How Often Should I Replace The Spark Plugs? (2004, 2005, 2006, 2007, 2008 3.5L Chevrolet Malibu)

The spark plugs are probably one of the most inexpensive components installed on your 2004, 2005, 2006, 2007, or 2008 Chevy Malibu 3.5L engine. And yet they perform a supercritical job.

Sooner or later they're going to have to be replaced. And there are quite a few factors that influence the replacement interval of the spark plugs. In this article I'll cover a few of them and I'll offer some important tips and suggestions too.

En Español You can find this tutorial in Spanish here: ¿Cuando Debería Reemplazar Las Bujías? (2004-2008 3.5L Malibu) (at:

What Does A Spark Plug Do?

As you're probably already aware your Chevy Malibu 3.5L V6 engine has 6 cylinders. Each cylinder needs air, fuel, and spark to produce power.

Just like the fuel injector is tasked with injecting fuel into the cylinder, it's the spark plug that delivers the spark that the ignition coil creates into the cylinder.

It's the spark that jumps from the spark plug's center electrode to its side electrode that ignites the air-fuel mixture within the cylinder.

Symptoms Of A Bad Spark Plug

When one or more spark plugs, on your 3.5L V6 Chevrolet Malibu, stop working, you're going to see one of several things.

The most common is simply a rough idle or a misfire condition. If the engine is experiencing a misfire condition, you are going to see the check engine light lit up by one or more of the following misfire trouble codes:

  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.

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:

  1. Bad gas mileage.
  2. A heavier exhaust smell coming out of the tailpipe.
  3. Hesitation when you accelerate the vehicle on the road.

What Causes A Spark Plug To Stop Working?

What causes a spark plug to stop working is usually one of two things. The first one is simply normal wear and tear that happens over the course of thousands of miles. The second is the carbon deposits that build up and block the air gap between the center electrode and the side electrode. Once this air gap is blocked, the spark plug can not spark.

What usually causes a spark plug to wear out is the spark that jumps between its air gap. Yep, this spark will eventually wear down even the toughest of metals. Now this doesn't happen overnight but given enough mileage and time the spark plug will wear itself out by simply doing its job.

When a spark plug has its air gap blocked by carbon deposits it's usually because the engine is burning oil. This is especially true of high mileage engines.

Which Spark Plugs Should I Buy?

Your 2004-2007 3.5L V6 Chevy Malibu comes equipped with AC Delco spark plugs.

The AC Delco spark plug brand is the factory original spark plug that all Chevrolet vehicles use. And this is definitely the spark plug that you should be installing when it's time to replace the ones in your Malibu.

Having said that, there are many different brands of spark plugs and for the most part they will all work in your Malibu 3.5L V6 engine.

Of course, some will work better than others. The important thing to keep in mind when replacing the spark plugs on your vehicle with after-market ones, is that they should be platinum type spark plugs and not copper spark plugs.

Should I Use 100,000 Mile Spark Plugs?

If you are buying the original AC Delco spark plugs to install in your 3.5L Chevy Malibu, then these are 100,000 miles spark plugs.

Now the catch here is that if the engine in your Malibu is in perfect working condition (e.g. it's not burning oil) then you're definitely going to see somewhere around 100,000 miles on those spark plugs.

But if you got a high mileage engine that is burning oil, you're not going to see anywhere near 100,000 miles on those spark plugs since carbon buildup will cause them to eventually misfire.

What helps the spark plugs last such a long time is that they have platinum tipped electrodes which don't wear out as much as a regular copper spark plug.

Important Tips And Suggestions

As mentioned before, the spark plugs on your 3.5L V6 Chevrolet Malibu are going to need to be replaced sooner or later. When they do need to be replaced, keep in mind the following tips and suggestions:

TIP 1: Replace the spark plugs with a completely cold engine. This is a very important suggestion because you run the risk of damaging the spark plug threads of the spark plug holes by replacing them with a hot engine.

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. There's a good chance that your brand new spark plugs are billed as being pre gapped. If I were you I would still check the air gap just to make sure that it isn't closed.

The one thing to keep in mind when checking the air gap on pre-gapped spark plugs is to do it very gently with the spark plug gapper. If you use too much force, you could damage the platinum or iridium tips of the center and side electrodes.

If the spark plugs you're using are not billed as being pre-gapped, then you should definitely check their air gap with a spark plug gapper.

Here are the spark plug gap specifications:

  1. 2004-2006 3.5L Chevy Malibu is: 0.060" (1.52mm).
  2. 2007-2008 3.5L Chevy Malibu is: 0.040" (1.02mm)

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.

The torque specification of the spark plugs for the 2004, 2005, 2006, 2007, and 2008 3.5L Chevy Malibu is: 11 ft.lbs.

More 3.5L V6 Chevy Malibu Tutorials

You can find a complete list of 3.5L V6 Chevy Malibu tutorials here: GM 3.5L V6 Index Of Articles.

Here's a list of articles you'll find there:

  1. How To Test The Engine Compression (2004-2008 3.5L Chevrolet Malibu).
  2. How To Do A Cylinder Balance Test (2004-2008 3.5L Malibu).
  3. How To Test A Blown Head Gasket (2004-2008 3.5L Malibu).
  4. How To Do A Cylinder Balance Test (2004-2008 3.5L Malibu).
  5. How To Test The MAP Sensor (2004-2006 3.5L Malibu).
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