Manual says change spark plugs after 5 years. Really?!
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From: NYC
2012 C300 4Matic
Manual says change spark plugs after 5 years. Really?!
My 05 only has 27k on it, but the manual says to change the plugs after 5 years regardless. Should I bother? Can anyone explain the thinking behind that?
My car does sometimes start up bad but I'm not sure if it's plug related. It doesn't take any longer than usual to start, but every so often when started it's a little shaky for the first 1-2 seconds like one of the cylinders is taking a moment to fire. After that there's a clicking noise for about 4 seconds that fades away. Happens on both hot and cold starts, but only about 25% of the time. No check engine light.
My car does sometimes start up bad but I'm not sure if it's plug related. It doesn't take any longer than usual to start, but every so often when started it's a little shaky for the first 1-2 seconds like one of the cylinders is taking a moment to fire. After that there's a clicking noise for about 4 seconds that fades away. Happens on both hot and cold starts, but only about 25% of the time. No check engine light.
Last edited by acr2001; Aug 26, 2009 at 03:23 PM.
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2019 G70 6MT & 2022 Ford Maverick XL
I thought originally that we had the same start issue, only my car did it on cold starts only. But mine has pretty much resolved itself with no action on my part and it never did it on hot starts anyway.
I would change them per the recommendation. 27,000 miles is low for a car that's been on the road for 5 years. Sometimes cars that are driven the least have the dirtiest engine components.
I would change them per the recommendation. 27,000 miles is low for a car that's been on the road for 5 years. Sometimes cars that are driven the least have the dirtiest engine components.
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2019 G70 6MT & 2022 Ford Maverick XL
Highway miles are better than city miles, thus a car with less miles doesn't mean it is in better shape. I drive my cars into the ground. I'm at 60k on my 05 and it had just 25k when I bought it last July.
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From: NYC
2012 C300 4Matic
Originally (I thought) my problem was only on cold starts, but the engine proved me wrong.
I just pulled a plug and to my untrained eye it looked pretty good. The insulator was still pretty white and I could still see the platinum on the ground electrode. Really not sure if I should replace them for over $100 in parts.
I just pulled a plug and to my untrained eye it looked pretty good. The insulator was still pretty white and I could still see the platinum on the ground electrode. Really not sure if I should replace them for over $100 in parts.
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From: Llandudno, Cape Town, South Africa
late 2009 CLK 350 Coupe Elegance, '65 Jaguar S Type wires
Changed my plugs at 45,000Km - 4 years. Made a big difference to stable idle & slightly spluttery cold starts. It all depends how long they run per trip in the self cleaning range. If you do a lot of short trips then change them. They can't be cleaned other than a 1000Km drive once fouled.
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2001 C240
I changed the spark plugs on my 2001 C240 in 2007. Only about 25,000 miles at the time, but the plugs were 6 years old . The car sometimes idled roughly, and most of my driving at the time was the hard New York city stop and go type. The new sparck plugs and fuel filter solved the rough idle problem.
I had the exact same symtoms on a 1981 Buick Regal, 1990 Honda Civic, and 1990 Toyota Celica with rough idle and hesitation during acceleration. Each time the problem was solved by installing new spark plugs, wires, distributor cap and rotor.
I had the exact same symtoms on a 1981 Buick Regal, 1990 Honda Civic, and 1990 Toyota Celica with rough idle and hesitation during acceleration. Each time the problem was solved by installing new spark plugs, wires, distributor cap and rotor.
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From: NYC
2012 C300 4Matic
Ok fine you guys convinced me. I'll let you know if I notice a difference. The idle is definitely rougher than it was when I bought it, but you can still barely feel that the engines running!
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From: Royal Oak, Michigan
Moped
i changed my plugs at 75,+++ miles. responds better but drinks gas more. lol. i switched from the OEM bosch to NGK iridium. from 32mpg to 24mpg(freeway). pretty big diffrence i know. i might switch back soon.. gas is going back up. lol.
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It sounds like you could have a problem that is more serious than spark plugs.
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From: Bangkok, Thailand
W124, W203, W204, W251
I just changed my plugs a few week ago with 54k on odo....it made a huge difference!
Engine runs smoother, more power and more MPG.
Still use the OEM Bosch.....only 5 bucks a piece and lucky for me M271 only takes 4.
Engine runs smoother, more power and more MPG.
Still use the OEM Bosch.....only 5 bucks a piece and lucky for me M271 only takes 4.
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From: WNY
2005 w203 C230
How hard was it to change them on the m271? I will be at the Dealer in a few days...maybe I should pick them up for our 2005...it has 44,000 miles and still gets a constant 29 mpg to the tank...
Thanks,
Jake
Thanks,
Jake
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From: Portland, Oregon
2016 GLE 350
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Jake, it's literally a 30 min. job on the m271. Only thing that could go wrong is cross-threading the plugs - just be careful (I turn the extension by hand until they're most of the way in). I think you also need a star socket to take the coil packs off, but that's it.
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From: NYC
2012 C300 4Matic
From what I gathered its sooo easy on the M271. But I don't think the M112 is as too bad after i removed a plug today. Other than being 4x the price 
It cost me $125 for 12 NGK double platinum plugs (same ones my car came from the factory with). I really hope I'm not wasting my time changing the plugs at 27k. Book says to do it and I do drive VERY hard and very short trips, so Glyn convinced me to change em.
It cost me $125 for 12 NGK double platinum plugs (same ones my car came from the factory with). I really hope I'm not wasting my time changing the plugs at 27k. Book says to do it and I do drive VERY hard and very short trips, so Glyn convinced me to change em.
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From: Bangkok, Thailand
W124, W203, W204, W251
How hard was it to change them on the m271? I will be at the Dealer in a few days...maybe I should pick them up for our 2005...it has 44,000 miles and still gets a constant 29 mpg to the tank...
-pop the engine cover off
-unscrew the coil packs
-unscrew the sparkplugs
-put new one on
-DONE!!!
Jake, it's literally a 30 min. job on the m271. Only thing that could go wrong is cross-threading the plugs - just be careful (I turn the extension by hand until they're most of the way in). I think you also need a star socket to take the coil packs off, but that's it.
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From: Llandudno, Cape Town, South Africa
late 2009 CLK 350 Coupe Elegance, '65 Jaguar S Type wires
You have a problem - Are you sure the NGKs are correct heat range & reach?
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Squeaked something fierce upon removal.
Suspect the time interval recommendation is to minimize effects of the galvanic reaction between the steel plug and the aluminum head, and the very real likelihood of thread damage were the task to be delayed longer than half a decade.
The business end of its OE iridium plugs were actually in fine condition. The placebo effect of improved performance helped the attendant bloody knuckles heal a little more quickly.
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From: WNY
2005 w203 C230
Was there any never-seize on the threads of the plugs? I will install a small amount on the upper threads when I re-install...I will do all of this work when I install the OEM block heater and pull out the threaded soft plug...
Thanks all!
Jake
Thanks all!
Jake
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From: ontario, Canada
C230 COUPE 2003 M271
I was able to take the coil packs off using an 8 or 10 mm standard socket. they arent in that tight so you dont necessarily need the star torx socket.
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From: Llandudno, Cape Town, South Africa
late 2009 CLK 350 Coupe Elegance, '65 Jaguar S Type wires
Swapped mine at ~50,000 - about five years after its build date.
Squeaked something fierce upon removal.
Suspect the time interval recommendation is to minimize effects of the galvanic reaction between the steel plug and the aluminum head, and the very real likelihood of thread damage were the task to be delayed longer than half a decade.
The business end of its OE iridium plugs were actually in fine condition. The placebo effect of improved performance helped the attendant bloody knuckles heal a little more quickly.
Squeaked something fierce upon removal.
Suspect the time interval recommendation is to minimize effects of the galvanic reaction between the steel plug and the aluminum head, and the very real likelihood of thread damage were the task to be delayed longer than half a decade.
The business end of its OE iridium plugs were actually in fine condition. The placebo effect of improved performance helped the attendant bloody knuckles heal a little more quickly.
