Bruceb66

2003 AE with an A4. Car runs excellent, but I'm no tech....At 15 yrs old and regardless of low mileage, should the factory plugs and wires be replaced? Also, what would be recommended as far as a complete freshen-up at this time? The tranny fluid was replaced last summer, so good to go there and replacing the 2.73's with 3.42's next month, so rear diff fluid will be a non-issue as well.. Thanks.

killian96ss

The plugs and wires are up to you. If it's running good, no need to really change them, but if it were my car I'd upgrade to iridium plugs and MSD or GMPP wires just for peace of mind and better reliability. Belts and hoses should also be replaced due to age since rubber degrades over time just like tires do. I'd also flush and replace the coolant and brake fluid along with inspecting the rubber brake hoses for any cracking and replace if necessary.

Steve

golfnutts

I changed all fluids, hoses, belts, spark plugs and wires, rotors and brakes and cleaned throttle control at 40,000 miles on my 2003 A/E. I think it runs and idles a little better now.

dankhts

15 years is a long time, especially for the wires......plenty of heat cycles etc... change them and the car will run better....maybe even for another 15 years!

93Polo

I was going to say bleed the brakes, flush the coolant, plugs and wires. A topic is currently near the top discussing which plugs and wires. Belts wouldn't be a bad idea but they're easy to check.

Gordy M

With a 15 yr old car I would also change the O2 sensors, especially the fronts. The original Oxygen Sensors were designed when real gas was still available in most of the country. Today that is rarely found and many large states/cities have unique summer gas blends for that area. In the late 2000's with e85 gas becoming more abundant, GM and other manufacturers changed the requirements for Oxygen Sensors to be more resistant to the effects the higher alcohol had on the them.

golfnutts

Never thought of those.....Thanks

Route99

Another vote for changing the fluids (understand your diff fluid will be changed as part of the 3.42 swap). I also agree with changing the plugs and plug wires as well as the belts and hoses. I like the iridium plugs (as well as the GM plugs) and the GMPP wires. If you need to change the brake lines you might want to consider stainless lines. A little more expensive than replacing with stock type lines, but I like the added protection against road debris and the increased rigidity of the brake line.

foggy

Change it ALL !!! 15 years is a long time on any fluids/filters/maint items
Even if it had 10K miles, I'd change all of it... But I'm ocd about my cars and
don't like the thought of anyone working on (or towing) my cars ever

craig-o

Stock plugs were iridium and designed to last >100,000 miles. There’s not much that can degrade performance other than the electrode. Iridium electrodes are amazingly durable, and even at 100k miles, I’ve seen iridium plugs that look practically new. On the other hand, Rock Auto has ididium plugs for $4-6.50 each, so $32-52 for a set, so unless money is extremely tight, why not just replace them?

I’d suggest pulling the plugs and checking to see how they look, including measuring the gap (0.04”). These long-life plugs are great for durability, but they can also tend to fuse to the heads, because they don’t get unscrewed very often. Use a high-temp antiseize when you replace them.

More than likely, when you try to pull the wires off, you’re going to run into some problems getting the wires to release from the plugs, even with spark plug boot pliers. I’d bet that they’ve never been separated, and after 15 years they’re most likely fused together. So you’ll definitely want to have replacements on hand, and some long-handled slip-joint pliers for when you tear the wires from the boots in frustration.

apex26

This is very sound advice. The plugs may be scary tight after fusing to the aluminum all those years. That's what I found in a 2003 Miata in mint condition that has never seen rain, the car ran noticeably better with new. Wires and brake flex lines are a given.

Fast one

I thought the stock plugs were platinum.

killian96ss

That's what I was thinking as well after reading through this. I thought the iridium plugs were phased in at some point during C6 production?

Steve

leadfoot4

My $0.02 worth..........

15 years on the wires, IMHO, is indeed a long time. Heat cycles, etc. the GM Performance "red wires" are a good choice.

15 years of the plugs being in place are another situation. While they may be functioning properly, I'd be concerned about them becoming "welded" in place. I suggest, at minimum, the plugs come out and get a dab of never-seize, then put back in.

And, as others have suggested, flesh fluids throughout.

Ed Ramberger

Here's a question to everyone who says to change wires due to heat cycles - the car only has 40k. How are you determining it has excessive heat cycles that require a change. I would argue that's an invalid statement.

The plugs are spec'd for much longer than that and the only concern might be sticking in the heads. But my personal experience was that at 91k on my 2004, the plugs came out easily. The wires were changed at that time. The OE irridium updated plugs went in with a few drops of oil on the threads as recommended by the FSM. Factory plugs were not coated with anti-seize and came out perfect after 14 years and 91k, so I think following the FSM will yield the same results down the road.

If he pulls the plugs to check, he will 100% guaranteed destroy some wires in the process.

So, to the OP - if you decide to go down the route of checking, plan on replacing plugs and wires because you will destroy the wires and why would you reinstall used plugs for all that hassle?

C6_Racer_X

You answered your own question with this:
If the boot at the plug is so hardened/brittle/deteriorated that you can't pull the wire boot off and reuse it, the wire is already well beyond its "best by" date. You didn't destroy the wires by pulling them off. Time destroyed them, and you just discovered that they were aged/heat cycled/worn beyond their service life.

Ed Ramberger

Has nothing to do with brittle - the boots get stuck on the plugs normally with time - doesn't mean they're bad. This can happen after 10k miles too. I wonder how many of these you've changed wires on - half of them just the way you have to grab them due to the way they are buried will pull a wire from the boot once they've been on a while.

C6_Racer_X

I always use a good set of spark plug boot pliers. I've got several different choices in the tool box. The ones I go to most often are the ones with the 5 way adjustable jaws.

I can't remember doing a C5. I did the wires on the C6 last summer, not long after she got the thing. We went with new plugs as well. I do remember that I had to go to the ring nose pliers on a couple of the wires.

I never grab except (with appropriate pliers) by the base of the boot, down against the metal part of the plug, and I always twist from that end before I try to pull.

If you're trying to pull the plug wire boots with your fingers, you're doing it all wrong. There are tools specific for this task.

I've worked on a number of LS1's in trucks, Camaros and Pontiacs, but I don't specifically remember working on a C5 for plugs/wires.

Oh, and I always use plenty of dielectric grease in the spark plug boots, to avoid them getting stuck in the future.

Ed Ramberger

Here is a C5 OE wire from my car. You will see that your only choice is to pull on the metal cover.

apex26

OP: dis-similiar metals in constant contact with each other are notorious for causing corrosion, hence the plugs fusing issue.