2015 C 300 Spark Plugs at 50K miles?
 

Just had the 50K service A done on my 2015 C300.
Dealer recommended changing spark plugs for $550. When I pushed for details, the breakdown was $100 for 4 spark plugs ( Q-4-15-0038) and 2.5 hrs of labor.

Has anyone else replaced the plugs at 50K miles and what was the cost? I thought spark plugs had a much longer life than 50K miles..

I haven't done it, my car is only at 7K miles, but at that price you need to find an indy to do these jobs. It'll be far cheaper.

There's no way it take 2.5 hrs to do spark plugs on a inline 4. Take it to a indie or have a friend do it.

that's about right. I paid 840$ for 50k service with spark plugs replaced at dealer.

Completely agree. Changing spark plugs on an inline 4 is as straight forward as it gets. V6s on the other hand can be tricky and it's worth it sometimes to pay a shop to do it. The torque spec for the C300 is 23nm for those wondering.

Did the plugs look like they needed to be changed at 50,000 miles?

Im also in the bay area may I ask which MB dealer, quotes I been getting is like $1200-$1400 I know thats high. thanks

Mercedes of Walnut Creek, they actually have a printout and on the computer showing 50k service with spark plug replacement, 846$. so there' no BS.
on my work order sheet, spark plugs part and labor is 452$, very reasonable.
i have went to this Fremont dealer, this adviser just pull some numbers out of his ass, he said 50k service is 1000$ +, spark plug is 600$ +.
for future reference, i just done 60k service on my 2016 C450 with transmission oil change, 1248$.

look at other bayarea website, this other dealer have a service special, spend 800$ - 1099$, get 128$ off.
bring this coupon or mention it to them, they will match the coupon.
My adviser is Carlos Ramos, tell them Mr. Li send you. he'll know. :)

I replaced mine at 58K. Didn't go to MB dealership. I'm also in the Bay Area.

Alex

Spark plugs
 

Probably would not hurt. Engines running under boost tend to go through them quicker. What does the manual say?

Spark plugs
 

To the post on prepaid maintenance - yes - that covers spark plug job...

Support your local independent shop!
 

With my first MB (The 2007 C280 pictured in my Signature), I went to an independent shop after my first "A" service. That "A" service was at the dealer where I bought the car. At the time, they were the only dealer in the western suburbs of Boston. They treated me like I was a rich customer of a private bank, but they did things like charge me $7, plus a labor charge for "refilling" a windshield wiper fluid reservoir that was almost completely full. My present 2015 C300 (bought at a new dealership competitor of the first dealer) came with two years worth of services as part of the purchase agreement.

With those "free" "A" and "B" services out of the way, I have gone back to my independent shop. It doesn't hurt that the shop is almost in walking distance of my home and that the manager is the President of the local chapter of the Mercedes-Benz Club of America (and a financial supporter of the club). Remember, these shops exist because the dealerships CAN'T repair the "B.C." (Before Computers) vehicles. They don't want to spend money on real mechanics. They employ only "technicians," who replace Part A when the on-board computer throws Code X.

At what mileage is it recommended to change spark plugs on a C400? Thanks.

currently have my '16 C450 in for 50k mile service. They also recommended replacing the spark plugs and quoted me $700 for that. They said the engine filters would be another $185 on top of the "A" service which does not include this? The C450 does have 2 Engine filters, but c'mon.

https://www.mbusa.com/vcm/MB/Digital...nce_manual.pdf

C400 and other 3.0TT motors should be at 46k miles. I wouldn't push too much past mileage, the new mercedes motors uses a waste spark fire where the plug fires up to 5 times per piston stroke which puts a lot more use on the plugs (and coils) than say a toyota w/100k mile interval. Even the ML350 has the same interval, and its not forced induction.
Get the OEM plugs online and DIY. Not much to it on the W205 I4/V6 assuming you have done plugs on other cars before. C63 might be more PITA, not sure how far back the last 2 plugs are.

I get the occasional stumble on restart from the auto-stop system. Think plugs could make a difference on that? C300 @ ~36k miles, 99% of the time filled with Shell or Exxon 93.

$850 to replace spark plugs!! :eek::crazy:

I did spark plugs on this car. Pretty easy. Nothing special, just make sure you use some anti seize on the new plugs and all should be good. oh and check the gap on the new plugs as well. I think I will do the plugs every year or 2 just because it felt a little better after I did them and the fuel economy may have went up and it was so easy...
$100 would be a lot for a spark plug change on this car, anything more is just absurd.

Some MBZ engines have very 'sensitive' ignition systems. The 2-plug/cyl engines are especially critical. The 'misfire detection' circuitry uses a 1000 volt current passed through the spark plug gap AFTER the end of combustion. The current flow is a function of 'ionized gas' in the cylinder, which correlates to combustion completeness.

The 30,000 'firing' voltage is actually 'pulsed' many times at high frequency each power stroke with the number of sparks calculated to provide continual sparking for so many crankshaft degrees of rotation (piston height in the cylinder)

The silicone 'rubber' insulator inside the spark plug connector should be carefully inspected or simply replaced every time it is removed. The high frequency 30,000 volt spark pulse will jump through any defect-even if it is not visible, and cause 'misfire detected' CEL.

IMHO, more 'misfire detected' codes are caused by insulator/plug connectors defects than everything else combined. At 100,000 miles, the spark plug 'gaps' will look and measure and perform 'as new', The iridium electrodes do not wear. The silicone rubber insulators DO AGE and fail.

I just had mine changed at an Independent shop. I bought 4 OEM (NKG) plugs at FCPEuro for $45. Labor was one hour at $121.50.

save your $, go to an Indy.

My dealer (Pleasanton CA) was quoting $1800 for a 50k service on a GLS. I had him do the A service instead ($199, which is still 2x higher than indy shop) as I'm not quite at 50k.

Do you really have to change Mercedes spark plugs at 50k? That seems really low compared to BMW and others that go 100k.