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Grammar **** or no, (though, not sure how grammar and German National Socialism apply here), one of the very few things we actually have to go on when on line, is how someone writes. You know, spelling, grammar, punctuation... homophones, all that fun stuff.
I don’t know you personally — for all I know, you could be a Nobel laureate or someone arguing with their toaster and losing badly. But since I can’t see you, hear you, or shake your hand, I’m left to make assumptions based on how you string your words together.
So fair or not, your writing becomes your handshake, your face, and your resume — all rolled into one. And yes, style matters. Whether you meant to or not, you’re saying something about yourself every time you hit “post.”
As far as getting advice from you... please forgive me if I pass of your "advice", present or future.
Grammar **** or no, (though, not sure how grammar and German National Socialism apply here), one of the very few things we actually have to go on when on line, is how someone writes. You know, spelling, grammar, punctuation... homophones, all that fun stuff.
I don’t know you personally — for all I know, you could be a Nobel laureate or someone arguing with their toaster and losing badly. But since I can’t see you, hear you, or shake your hand, I’m left to make assumptions based on how you string your words together.
So fair or not, your writing becomes your handshake, your face, and your resume — all rolled into one. And yes, style matters. Whether you meant to or not, you’re saying something about yourself every time you hit “post.”
As far as getting advice from you... please forgive me if I pass of your "advice", present or future.
So my initial thoughts on you were proven to be correct, thanks for the confirmation
2023 E 450 Sedan. 2018 GLC 300. 2013 E 350 Coupe (retired)
I like ebay. I go by the number of ratings and the percent positive. I don't like to go under 98 percent. Sometimes the items come from China. I have not had any problems yet. I would buy bosch on eBay, as i think it is taking more of a chance when they claim mercedes, but IDK.
Spark plugs on M273/276 are barely more difficult than an oil change if you have access to the right tools (star bits and a torque wrench being the most exotic). More comfortable than an oil change for sure. If you really want to do your ignition system a favor, swap out the coils while you're in there. I don't know about the later turbocharged engines, as I haven't messed around with them, but it would be pretty unusual for the engineers to completely ignore serviceability on something so simple and mission critical.
As has been pointed out, Mercedes does not make spark plugs (to be honest, I haven't dug too deep on this with Mercedes in particular, but under the current manufacturing paradigm, that's usually limited to engines, sheet metal, and assembly; any deviations from this formula will be nit picky and minimal), they contract it out to a handful of quality manufacturers. This is not a secret. The suppliers are not a secret. It's not a conspiracy, just business. Buy the same spec from one of the OEMs, live with the fact that there's not a star hiding deep in your engine where one could have been, and save money. $30X8 is a very nice dinner for once you've finished the job, showered, and changed into a clean pair of clothes. I did mine a while back (coils and air filter too) in an unremarkably brief amount of time with whatever OEM supplier's plugs were cheapest at the time (it's really that simple, don't overthink it), and there have been zero issues.
Interesting about that MB plug being an NGK PLKR6A. If that in fact is a Genuine MB plug from the dealer then I see no reason to not use just a regular NGK PLKR6A plug since they should be the same things minus the MB stamp.
I never noticed the NGK PLKR6A plug is 1k and the Bosch YR7MPP33 is 6k, I thought they were both 6k which is why I never bothered to look further into NGK.
For the M272 plugs the dealer price isnt that bad at all, I look up the NGK PLKR6A plugs at local auto stores and they want more money than the MB dealer wants for Genuine plugs. Same with the battery, when I was looking for a replacement all the local auto stores wanted more money so I ended up at the MB dealer. Afterwards I realized Walmart carries H7 agm batteries in stock cheaper with a longer warranty so i'd probably go there next time.
I was searching around online for the specs on the Bosch Y7MPP33 ( not YR7MPP33) plug and cannot find anything on them. Wonder if they are 1k, or even 0.
In my search I came across some inexpensive MB Bosch plugs. Im guessing this is why they are so cheap on places like ebay. It says Y7mpp33 but in the photos im seeing an "R" in the numbers.
Spark plugs on M273/276 are barely more difficult than an oil change if you have access to the right tools (star bits and a torque wrench being the most exotic). More comfortable than an oil change for sure. If you really want to do your ignition system a favor, swap out the coils while you're in there. I don't know about the later turbocharged engines, as I haven't messed around with them, but it would be pretty unusual for the engineers to completely ignore serviceability on something so simple and mission critical.
As has been pointed out, Mercedes does not make spark plugs (to be honest, I haven't dug too deep on this with Mercedes in particular, but under the current manufacturing paradigm, that's usually limited to engines, sheet metal, and assembly; any deviations from this formula will be nit picky and minimal), they contract it out to a handful of quality manufacturers. This is not a secret. The suppliers are not a secret. It's not a conspiracy, just business. Buy the same spec from one of the OEMs, live with the fact that there's not a star hiding deep in your engine where one could have been, and save money. $30X8 is a very nice dinner for once you've finished the job, showered, and changed into a clean pair of clothes. I did mine a while back (coils and air filter too) in an unremarkably brief amount of time with whatever OEM supplier's plugs were cheapest at the time (it's really that simple, don't overthink it), and there have been zero issues.
Yes, but this is not about whether they are genuine Mercedes with their logo, it's about getting the correct spark plus for your car, flex fuel cars take different plugs than non-flex fuel cars, they are different plugs with different heat ranges and resistance, I understand that may make no difference for a 9 plus year old car with likely 100k miles, to some
Last edited by pierrejoliat; Jul 19, 2025 at 02:56 PM.
This thread highlights how easy it is to get bad ignition sparkplugs.
> TRUSTED PARTS
1 -- The most compatible parts are genuine MB stamped. They get QA'ed by batches to get distributed in a trueted supply-chain.
2 -- The next best option is the genuine OE Bosch or NGK as applicable for your engine type.
Outside that... misc questionable copies are best left alone for someone else to waste time.
> IGNITION JOB TEST...
When installation is all done, it's up to us to make sure we do not get any misfires.
It's easy to know: pay attention to your engine VIBRATIONS, this is how well it's running.
The plug-boot has a carbon pile resistor built-in. It is fragile and best replaced with plugs at 50kMi.
Longer service intervals will back fire spark inside the coil to breach them. Don't let that happen.
> MISFIRE TIPS
Of course MB misfires are not only spark related but lean mixture & engine timing related.
Do not rush to waste money on injector sets to cure lean misfires: lol!
The first step is to trust you have reliable ignition from genuine parts. All cyl. must spark identically.
From there ECU may hand out more fuel that will get burned properly based on Lambda's feedback. This explains why there are many types of misfires!! Not simply bad ignition parts.
The hard part is to get strong mixtures for pressure sensitive throttle + zero vibrations.
This is made available by tweaked setup:
sparks (ignition / gap)
mixture (historical maps)
timings (frictions / spark / CAN)
pressures (oil /cylinders)
voltage (chassis / coils)
heat (coolant / oil / tranny)
Each item you help improve earns power reward away from lean misfires.
Last edited by CaliBenzDriver; Jul 19, 2025 at 05:40 PM.
Interesting note about the different plugs for the M276 with Ethanol/Flex Fuel options.
I have the 272.948 engine and see no such option with plugs on FCP. My engine is a PZEV and I dont see any label on the fuel door about E85 and theres no option code 929 on the build sheet.
I was going to stop by the MB dealer and ask to see a plug but was lazy and wrote to FCP asking. I wanted to know because if I ordered the Genuine Mercedes plugs but they ended up being the Bosch YR7MPP33 with a Mercedes logo id be mad, would have just bought the cheaper Bosch plugs instead.
I had the MB part # and the listing on FCP was the correct ones, I just wanted to see what they would send me if I ordered from them. Was hoping they walked into the warehouse and physically looked at the plugs they have in stock.
When I was replacing my belt and tensioner my operators manual lists the size as 2401mm. The closest I could find was a Continental 6K2404 which fits great. The MB belt says 2397. Then I was looking at photos of the Genuine MB tensioner and noticed its stamped gates on the back so I bought a Gates brand and it looks the same. I paid around $62 for the Gates and the MB was over $200. Someone on here bought a Febi tensioner and shared a photo and it was a Gates also.
I bought them from eEuroparts. Bought a few things from when I found the prices lower. I paid $14 for the belt 2yrs ago and just looked and its only $11 now.
I conducted several Merc dealer parts lookups, and it appeared they were all using the same software. I entered my car info, 2016, E350, Base, Gasoline, and asked for the spark plug. It couldn't find anything. Tried spark plug boot and got a hex bolt, asked for a spark plug connector and same reply as the spark plug. Well, I just don't know what to think about parts lookup on Merc dealer parts lookup websites. Maybe tomorrow will be better.
I conducted several Merc dealer parts lookups, and it appeared they were all using the same software. I entered my car info, 2016, E350, Base, Gasoline, and asked for the spark plug. It couldn't find anything. Tried spark plug boot and got a hex bolt, asked for a spark plug connector and same reply as the spark plug. Well, I just don't know what to think about parts lookup on Merc dealer parts lookup websites. Maybe tomorrow will be better.
- try to switch different years and survey results for your engine type -
- there are not tons of different plugs given one engine non flex-fuel
Have you tried to search by VIN#: It's the most specific.
MB Indonesia told me MB HQ stop selling COP boots.
That means MB HQ does not want to sell it stand alone, must buy entire COP.
=========
On a side note :
My M276 spark plug genuine MB , its resistance is 1.368 Kilo ohms, not 1K ohm. I measured cylinder #1, me too lazy to measure the rest.
All 6 are new when in June 2021, and today 21st July 2025 is only 12,000KM driven.
I replaced the previous set after 10,000 KM to 31,000KM.
I like my plugs to do no more than 25,000KM. Thus 20,000KM ish I replace them.
The clean one 3rd from the left is the new one, 1 to 3 is the one serving 21,000KM
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====== RESISTANCE TEST ===============
Guess what Bosch spec wrote .........
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Look below : supposedly NO RESISTOR
When MB buys spark plugs and they want custom spec resistor, they get it. They buy millions of spark plugs.
Resistor on a spark plug is important for our massively laden computers on board.
MB choosen approx 1.4K ohms as their magic number, who is there to argue ??
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Never underestimate how an-al German engineers can be and with such buying power BMW or MB can do for components.
It is all abour $$ and priority.
As I said, some components you can go for BOSCH or other actual OE supplier of MB cars of your model.
Spark Plugs , get MB genuine. As easy as that.
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Why is are there resistors built into modern plugs?
The resistance values built into modern plugs have nothing to do with whether the engine runs on flex fuel, non flex fuel, unicorn urine (yeah, I know, already used that once today). The resistance is there for EMI shielding. The EMI generated by a non resistor (shielded) plug can interfere with wireless signals, onboard CANBus systems and even wiring.
The added or reduced resistance has no effect on the spark itself, it just slows down the rise time of the spark pulse, thereby reducing that aforementioned EMI.
In high performance systems, that resistance is easily compensated for by the ignition system. Modern ignition systems can even vary the output voltage in real time, to compensate for varying amounts of fuel being injected into the combustion chambers. We're not dealing with our grand papy's 1960's single coil with individual wires going to each plug, ignition designs anymore.
Should you run non resistor plugs in modern applications? No. Can you? Sure, though you may get diminished performance due to EMI issues. Again the resistor just dampens the rise of voltageand suppresses EMI, not limit current like a fuse would. The spark is essentially the same between the two versions.
Correct as always Surya,resistance has a direct effect on spark, High resistance effects spark quality, if the resistance is too high, it changes the intensity and duration of the spark, which can cause misfires, poor combustion and reduced power output, too low resistance also effects spark quality, which can cause too intense of a spark and pre-ignition, which leads to engine damage
Last edited by pierrejoliat; Jul 21, 2025 at 01:22 PM.
Mercedes SLR McLaren 722 S Is Extremely Rare Example Modified by McLaren
Slideshow: A one-of-one U.S.-spec Mercedes-Benz SLR McLaren Roadster became even rarer after a factory-backed transformation at McLaren's headquarters.
