Reviewed my manual and it recommends changing spark plugs at 100k or 5 years. Well I'm at 10 years and 56k on the roadster and 27k on the SRT6. Should I change the spark plugs? Performance and gas mileage have been consistent (good) since I purchased the cars in 2005 and 2008.

 

I'm at 30,000 and 10 years and I have no intention of replacing them. These aren't the plugs from the '60s.

 

Dave, the biggest problem that you might have is when or if you do decide to replace them they won't come out at all, stuck. Other than that they will probable function just fine for years to come and I agree with your statement. I changed mine a couple of years ago at 50000 miles and a couple of them acted as if they were frozen in there for a while and were quite difficult to turn making loud popping noises.

 

That is a very good point, I expect that they are treated in an effort to stop them binding to the heads. I will remove them at some time to prevent this.

 

Dave, great expectation! I would suggest they do not put anything on the plugs, as they slap them together day and night on an assembly line. If involves an added cost in time/manpower/materials, they will most likely nix it. Another consideration, they make monies repairing the heads when the plugs 'rip out' and break/strip during repairs (back end costs customers incur). And, come on, we do all own a benz/Chrysler red-headed stepchild... I especially like your idea of getting In there and taking them out and putting something on the threads as a preventive measure.


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I expect the plug threads are treated when manufactured.

 

If it is an SRT6 engine from AMG, they are assembled by a single technician and may well have something on them. I went to colder plugs after all the engine mods at about 40K and had no difficulty with removal.

 

I had a plug stick in my wifes car a while back, I sprayed the plug very good with Kroil penetrating oil, then let the car idle for about 15 minutes to get it good and warm with the oil around it. The following day after the engine was cooled back down the plug came out pretty easy. Anti seize the new ones for sure as you put them back in.

And then there's this.....

There's also a product called Loctite Freeze & Release that's very effective at loosening stuck plugs...

http://www.henkelna.com/industrial/p...=8797940809729


As for the anti-seize.... From the Permatex website:

 

Decided to replace the original spark plugs in my 2004 coupe with only 32,000 miles due to the car being 11 years old. I know the plugs can go much longer, but I wanted to get them out to prevent the possibility of seizure. I also wanted, as a matter of pride, to attempt the dreaded spark plug replacement as a personal challenge, and no way was I going to pay a dealer to do it. I also had a leaking valve cover which I first removed to make the plug change easier (I replaced rubber gaskets on both valve covers). I was a little anxious at first after reading all the horror stories on this site, but the job wasn't nearly as bad as I anticipated. This may have been due to my plodding geriatric pace and frequent beer breaks. The boot removal tool helps a lot, as does the dielectric grease on the new plugs. Did I mention frequent beer breaks? It also helps to have a torque wrench, universal 3/8" drive coupling, and the proper Torx bits. My advice is to work slowly, be patient, torque the plugs to spec if you have the wrench (otherwise a 90 to 100 degree turn after contact), use anti-seize on the threads (there's some controversy about this) and check the position and tightness of all the wires and boots when you're finished. I double-checked mine and found one boot that wasn't completely seated on the plug. Now the oil leak is fixed and the idle has smoothed out. It was a job well worth the effort. I also decided to install a new serpentine belt. That was a breeze.

 

+1 to all that.
I've been preaching for years on removing the valve covers to do a complete plug change.
Well worth the time required, and the skin you keep on your hands and forearms.
Plus, you can really tell when the plug boots are properly seated.
I also got to see the innards at 60,000 miles and was quite pleased at the lack of brown carbon buildup :

 

Dare I say it? Cool.

For a quick freeze on a part, use the compressed gas dusters used on keyboards etc, put the nozzle close to the object and give it a blast. Freezes up real quick, do not do it on skin.
I removed chewing gum from my Crossfire car mat with it, the gum came off in frozen lumps leaving no trace

 

It's heartening to see how proper oil maintenance pays off. I only put around 1,500 miles a year on mine, so I change the Mobil 0W-40 every two years. Maintenance on my Crossfire is on a time basis, not mileage. Put a new electro-hydraulic plate in the trans a few years ago with around 24,000 miles. The trans oil was black, apparently due to age (and possibly water contamination), not mileage. I've always practiced aviation-type maintenance on my cars, that is, maintenance based on both time and usage.

 

Me too - the annual is due again Aug 2016.

 

Yes! This was how I noticed that one boot was loose...it stuck out a bit compared to the others.

 

My 2005 has 120000 kms on it and saw no indication the plugs had been changed, so I changed them with plugs from needswings. As above, some of them were harder to get out. I was surprised at the smoother idle that was immediately noticeable. Attributable to plugs, dielectric grease in connections, firmly connected boots, the TLC throughout the job? Who knows, but am glad I did it.

 

At just close to 100,000 miles, my Graphite started missing and throwing O2 codes. 12 plugs and 12 plug wires ended all that. I'd not realized how crappy the car was running until after the work was done - conclusion: 100,000 miles (160km) is way too long to leave them in there.

Additionally, a fifteen year old car with that mileage on it should get plug wires as well as plugs.

 

Will be getting the plug wires next!

BTW, might anyone know where one can find replacement wire sockets that plug into the coil packs? Most of mine had the clips broken on them and I would prefer to replace them. I understand we might be able to find little gizmos that can help us get the wires out of the sockets without damaging them.

Many thanks,

John

 

OK. My 2004 Crossfire Coupe passed 100K miles in January, and I started taking care of all the maintenance requirements. I change the oil and filter every 5000 miles, and change the trans filter, and flush the trans per the advice of "Car D. Ologist" on Youtube (He deals with his Mercedes Benz, but it's the same engine/trans, and his presentation is excellent and works very well.) every 25K miles.

NOW, it was time for the spark plugs. Have never changed them, and worried A LOT about doing damage when I extracted them. I could see being stuck with torn out threads due to it now being 21 years and 100K miles since they were installed. I REALLY dreaded doing this, but decided, for better or worse, to go ahead and get it out of the way.

FIRST OFF, if your valve covers or breather cover are not leaking, DO NOT REMOVE THEM for a spark plug change!. HUGE extra waste of time, and you risk damaging the coil pack connectors, etc. I removed the R/H side valve cover because it was leaking, and it looked like it would be easier. THIS IS AN ILLUSION AND MAKES NO DIFFERENCE TO THE EFFORT REQUIRED FOR THE SPARK PLUG CHANGE!.

My NEXT consideration was how do I insure the plugs will come out? I finally devised a plan where I would warm the engine up with a drive, then apply a freezing solution to the plugs, and then put the spark plug socket on the plug, and see if they would break loose.

The special plug wire wrench IS critical!. It will help you remove the spark plug wires, without any damage whatsoever. I popped off all the spark plug wires on one side, in about 30 seconds total. Easy removal and no damage. The special spark plug socket with it's flex drive is ALSO critical. I rated THOSE TWO ITEMS AS BEING ABSOLUTELY NECESSARY FOR A SUCCESSFUL SPARK PLUG CHANGE!

The next thing was to remove the coil packs. I decided NOT TO DISCONNECT ANYTHING ON THEM, BUT TO JUST REMOVE THE ONE RETAINING BOLT ON EACH COIL,THEN GENTLY LIFT THE COILS AND SPARK PLUG WIRES, AND ROLL THEM OVER VERY GENTLY SO THEY WERE OUT OF THE WAY. I disconnected NOTHING, and NOTHING broke on any of the coil packs. Someone on here with long experience stated that the original spark plug wire assemblies were far better than any spares replacement currently available, and that you should not change them unless you actually had one that was physically damaged. Thus I decided not to replace any spark plug wires.

The next thing was the dreaded spark plug removal. During preparation for this, the first thing I did was get a can of "Freeze-It" at a local electrical store. My can was 185 grams, or about 9 ounces, and this was more than sufficient to flood each plug with the spray, and I still had some left over. Before I apply it, I first checked my replacement spark plugs (NGK) with a socket. What I wanted was a socket that had clearance and a loose fit all the way down to the spark plug wrenching boss area. This socket is NOT to engage the plug but to sit loosely over it, to form a loose cavity around the wrenching area for the Freezing solution to run into, flood around the metal boss on the spark plug, and freeze the plug body itself, thus shrinking it and hopefully reducing any binding to a minimum, If you use a socket that actually fits the plug, YOU WILL BLOCK OFF THE FLOW OF FREEZE-IT TO JUST THE CERAMIC AREA AT THE TOP OF THE PLUG, AND THIS WILL NOT HELP WITH REMOVAL AT ALL. The Freeze-It comes with a flexible straw. I placed the loose socket over the plug, put the flexible straw down through the square drive hole in the end of the deep socket, and flooded the plug with the Freeze-It. I then lifted the loose socket off the plug, put the special flexible spark plug socket on it, and easily broke them all loose, one after another, all the way down the row of 6 plugs. It worked perfectly, they all broke loose easily, and I then went back to the first plug, and screwed it all the way out, checked the gap on the new plug, put nickel anti-seize on the threads of the new plug, dropped it into place, and started it with the socket, driven by my fingers only. I tightened them down to just snug, and moved on to the next plug, until I had all 6 plugs on that side changed. I then went down the row of plugs and torqued them all, and that completed the spark plug change on that side.

The next aggravation was reinstalling the valve cover. I had Fel-Pro valve cover gaskets, which I expected would be VERY GOOD, but in fact were pretty poor. I got the cover on, and found it was leaking badly all over. There was no excuse for this, as I had degreased the breather cover and valve cover, washed them in solvent, and then rinsed them in MEK. They were absolutely, spotlessly clean. The breather was sealed with Permatex sealer, and that part worked fine. A couple days later, I pulled the cover off again. I found the rubber gasket had been molded about 10-12 mm TOO LONG. From long experience with these gaskets on jet engines and aircraft, I KNOW that such a gasket MUST BE PRECISELY THE CORRECT LENGTH. IF THEY ARE TOO LONG, THEY WILL NOT WORK!. IF THEY ARE TOO SHORT, THEY WILL NOT WORK!. Ideally, they should be within 010" of correct length for the sealing surface. Fel-Pro's approximation of what they felt was a good gasket was woefully off.

After cleaning the cover up again, and again making it spotless, I laid the gasket into the grooves, slowly and gently, and determined where the excess could be accumulated and removed. This was on the LOWER side of the valve cover, at about the mid point of the length of the cover. Finessing the gasket into it's grooves, I finally determined where I could remove the excess. I trimmed a chunk out about .250" in length, which left the edges of the gasket butting with each other just perfectly. I put Permatex in the cut area, followed by a tiny dab to JUST bring the sealing dab a tiny bit above the sealing surface. I then put the cover back on, gently tightened the bolts back down, and torqued them in sequence over the entire cover. No leaks after this. This "Swirly Google" gasket is yet another example of engineers being able to use fancy computers to make things FAR more complicated and less reliable than they needed to be. If you examine the cover, you can see that if they had moved the sealing surface out by .250" in each dimension, the gasket cover could have been sealed with a simple flat rectangular cork gasket, with a light layer of sealer on it, and it would probably have lasted the life of the vehicle.

I still REALLY LIKE MY CROSSFIRE! But this is the absolute first car in my entire life, that I had to rebuild the front suspension completely at 100K miles! And not only rebuild it by replacing nearly every component, but then had to spend additional money, JUST TO GET THE FRONT SUSPENSION TO ADJUST PROPERLY, SINCE THEY KNEW AT THE FACTORY WHEN THEY BUILT THE CAR THAT THE CAMBER BOLTS WERE INCORRECT FOR USE WITH THIS SUSPENSION SETUP AND NEVER COULD BE ADJUSTED TO GIVE MAXIMUM TIRE LIFE - AND THEY WENT AHEAD AND DID IT ANYWAY!

It is hard to believe the exceptionally poor engineering that is embodied in this car. The only car I have ever owned that matched it for maintenance demands is the Jaguar XK-8, which I also love, but I have forgiven it's mechanical sins because it is both incredibly beautiful, and joy to drive, and also it is British, so I knew what I was getting into when I bought it. Frankly, when I bought this car, I expected to be blown away by it's technical excellence. This thing is actually about on a level with a Yugo for engineering. From a 1952 Pontiac, to a 1970 AMC Rebel, a 1979 Ford Mustang with a 302 V-8, A Dodge Caravan, TWO Saturn SC-2's, a Chevy Corsica, and a 1982 GMC pickup,, NONE of them ever needed a front suspension rebuild,, just an alignment every 3-4 years at $29.95 per, and NONE of them ever had a valve cover gasket leak. REALLY? WTF!?!? They couldn't even design a valve cover that wouldn't leak? My faith in MB is severely shaken! And this was a FInal Iteration Engine, that should have had no bugs left in it! God help the people who bought cars with these engines when they first came out! They must have been REAL DOGS at that time!

Also, they should have painted their engines. This raw aluminum engine looks like a huge, corroded blob. When you remove the engine covers and fairings, it is a REALLY UGLY ENGINE! The Mercedes engine sculpture of the 1930's is long gone!

I must admit that the car has been pretty reliable. I have never yet been stuck by the side of the road. But THIS has only been possible by using this forum to stay ahead of problems as they develop, and nipping them in the bud. GREAT THANKS are due to ALL the members of this forum, for their commitment to keeping these cars on the road! It is only your tireless activities that have kept this vehicle alive and operating, and I must salute you!.

 

Thank you for the post, I need to replace my plugs and your account will be very helpful.
I already tried to remove the easily accessible passenger side front plug but didn't because it would not easily break free and I didn't want to break anything.
Need to get the freeze spray and special tools then I'll give it a try.

 

Remove and replace the plugs before you Can't !