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When I bought a set of MB OE plugs for my G550 (M176), they had NGK p/n's etched on them. The NGK plug was about $2 cheaper, and Bosch was about $8 less as I recall.
I called NGK, they told me the correct spark plug for my car is SILZKFR8G7S (old part number is SILZKFR8D7S).
On ebay, there are still heaps of old part SILZKFR8D7S still out there
Can you pls show us both firing tips side by side of your genuine Bosch vs. genuine NGK.
I assume double-Iridium needles ??
How fine vs. stuby is the tip design??
FYI: make sure not to buy your plugs from eB or Amz... most are COUNTERFEITS look-alikes.
I really like the job sparkplugs do.
Last edited by CaliBenzDriver; Mar 25, 2026 at 08:45 PM.
Sorry, I don't have them to show you as I am looking to buy those for my first time servicing my Merc (newbie). That is why I called NGK for the sparkplug suitable for my car.
I am looking around to buy them. Below are what I intend to buy
I called NGK, they told me the correct spark plug for my car is SILZKFR8G7S (old part number is SILZKFR8D7S).
On ebay, there are still heaps of old part SILZKFR8D7S still out there
Dude... You're going to save what? $8-$10 on a few spark plugs and for what? to gamble if they're real or not? Just go to MB and buy them at the parts counter. Or buy them from https://www.mbpartsource.com/ if you're not wanting to spend that much on genuine parts.
Honestly, you shouldn't be doing this job in my opinion if you're going to be cheaping out on parts. Just pay someone to do it for you with correct materials. You're probably doing this your self to save money (which you already are if you're not paying someone else to do the labor for you) and because you won't have to pay the mark up price on parts anyways from your mechanic. So just pay the OEM part and do the job. Buy them from FCP Euro where you'll get a lifetime warranty.
Sorry all, I think it is misunderstanding some where in my post. I never look for saving few bucks. I just want to get the right parts. I have been using NGK for all my cars. So I trust NGK, whether they are less (or more) expensive.
I went to FCP Euro and it shows the old obsolete NGK SILZKFR8D7SMercedes-Benz E400 Parts | FCP Euro. I really don't want to buy the old stock. I want the newer (or update) NGK SILZKFR8G7S (even it is more expensive - I don't mind)
I search around and found those on ebay and asked for confirmation if they are fake.
I took your and CaliBen advice of not getting from ebay. So I just went ahead and order from RockAuto More Information for NGK 96427
Though that I am new to Merc, but I think these normal servicing like brake, spark plugs, shouldn't be too hard (or may be it is), I feel more satisfaction if I can DIY for these sort of doable work.
Last edited by spacemaster; Mar 26, 2026 at 01:12 AM.
Sorry all, I think it is misunderstanding some where in my post. I never look for saving few bucks. I just want to get the right parts. I have been using NGK for all my cars. So I trust NGK, whether they are less (or more) expensive.
I went to FCP Euro and it shows the old obsolete NGK SILZKFR8D7SMercedes-Benz E400 Parts | FCP Euro. I really don't want to buy the old stock. I want the newer (or update) NGK SILZKFR8G7S (even it is more expensive - I don't mind)
I search around and found those on ebay and asked for confirmation if they are fake.
I took your and CaliBen advice of not getting from ebay. So I just went ahead and order from RockAuto More Information for NGK 96427
Though that I am new to Merc, but I think these normal servicing like brake, spark plugs, shouldn't be too hard (or may be it is), I feel more satisfaction if I can DIY for these sort of doable work.
If that's the case, when it comes to components like spark plugs, the only right parts are from Mercedes. You can replace your fuel injectors with Bosch, you can replace your suspension components with the OE supplier, timing chain with IWIS, etc. But spark plugs seem to be one of those things that have to be right and 100%. MB is the only way to go for them and for a piece of mind.
You should also get a thin walled deep socket with a magnet to help you extract your spark plugs, else you'll be having fun removing them and trying to pull them out of the spark plug holes.
No question that NGK makes the best plug (which is why MB OEMs from NGK). My G550's plug is an MB A000 159 05 00, and has the NGK p/n SILZKFR8F7S etched on it. Bought them from AutohausAZ in September 2025 for $22/ea.
No question that NGK makes the best plug (which is why MB OEMs from NGK). My G550's plug is an MB A000 159 05 00, and has the NGK p/n SILZKFR8F7S etched on it. Bought them from AutohausAZ in September 2025 for $22/ea.
how does the firing end look ??
NGK is known for not compromising with quality... real copper crush-washers!
Last edited by CaliBenzDriver; Mar 26, 2026 at 04:45 PM.
NGK's ILFR6A-6 spark plugs seem to be a decent equivalent to the OEM Mercedes-Benz spark plugs, at least from what I've heard from a few folks who've made the swap in their 2022 GLEs and GLSs. From what I gather, the 6.0 and 6.5mm spark plug gaps also match the OEM spec.
@AlexMonroe75 there's also the issue with making sure that they are properly clocked. With standard Mercedes OEM plugs you can be assured that if the plug is properly torqued first time it is properly clocked. If you remove the plug and put it back in your torque spec is off because the pressure washer is already crushed.
NGK's ILFR6A-6 spark plugs seem to be a decent equivalent to the OEM Mercedes-Benz spark plugs, at least from what I've heard from a few folks who've made the swap in their 2022 GLEs and GLSs. From what I gather, the 6.0 and 6.5mm spark plug gaps also match the OEM spec.
If that's the case, when it comes to components like spark plugs, the only right parts are from Mercedes. You can replace your fuel injectors with Bosch, you can replace your suspension components with the OE supplier, timing chain with IWIS, etc. But spark plugs seem to be one of those things that have to be right and 100%. MB is the only way to go for them and for a piece of mind.
You should also get a thin walled deep socket with a magnet to help you extract your spark plugs, else you'll be having fun removing them and trying to pull them out of the spark plug holes.
Oh, interesting... Didn't know about the thin wall.
Just check on my 14mm 12pt spark plug socket. It has outer diameter = 22mm. Do you think it will fit ?
Last edited by spacemaster; Mar 27, 2026 at 03:25 AM.
I took your and CaliBen advice of not getting from ebay. So I just went ahead and order from RockAuto More Information for NGK 96427
Excellent choice. Those are the plugs (NGK) I use in my M276 3.0L turbo. I also buy mine from RockAuto. I didn’t know they ship overseas. Interestingly, my M276 3.5L non-turbo uses different plugs (Bosch). But that engine is also built for flex fuel, so I don’t know if that makes a difference.
Many of these plugs look similar besides the flat top for flex fuel.
They are built pre-indexed, temperature may be different, thread length may be different, tip may be different...
Unfortunately it's not easy to cross Bosch plugs into NGK's. I'd be willing to switch brand in 10 to 15kMi. around 100k service.
Both the Bosch and NGK are identified as OE plugs, meaning they are exactly the same as genuine Mercedes plugs, but without the Mercedes star. I run NGKs in my turbo car and the Bosch in my non-turbo car. Personally, I found the NGKs to index better than the Bosch plugs in one car and the Bosch were fine in the other.
Both the Bosch and NGK are identified as OE plugs, meaning they are exactly the same as genuine Mercedes plugs, but without the Mercedes star.
I run NGKs in my turbo car and the Bosch in my non-turbo car.
Personally, I found the NGKs to index better than the Bosch plugs in one car and the Bosch were fine in the other.
At 50k.Mi mark I failed to source NGK's to upgrade my factory mounted plugs. So I had to use Bosch plugs I had to file metal burrs off the GND strap. Genuine NIB Bosch.
How can I successfully X-Ref genuine MB from Bosch into premium NGK ??
I think their firing tip is a bit more effective.... I want to test it.
Around 50k.Mi my engine was already running poorly compared to now at 80k.Mi.
So now I'll be able to tell right away what fires better/worse...
From experience I can almost bet "stubby iridium" electrode fires better than center "needle iridium".
NGK (MY'18 3.0TT) - Courtesy RockAuto dot com
Bosch shows approximative firing geometry
Both the above sales pictures look like they feature similar stubbly iridium pelet.
Last edited by CaliBenzDriver; Mar 28, 2026 at 12:34 AM.
At 50k.Mi mark I failed to source NGK's to upgrade my factory mounted plugs. So I had to use Bosch plugs I had to file metal burrs off the GND strap. Genuine NIB Bosch.
How can I successfully X-Ref genuine MB from Bosch into premium NGK ??
I think their firing tip is a bit more effective.... I want to test it.
Around 50k.Mi my engine was already running poorly compared to now at 80k.Mi.
So now I'll be able to tell right away what fires better/worse...
From experience I can almost bet "stubby iridium" electrode fires better than center "needle iridium".
NGK (MY'18 3.0TT) - Courtesy RockAuto dot com
Bosch shows approximative firing geometry
Both the above sales pictures look like they feature similar stubbly iridium pelet.
I also have an engine like yours, but mine is built for flex fuel. However, according to the EPC, both car engines (flex and non-flex) use the same plugs (A0041596903). I just found in my particular case, the NGKs indexed better than the Bosch plugs. I had gotten the Bosch plugs from FCP Euro and actually returned them as defective because they would not all index within limits.
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