Sorry to start a new thread, but wanted this to show when the next poor soul searches for help in desperation, bleeding, and wishing for a sailor to help with descriptive language for our much loved Crossfire.

Before you start, or before you break anything else, go buy a pair of spark plug wire boot pliers. I never had heard of such, but found the oldest guy I could see at the local AutoZone, told him what I thought I needed, and he had one pair. Well worth the $13!

Buy THREE 1.5 inch extensions for your 3/8 drive ratchet. One, in combination with the 3 inch extension you thought was enough, will make things much easier on the driver's side. Throw the wobble joint in the trash can. Check to be sure you have the correct TORX wrench for removing the coil packs.

With a 3 inch and 1.5 inch extension, all the plugs are easy enough, with room for the torque wrench, EXCEPT the rear plug on the passenger side.

For that plug, I had to start by placing the spark plug socket and one extension on the plug, then add the other two extensions, ONE AT A TIME. That done, there was room for the ratchet and for the torque wrench.

Plug wire removal and installation is harder than dealing with the plugs. Use the pliers for removal, and use dielectric grease prior to installation (THANKS Waldig for that information!). I could not get a single wire securely seated without the grease. With it, most were hard, others were much worse.

The coil packs are marked "a" and "b", and the heads are marked "a" and "b" at each cylinder, so don't worry about mixing up plug wires. Check the price of a new set first if you are tempted to vent your frustration.

Avoid beer, coffee, and sinus medications. If you are taking prescription antidepressants, be sure you're adequately medicated.

Like any job, with correct tools before you start, this won't seem nearly as bad. Without them, you probably already know what I'm describing here.

Good luck.

Michael
05 Roadster, Limited, black 6 spd

 

Yep, removed the plugs twice so far and was a real pain. No matter what tools we buy, it is still one pain in the a$$.

 

Buy a Koch Tools Mercedes Benz V6 spark plug boot puller 17mm. The wrench was originally used to adjust valves on early MB's. With the coil packs removed, use the open end of the wrench to slip under the **** end of the boot and pop them loose. The Koch tool is around $20 or an original MB tool can be purchased for about double the Koch price. Bought it on E Bay.

 

Thanks for making my morning!

 

Here's a YouTube Video on the tool and boot replacement.

Mercedes-Benz M112 / M113 Spark Plug Boot Wrench - YouTube

 

Thanks very much for that one..... getting those dang boots off and on is the biggest pain in changing the plugs....

 

I changed my spark plugs over the weekend and it took about 2 hours. I'd like to add a couple of tips.

1. Regarding the 17 mm Mercedes wrench for removing the boots, I just used a standard open end 17 mm wrench to wiggle them off. I gently wiggled the wrench with one hand and had my other hand below the boot to support it and pull on it. Each came off with about 10 wiggles. For the back spark plugs, I angled the wrench to the rear.

2. Stack the socket and extensions: I slipped the 5/8" deep socket over the spark plug, inserted the 3" extension, then snapped the ratchet onto the extension. That worked ever time. To remove the spark plug, reverse that order. Snap the socket off, spin the spark plug the rest of the way, then remove the 3" extension then the 5/8" deep socket. If the socket gets oily, use a flat screw driver to pop the extension off.

I thought it would be much worse after reading these posts but other than taking 2 hours, it wasn't bad.

 

Thanks for resurrecting an old but valuable thread on the spark plug replacement. Very glad to hear it worked well for you!

 

Adding a small touch of dielectric grease to the body of the plug keeps them from getting MARRIED to the boot - one another and allows better removal. Good stuff to use. WDY

 

Here's another hint :
Remove both valve covers, just unplug all the plug wires and coil actuator wires, leave the coil packs in place.
You will now have easy access to the plug wires AND the plugs.

 

Heres another suggestion change them plug wires to these. Magnecor KV85 8.5mm Competition Ignition Cables

Then you dont have to worry about them fusing with the block. That will speed up at least half the process. I had to cut some of the oem plug wires because they were frozen. I dont have to worry about that anymore with the new plug wires.

 

A newbie here...just got my 2004 coupe. I wanted to change the plugs and went to Needwings to check on the price. They are selling them in sets of 12... don't we need only 6 plugs?

I'm really confused now and after reading what it takes to change them in this post... the $262 parts and labor the dealer quoted me doesn't sound too bad after all... Lol!

 

There really are 12 plugs, 2 per cylinder like an airplane.