The spark plugs are a probably one of the most inexpensive components in the 2.4L (SOHC or DOHC) engine in your Chrysler, Dodge, or Plymouth vehicle.
But it has a very tough job to do since it's exposed to extreme temperatures and pressures inside the engine.
In this article, I'll go over and answer some of the most commonly asked questions about the spark plugs and their replacement interval.
Contents of this tutorial at a glance:
Applies To The Following Vehicles
Quite a few Chrysler, Dodge, and Plymouth vehicles are equipped with the 2.4L 4 cylinder engine. This tutorial applies to the following vehicles:
- 2.4L Chrysler Cirrus: 1995, 1996, 1997, 1998, 1999, 2000
- 2.4L Chrysler PT Cruiser: 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009
- 2.4L Chrysler Sebring: 2001, 2002, 2003, 2004, 2005, 2006
- 2.4L Dodge Caravan: 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007
- 2.4L Dodge Grand Caravan: 1996, 1997
- 2.4L Dodge Stratus: 1995, 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006
- 2.4L Plymouth Breeze: 1997, 1998, 1999, 2000
- 2.4L Plymouth Grand Voyager: 1996, 1997
- 2.4L Plymouth Voyager: 1996, 1997, 1998, 1999, 2000, 2001
What Does A Spark Plug Do?
In a nutshell the spark plug has the task of transmitting the spark that the ignition coil produces to the inside of the cylinder.
This spark then ignites the fuel that the fuel injector has injected into the cylinder.
The resulting explosion of the air-fuel mixture pushes the piston down. With all four cylinders doing the same thing, you get a running engine.
Symptoms Of A Bad Spark Plug
If a cylinder's spark plug stops transmitting spark, then that cylinder will go ‘dead’.
In other words, the cylinder will misfire. This in turn will cause the fuel injection computer to register a misfire trouble code. It will also light up the check engine light on your vehicle's instrument cluster.
You'll see one or more of the following trouble codes:
- P0300: Random Cylinder Misfire.
- P0301: Cylinder #1 Misfire.
- P0302: Cylinder #2 Misfire.
- P0303: Cylinder #3 Misfire.
- P0304: Cylinder #4 Misfire.
Besides a rough idle condition or misfire trouble code, when the spark plugs are worn out you're going to notice that the engine is not as peppy as before.
Other things that you're going to see are:
- Bad gas mileage.
- A heavier exhaust smell coming out of the tailpipe.
- Hesitation when you accelerate the vehicle on the road.
What Causes A Spark Plug To Stop Working?
Spark plugs will usually stop working either because they are worn out or because the air gap (between the center and side electrodes) has been blocked by carbon deposits.
Now spark plugs don't wear out in a short time. But they eventually will. If you're using platinum or iridium tipped spark plugs and the engine is not burning oil, then you're going to see the spark plugs wear out around 100,000 miles.
What causes the center and side electrodes to wear down is the spark that jumps across them. Yep, this park will eventually wear down even the toughest of materials over the course of 100,000 miles.
If the engine is burning oil then the spark plug gap (between the center electrode and side electrode) can get blocked by carbon deposits. Without an air gap between these two electrodes, the spark plug is not able to spark.
How can you tell if the engine is burning oil? Because of the blue smoke coming out of the tailpipe when you accelerate the engine and or having to add oil to the engine on a weekly basis.
Which Spark Plugs Should I Buy?
Your 2.4L equipped Chrysler (Dodge or Plymouth) vehicle comes equipped with Champion copper spark plugs from the factory.
And these are the spark plugs that are the recommended spark plug to buy when it's time to replace them.
Having said that, using platinum or iridium tipped spark plugs (made by Champion or any other manufacturer) will outperform the original Champion copper spark plugs that your Chrysler (Dodge or Plymouth) vehicle came equipped with from the factory.
Platinum or iridium tipped spark plugs can give a service life of around 100,000 miles.
But they will only last up to 100,000 miles if the 2.4L engine in your Chrysler (Dodge or Plymouth) vehicle is not burning oil.
My personal recommendation to you is to buy the Champion platinum tipped spark plugs when it's time to replace them.
Now, if the 2.4L engine in your Chrysler (Dodge or Plymouth) vehicle is burning oil then buy the regular copper spark plugs. Why? Because carbon deposits will accumulate between the electrodes and you're not gonna' see the 100,000 mile service life.
Important Tips And Suggestions
TIP 1: Replace the spark plugs with a completely cold engine. Replacing the spark plugs when the engine is hot can result in damage to the spark plug hole threads.
Stripping the threads of the spark plug holes is a nightmare that you can easily avoid by removing the spark plugs with a cold engine.
TIP 2: Check the air gap of the new spark plugs with a spark plug gapper. You'll need to use a spark plug gapper or feeler gauges to check and set the air gap to the proper specification.
There's a good chance that your brand new spark plugs are billed as being pre-gapped. If I were you, I would still visually check that the air gap (between the electrodes) isn't closed.
Where can you get the spark plug gap specification for you particular vehicle? At your local or online auto parts store where you're buying them.
TIP 3: Use a torque wrench to tighten the spark plugs. If you don't tighten the spark plugs enough you run the risk of having them come out as you're driving down the road. This could also damage the spark plug hole threads in the cylinder heads.
If you over tighten the spark plugs, then you run the risk of damaging the threads of the spark plug hole.
The way to avoid any of these problems is to use a torque wrench to tighten the spark plugs. Now, it's easier said than done because some of the spark plugs are in very tight places and it can be challenging to use a torque wrench on them. Still, you won't go wrong if you use a torque wrench.
You can find the torque specification of the spark plugs for your specific vehicle at your local auto parts store.
More 2.4L Chrysler, Dodge, Plymouth Tutorials
You can find a complete list of 2.4L Dodge tutorials in this index:
Here's a small sample of the tutorials you'll find in the index:
- How To Test Engine Compression (2.4L Chrysler, Dodge, Plymouth).
- How To Test For A Blown Head Gasket (2.4L Chrysler, Dodge, Plymouth).
- Ignition System Wiring Diagram (1995-1998 2.4L Cirrus, Stratus, Breeze).
- Fuel Injector Circuit Wiring Diagram (1995-2000 2.4L Cirrus, Stratus, Breeze).
If this info saved the day, buy me a beer!
