Ok, gotcha. I thought you changed the coils but reused the old boots. It might be possible that @Katie22 and I were thinking alike and misunderstood you.

 

I have a 2018 S560. I bought it with 39,000 miles back in April 2025. When purchasing, I saw ignition coil replacement in the maintenance records 6 months prior in November 2024 with about 38,000 miles. It surprised me that it needed coil replacement with low mileage so I asked the service department about it. They let me know that the coils received an extended warranty of 15 years / 150k miles due to their higher than expected failure rate, which gave me reassurance. After owning the car for 2 months and putting about 2,000 miles on it, I got a flashing check engine light and low frequency vibration under throttle while driving down the freeway. Immediately I thought about the coil issue due to what I’d learned and what seemed to feel like it was running on 7 cylinders. I coasted off the freeway to a parking lot and shut the engine down. Gave it a couple minutes and restarted. The check engine light and vibration were no longer present after restart and I was able to continue my drive. I scheduled an appointment with MB service for a week later but continued to drive the car without issue until the appointment. Literally a quarter mile from the service center on my way to the appointment the engine light a vibration coincidentally returned, perfect timing really (pun intended), so I was able to drop the car off with the issue currently occurring after having gone away for the previous week after shutting down and restarting. MB service replaced my #5 & 6 coil pack (they come in pairs) and replaced #5 spark plug as is had become fouled due to the misfire from failed coil #5. MB replaced the coil pack and the fouled plug for no change under warranty. So I am thinking I should now have 4 of the original 8 coils replaced (2 with replaced coil pack before I bought the car and 2 with the pack replaced after I bought it). According to my service center and chatGPT, the replacement coils are improved compared to the original coils, so my hope is the replaced coils will last much much longer. I hope my remaining 4 original coils hold up, but it’s good to know they are under warranty until 2033 and another 100k+ miles for me. I just hope none of those original 4 fail on me in the middle of a
long trip!! @trigital

 

you are the first to mention an extended warranty on faulty coils. I looked it up..it covers certain ‘18-‘19 models.

 

Do you have the specifics around the warranty extension for the coil packs? I'd love to see it, and possibly use it in the future. Where can this be found?

 

I just googled it..
best bet is to call around to the Mercedes Dealerships.
would be interesting to see if you get the same answer from each dealer.

 

I learned about the warranty before I bought the car from the service center at the dealership I bought it from in Littleton Colorado. Then after I bought it, my local dealership in Farmington Utah confirmed it and they are the ones that did the replacement for me under warranty.

 

ChatGPT says: Mercedes‑Benz USA does indeed have an extended warranty (not a recall) covering defective ignition coils/coil‑packs on the 2018 S 560, particularly for the M177/M178 V8 engine—but there is no published campaign number or official Service Action number available publicly.It recommends contacting an authorized Mercedes‑Benz dealership and request a VIN‑specific DCS‑net warranty inquiry, and asking them to check for “ignition coil limited warranty extension” for your vehicle’s VIN (especially for the M177/M178 V8 engines).

 

Good stuff Ryan.
Doesn’t apply to my ‘15 W222, but great info for our ‘18-‘19 members.

 

Just had my car at my indy yesterday for 2 more failing coil packs. Interestingly, he told me to expect the newer (Bosch) coil packs to fail sooner than the factory installed originals did. Has anybody else had this experience?

 

Dave, what symptoms or codes did you experience that led to the coil replacement?

 

Wow! That’s not good to hear. It’s surprising to me coils aren’t something the can make last the life of the car.

 

Car would start running extremely rough and the CEL started flashing. I have to put my code reader on it while the car is still running with the CEL in order to get the codes. As soon as I would shut off the car and restart it, the car would run normally with no CEL and there are no more codes showing up. The codes aren't even saved in memory where MB can read them. I've now had 5 coil packs go bad in the last year, with 4 of them in the last 4 months. Once the CEL comes on once, it will come on again within a week with the same code, so I know they're going bad. Spark plugs were changed in December, so I have a feeling that pulling the packs off the old plugs then reinstalling them over the new ones kinda "shook up" the coils and is making them start to fail.

 

+1 on what @DaveW68 posted above for symptoms. My car refused to throw a code, just a CEL flashing so I would pull over and turn the engine off. When I turned it back on everything was normal again, no stored codes, etc. I finally got it to store a code for misfire and one pointing to the coil (I'm forgetting the exact code at the moment). The car had 100k miles so all new coils and no issues since.

 

Same as Dave for me as well although my car did save the code each time even though the check engine light went away after restarting the car. The code reports as a misfire on a particular cylinder. At highway speeds the shaking from the misfire is pretty aggressive. At idle it’s less aggressive but still very noticeable and uncomfortable. It’s very obvious something is wrong. But I wanted to offer the following as well. Before coil replacement and without the check engine light on, at times I could occasionally (maybe 15% of engine starts) feel what seemed to be a slightly rough idle after starting the engine and after it came down from high idle. It was something I could feel in the seat of my pants that felt like a slight abnormal vibration. I didn’t know what was causing it and it wasn’t super obvious but it was still annoying. After coil replacement, I haven’t felt this since and it’s been a couple months now. In my mind, that occasional slight vibration after engine start was an early indication of a coil going. There’s no way to prove my theory, but that’s what I believe.

 

That is very interesting, my car always has the shakes for 3 - 5 seconds after a cold start, then it smooths out and runs fine. I've asked my indy several times and they say they don't notice anything wrong.

I also get occasional vibration around 1,500 rpm on the highway, particularly under load, e.g. slight uphill (about 60 mph in D8).

Never had any codes but always wondered about these symptoms and if they might be related and possibly involve the coils.

 

How long have you owned the car? and has it always done that?

 

I've had my car since December. Yes, the symptoms mentioned were present when I bought it. I replaced one coil, the plugs and more recently each of the plug boots. These steps got rid of oil that had accumulated in the plug bores and the car runs much better now, except for the shaky starts and occasional light vibration at highway speed. Based on what's been discussed here and the likelihood of coil trouble, I have considered the following next steps:

1) Replace the remaining three coils, close the hood and move on
2) Buy one new coil and try it in different positions to see if that identifies a bad one and clears these symptoms
3) Go to the dealer and pay the diagnostic fee to see if they can detect a coil problem. If they can, that coil (or coils) will be replaced under warranty. If not, I'm out the diag fee and nothing changes

 

I considered your option number one also but ultimately decided not to since Mercedes replaced the confirmed failed pack for me under warranty and that fixed my problem. I would like to have them all replaced, but decided not to spend the money on parts that are under warranty if they fail in the future. Regarding your option, three, if you haven’t had the engine light on and a code stored for a misfire, I’m thinking it’s almost guaranteed that they would not diagnose it as having a problem and offer to replace anything under warranty. But if you have had the engine light on, and there is a misfire stored in memory, then you will be in the situation I was in and for me they replaced not only the coil pack on the misfiring cylinder, but also the spark plug for that cylinder under warranty, and I did not have to pay a diagnostic fee either.