How to change spark plugs - 2003 Chevy Impala

Greetings all -

I am hoping that I can change my own spark plugs. I have done it before though not in this model. I understand that the back three plugs can be very difficult to get to. What is the trick to do it?

Thanks in advance -


On V6, or V8, engines, which sit crosswise in the engine bay, it is often difficult to access the spark plugs next to the firewall (bulkhead).
Some repair manuals instruct to remove the intake plenum, etc. Removing the plenum has the potential, upon re-installation, of creating a vacuum leak from poor sealing, trapped wires, etc.

I have found it best to go in from the end of the engine (the side of the engine bay). Often, the alternator and it’s bracket, or a power steering pump (it could be a another component) have to be removed to reach between the engine and the firewall to the spark plugs. I found this method to be quicker, and easier.

On some vehicles (Chevy Venture, for one) the engine has to be pulled forward, In addition to removing parts, for adequate clearance to the spark plugs. The engine is supported with a jack (or block), the front motor mount is removed, and a ratcheting tie-down strap (available from Walmart) is used to pull the engine forward a few inches.

This job is - without question - a PITA for DIY. Depending on what kinds of things need to be done (e.g. actually moving the engine or removing alternator bracket) it is really difficult w/out the car on a lift.

The front plugs should be incredibly easy - the back three are the problem. Unless you have access to a lift, I would think twice. I did the plugs in my Caravan (w/out having to remove any parts), but was sore for about a week from the gymnastics I had to do - going up behind the engine from under the car. It is also the case that I really have little idea of how much crud fell into the cylinder - I blew things out as best I could but wasn’t even able to see what I was doing - all by feel.

At the very least, if you do decide to do it (like in your driveway with ramps or stands) leave a lot of time and take your time; a look at a shop manual wouldn’t hurt; pick up some extra advil for the muscle aches and other things; install 100K mile rated plugs so that you likely never have to do it again.

Thanks to both hellokit and admitted amateur for theie reponses. I had gotten a quote for about $150 for this from a repair shop. Although I trust their work the price seemed a bit high. Now I understand better why they tagged on the extra bucks.

I’ll ponder this but likely end up taking it in. I’m not that experienced and could easily end up creating additional problems for myself.


Given that I am on a low budget, I considered buying the plugs and wires, doing the front three and then - if I tried the back three and decided I couldn’t do it or it wasn’t worth the trouble - driving it into the garage for the back three. I have no idea how much $$ that would save. In the end I just got stubborn about it and got it done.

I have an 01 Impala, and when the plugs come time to be changed, I’d likely follow admitted amateur’s course of action - replace the front three, reproductive activity the back three. And $150 isn’t that bad to change the plugs on a transverse V6. My dad’s gotten a quote on his V6 Sonata to replace the plugs - $600!! In order to get at the back three, one must remove the intake plenum, fuel rails, throttle body, coolant hoses, and a few other things. Oh, and the engine must be tilted forward. So, yeah, there’s no way in hell I’d even attempt to do that. I don’t have time.

You may not need plugs until the car hits 90,000 miles. If your car already has more miles, it was intended that you trade it in. It wasn’t designed any better than that although it may last longer. Another way is to wait until the intake manifold starts leaking and have the plugs changed then.

I have a 03 Chevy Impala LS with the 3.8L V6 and I already know that it’s going to be a P. I.T.A. thankfully my uncle is helping me with the tune-up

This is a 10 year old thread.

I’ve done transversely mounted engine spark plugs on GM sedans in the past, and they can be difficult. The front plugs are straightforward, but the rear plugs can be difficult. One car required a universal joint on the ratchet wrench, and applying torque was much more difficult. I ended up standing on top of the engine under the hood with a 4’ pole over the wrench handle before I finally got the right rear plug loose. I should have had my wife video the show. On mute, of course.

In the late 70’s I owned a Monza Spyder with a V8 engine. When I tried to replace the spark plugs one Saturday afternoon…I ran into a big problem with clearance. The manual said to remove the wheel…disconnect the motor mount and raise the engine. Repeat for the opposite side. I changed the spark plugs and put the car up for sale. I built a V8 Vega a couple of weeks later. No problem with changing spark plugs in that vehicle.