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After sitting for roughly a week, and charging / conditioning battery with CTEK charger, started vehicle, check engine light on, smell of gas, rough idle.
Drove for about 10 miles, engine performed slightly rough.
Came home, cleared code, haven't started since. Plan to swap coils and drive again to see if the same code returns.
Spark plugs changed (dealership) at 60k and now at 80k.
Looking for advice.
Prior to coil swap:
Would I need MB spark plug grease (A 002 989 80 51 - spark plug grease .pdf attached) before the swap or has anyone just used dielectric grease instead?
If new coil is needed:
Is BOSCH 0986221058 the proper coil? Would you guys replace all at once?
Also - a lot of the threads mention a switch to NGK over Bosch for spark plugs.
Mercedes STAR bulletin says NGK spark plugs are a no go per attached spark plug indexing .pdf
Has anyone had negative results using NGK spark plugs which are said to perform better?
Finally MB is stating I need to use their spark plug tool at $73 bucks on Amazon. Is there something special about it or can I simply use any spark plug socket like this:
Dielectric grease is fine. Many here use NGK with no issues, in fact they appear as oem installation sometimes and to my knowledge they index correctly.
I've never has to use sonething other than a regular plug socket. Be sure you first twist the coil/boot gently to help break it loose from the plug, then try to grip the boot and not the coil as you remove it. For me, I'd only replace the specific coil.
I have the same car and it had the same issue in December. I was getting multiple misfires (cyl 5,3 and1) with rough running. Swapped the coils around and the misfires moved around but not in the pattern I was expecting.
I decided to replace all of them anyway ( the car had 114k miles) and the misfires went away. I used Delphi coils from FCP Euro , I think they are the OE ones.
This smoothed up the engine and helped with eliminating the slight vibration I was experiencing when going uphill when on cruise control.
I replaced the spark plugs awhile ago and used the Bosch recommended ones (link here). BTW, your engine should be M273, no direct injection on these.
As for the grease, I used a 3M silicone paste with dielectric properties (
).
I used a regular deep socket for the plugs, if I remember correctly it was a 16mm. Use a magnet or the end of a hose to fish out the plugs once you get them loose.
I doubt my coils were ever replaced so I'll start there. Seems a bit early for them to go if yours made it to 114k but who knows. Did you guys index the NGK spark plugs? Is so, did you have to use shims?
Began the task of switching coils and one of the the coil sockets broke in the coupling. The other came off no problem. Pushed the tab back the exact same way on both.
Thankfully the coupling is available online for about $3 so I'm going to replace them all just in case.
I heard about stabilant 22A being used on these contacts but the cost is $$$$.
Not sure I should use dielectric grease or simply leave it be.
Interestingly all my coils are Delphi and marked with the MB logo, although Bosch seems to be recommended in the places I've researched.
Unsure if this would happen with Bosch or if its normal (especially since the couplings are readily available).
Looks as if the coupling separates at the socket so hopefully these wont be a PIA to repair / replace...just glad I these parts are available and cheap.
Also -
Here is a pic of the BOSCH spark plugs after 20k miles...would you guys replace based on their appearance? Looks as if some green stuff (lube of some kind) was used...on the coils too. Not sure what it is. Gunky though.
Began the task of switching coils and one of the the coil sockets broke in the coupling. The other came off no problem. Pushed the tab back the exact same way on both.
Thankfully the coupling is available online for about $3 so I'm going to replace them all just in case.
I heard about stabilant 22A being used on these contacts but the cost is $$$$.
Not sure I should use dielectric grease or simply leave it be.
Interestingly all my coils are Delphi and marked with the MB logo, although Bosch seems to be recommended in the places I've researched.
Unsure if this would happen with Bosch or if its normal (especially since the couplings are readily available).
Looks as if the coupling separates at the socket so hopefully these wont be a PIA to repair / replace...just glad I these parts are available and cheap.
Also -
Here is a pic of the BOSCH spark plugs after 20k miles...would you guys replace based on their appearance? Looks as if some green stuff (lube of some kind) was used...on the coils too. Not sure what it is. Gunky though.
Forgot to mention that the coils (Delphi) come pre-greased.
Spark plugs look ok.
I wouldn't bother trying to fix that coil, it's safer to just replace all of them.
I bought my car when it had 88k miles and the roughness of the engine under slight load has been there since the first time I drove it so I'm thinking the coils were on their way out ever since.
In most cases they need replacing after 100k miles.
I think Northern Virginia traffic and too many short trips did me in.
Might have made it to 100K otherwise.
Hopefully the coils are the issue and not something else.
I heard replacing spark plugs at he same time as replacing the coils is recommended but I agree they dont look bad at all.
Based on what I've been reading the NGK's are superior to the BOSCH plugs as far as fuel / performance.
No idea if the Delphi coils are "better" than the BOSCH coils but the Delphi's are definitely cheaper ($24 vs $37 on Rock Auto), plus Delphi was already on the car anyway (with the MB logo) per the pics.
I think Northern Virginia traffic and too many short trips did me in.
Might have made it to 100K otherwise.
Hopefully the coils are the issue and not something else.
I heard replacing spark plugs at he same time as replacing the coils is recommended but I agree they dont look bad at all.
Based on what I've been reading the NGK's are superior to the BOSCH plugs as far as fuel / performance.
No idea if the Delphi coils are "better" than the BOSCH coils but the Delphi's are definitely cheaper ($24 vs $37 on Rock Auto), plus Delphi was already on the car anyway (with the MB logo) per the pics.
Also -
Delphi warranty = 36 months
BOSCH warranty = 12 months
Going with Delphi...
That's a good choice, mine have been perfect so far. I'd recommend going with FCP just for their lifetime warranty. You'll pay 6$ more per coil but you have the safety net that warranty offers.
As far as performance goes I would say we, as regular users, are not going to notice any difference between Bosch or Delphi.
That's a good choice, mine have been perfect so far. I'd recommend going with FCP just for their lifetime warranty. You'll pay 6$ more per coil but you have the safety net that warranty offers.
As far as performance goes I would say we, as regular users, are not going to notice any difference between Bosch or Delphi.
Saw your message after I pulled the trigger on the cheapest price with Rock Auto. Next time I'll know better. Lifetime warranty definitely worth $6 for sure. Hopefully I won't need it! I'll be checkin with FCP first from now on. Thanks!
If the plug threads have any lubricant on they they won't torque to the proper index point. That looks more like oil contamination from somewhere. I just replaced mine recently and they were perfectly clean, I doubt they were replaced before, but I bought the car at 65k miles, and seems from the CarFax the maintenance was only done at the dealer. They really didn't look dirty or worn at all, could have been replaced, but my local dealer would not pull the previous service info for me. I know they are able to pull this from other dealers nation-wide.
If the plug threads have any lubricant on they they won't torque to the proper index point. That looks more like oil contamination from somewhere. I just replaced mine recently and they were perfectly clean, I doubt they were replaced before, but I bought the car at 65k miles, and seems from the CarFax the maintenance was only done at the dealer. They really didn't look dirty or worn at all, could have been replaced, but my local dealer would not pull the previous service info for me. I know they are able to pull this from other dealers nation-wide.
Nah, can't be oil. The porcelain is still white as new. Perhaps some lube on the threads but I dont think its oil as oil would have to pass the spark to get to the threads right? Tip dry and clean. Spark plug well dry as a bone. I thought oil would look like this...
03-17-2019, 02:54 PM
