gapped spark plugs that had a problem with their air gap.

If you are installing pre-gapped spark plugs, check their air gap very gently with a spark plug gapper or you run the risk of damaging the platinum or iridium tips on the center and side electrodes.

TIP 3: Use a torque wrench to tighten the spark plugs. You run the risk of stripping the threads in the spark plug holes if you over tighten them.

If they're not tightened enough, then they could work themselves out while you're driving down the road. This could also damage the threads in the spark plug holes.

So the best way to keep from having any complications is to use a torque wrench to tighten the spark plugs to their torque specification.

More 4.7L Dodge Tutorials

You can find a complete list of 4.7L Dodge tutorials in this index:

  1. Dodge 4.7L Index of Articles.

Here's a small sample of the tutorials you'll find in the index:

  1. How To Test The MAP Sensor (2000-2001 4.7L Dakota, Durango).
  2. How To Test The Throttle Position Sensor (2000-2007 4.7L Dodge).
  3. How To Test The Blower Motor Resistor (2001-2004 Dakota, Durango).
  4. Specifications 2000-2003 4.7L Dodge Dakota And Durango.
  5. How To Diagnose A Misfire (2000-2003 4.7L Dodge Dakota).
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