I have an 05 300c lava red .The car has 30000 miles and the check engine has come on and the dealer says its the spark plugs that are bad so the diadnostics are not included on the bill nor are the plugs. Is this common on these cars? this is the first new car where the plugs go out this soon! any comments would be appreciated.
dumb question
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joelatigo said:
Well spark plugs don't just "go bad" all the sudden, but the spark plug replacement interval in the owners manual is 30,000 miles. It seems suspect that the plugs caused your check engine light to go on, but I guess anything's possible since OBDII. It did kind of surprise me when I read that the spark plugs should be changed at 30k - - I mean 15 years ago that would have been fantastic but most cars now say 50k to 75k.
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That wouldn't be unheard of. MB used to hook up their O2 sensor lights to the odometer so that at 60k miles on the dot the light would come on.CottyGee said:
I decided to run this past my dad, who has owned a small chain of ASE certified independant repair shops for 25 years. He's not a technician, but he's gotten pretty good over the years... 
I lost the text of our conversation via IM, but basically he said that it would be very unusual to have JUST plugs go bad at 30K miles without something else being wrong. For example, if the car was for some reason running very lean (not enough fuel) and then driven hard for an extended period, that could damage the plugs.
He suggested asking for the used plugs. Assuming it's an ethical Service Department, that should tell you a great deal. (Almost certainly you can find pictures on the web to look compare to yours for every imaginable condition in which plugs are found...)
Having JUST the plugs go "bad" @ 30K would be very unlikely, and would seem to be MUCH more likely to be a "service opportunity" for the stealership... We'll see! If everybody starts having Check Engine lights come on @ 30K with nothing else wrong, that will be pretty telling!
I lost the text of our conversation via IM, but basically he said that it would be very unusual to have JUST plugs go bad at 30K miles without something else being wrong. For example, if the car was for some reason running very lean (not enough fuel) and then driven hard for an extended period, that could damage the plugs.
He suggested asking for the used plugs. Assuming it's an ethical Service Department, that should tell you a great deal. (Almost certainly you can find pictures on the web to look compare to yours for every imaginable condition in which plugs are found...)
Having JUST the plugs go "bad" @ 30K would be very unlikely, and would seem to be MUCH more likely to be a "service opportunity" for the stealership... We'll see! If everybody starts having Check Engine lights come on @ 30K with nothing else wrong, that will be pretty telling!
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Those plugs are not that easy to get to and there are 16 of those bad boys. A costly service item.
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did they tell you what the code is?
the check engine light is not designed to come on at 30k. I have worked on a few magnums and 300's with 30k on them and the light did not come on.
the check engine light is not designed to come on at 30k. I have worked on a few magnums and 300's with 30k on them and the light did not come on.
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Well they are related to emissions, but they are a normal maintenance item and the owners manual does specify a 30k mile replacement interval. I got no problem with that (although it surprised me that it wasn't longer) and I wouldn't expect it to be done at no charge. I would have a problem, however, with the dealer charging me to "diagnose" this... I mean if my check engine light came on I'd assume something was wrong and since I'm still under warranty I'd go to the dealer. They should not charge for the 'diagnosis' and turn the light off for no charge, and then give him the option of having them change the plugs or not......toothdoc said:
EXCEPT that the 100K interval ended up causing problems. In that time period, it's not unusual to have something happen that damages a plug or plugs. I've heard stories of plugs where the electrode got burned so far up into the plug that it ended up actually WELDED to the head!Model 57 said:
Needless to say, folks that thought they needed new plugs were not very happy when told they needed a new $2,000+ head!!!
I've got no problem with the 30K interval, tho it is a surprisingly short interval. But I agree that IF the light comes on automatically @ 30K, that the stealership should tell you that at no charge. (There's really no diagnosis required when you KNOW the light comes on when the odometer passes 30K!)
dunmd question
thanks for all the feed back
the dealer says because the plugs caused the light to go on the diagnostics performed on the car are not covered $91.00. they would gladley change them out for $200.55, also they want to do an injector flush for $169.95, pcv valve $ 57.97 airfilter $35 and rotate and balance my tires 49.05 for a grand total of $600.23 with tax :fing26: ! no i did not get this done i paid the $91.00 bought the plugs from the service dept. and was going to install them last night but they gave me the wrong plugs! the plugs are so easy to remove that it took me about 15 min to remove all 8 plugs the air filter i bought for $12.99 at autozone and i picked up a bottle of injector cleaner and and throtle body cleaner. i am just waiting for plugs to see if this changes any thing.
thanks for all the feed back
the dealer says because the plugs caused the light to go on the diagnostics performed on the car are not covered $91.00. they would gladley change them out for $200.55, also they want to do an injector flush for $169.95, pcv valve $ 57.97 airfilter $35 and rotate and balance my tires 49.05 for a grand total of $600.23 with tax :fing26: ! no i did not get this done i paid the $91.00 bought the plugs from the service dept. and was going to install them last night but they gave me the wrong plugs! the plugs are so easy to remove that it took me about 15 min to remove all 8 plugs the air filter i bought for $12.99 at autozone and i picked up a bottle of injector cleaner and and throtle body cleaner. i am just waiting for plugs to see if this changes any thing.
All sounds good. Hope you didn't buy Fram anything. Fram is horrid stuff, for an absolute fact.
The injector cleaner and throttle body cleaner shouldn't do any harm, but they also won't really do the job they're advertised to do. The throttle body needs to be taken off and manually cleaned - not sure about what cleaners are used, since I always have this done by a pro. And the injectors need to be cleaned using an injector cleaning machine, like the MotorVac system.
I thought there were 16 plugs on the HEMI 5.7. ??
Try taking your car to an ASE Certified independent repair facility that is a member of the Better Business Buereu with a clean record and employes ASE Certified technicians and at least one ASE Certified Master Mechanic at each location. You can also find a shop by looking at AAA - you know, (Triple A).
Oops - forgot to say the independent garage should be able to do the throttle body and fuel injector service for ya at a cost MUCH more reasonable than the stealership...
The injector cleaner and throttle body cleaner shouldn't do any harm, but they also won't really do the job they're advertised to do. The throttle body needs to be taken off and manually cleaned - not sure about what cleaners are used, since I always have this done by a pro. And the injectors need to be cleaned using an injector cleaning machine, like the MotorVac system.
I thought there were 16 plugs on the HEMI 5.7. ??
Try taking your car to an ASE Certified independent repair facility that is a member of the Better Business Buereu with a clean record and employes ASE Certified technicians and at least one ASE Certified Master Mechanic at each location. You can also find a shop by looking at AAA - you know, (Triple A).
Oops - forgot to say the independent garage should be able to do the throttle body and fuel injector service for ya at a cost MUCH more reasonable than the stealership...
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I don't think having the throttle body cleaned needs to be done as general maintenance. It only needs to be done once things start sticking (if they ever do, my MB has 150k miles and no throttle body issues, our Olds started to stick after 70, independant tech cleaned it up good as new). Injector cleaner isn't really necessary, but I disagree that it can't hurt. STP has had issues gunking up fuel distributors in the past (does the 5.7 use a fuel rail?). Chevron's Techron is probably the most respected name in the fuel additive business, and I know it works, though sometimes the first application won't totally clean everything. Then, I only use it when it's obvious I need it. You want to use it before you change your oil.
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