rik881

I have a problem with my ignition coils. My S500 always idled shaky when cold. I also have leaking valve covers. I tightened the bolts for the valve cover a little and thought everything was allright until i left the car for a few days without driving it. I now got misfire cilinder 1 and when i touch the accelerator the car turned off. So i read the forum and found that i have to check the coil pack and cables and spark plugs. So i went ahead and took off the ignition coils, what i thought was sand i now noticed to be oil, everything was covered in oil. So i cleaned the coil from cilinder one and yes it is running now. Not good but it is running. No more misfire just a little humm when revving. When inspecting the coils i noticed that they are all cracked. I remember from my Porsche that cracked coils have to be changed.

I suppose i have to change them all since they are cracked. I have been searching for anyone with this same problem on any type off Benz with cracked coils ,a lot of Benzes use this same ignition coil but to my suprise i can not find anything about this topic.

They are various types off replacement ignition coils, 100$ for 8 unbranded, 150 for red ones which are told to be high performance or the original Bosch ones for about 300$.

How should i continue? Do i need to replace the spark plug wires as well?

lganski

You should replace the coils, wires, and plugs after you put new gaskets on to stop the oil leaks. If the coils are cracked they are open to moisture which on a high voltage circuit is not good. If the coils are showing that kind of damage then the wires will be in the same shape. While you have the plugs exposed change them. The ones that are in there are probably old. As far as what coil to buy I would go with the higher quality because this is a critical part of the engine. Fix the oil leak while you have everything off.

rik881

Why did they crack in the first place? My car has less then 20k miles. That's why i never bothered to change the plugs. I never thought the ignition to go bad so soon. My Cl500 has a lot more miles and the coils are still good.

I will need to replace the coil wiring too, connector has become all brittle and the plastic breaks when disconnecting. Does anyone have a part number for this please?

MikeKerr7

Coil part # BOSCH 00107 , for sale at RockAuto for 52.79.

1287013003
Bosch OEM - Terminal Repair Kit For 2 Prong Bosch Injector Type Plug (7.74 each at auto haus az or 7.45 each at Rock Auto)
Miscellaneous usage as required, please verify plug on existing parts. For repair of female harness plug, for attachment to 2 pin male prong fuel injectors and similar 2 pin Bosch connectors. Kit includes 1 terminal with wire spring clip, 1 boot and 2 wire ends (female).

MikeKerr7

You might also want to look at replacing the entire harness, under $400 for the harness.

Engine Wiring Harness

Connects All Of The Sensors, Senders, Fuel Injectors And Ignition Coils To The ECU

Stock Code 2205409232 Manufacturer Mercedes Benz Categories Engine Assemblies ENGINE CABLE HARNESS S/CL-CLASS

lganski

you only have 20K miles on an 03?

rik881

Not even 20k miles
Nobody experienced cracked coils here? May be because the valve cover was leaking the oil messed with them. All 8 are cracked.
I'l need a lot of money for parts now. Spark plugs and wires, harness and coils and finally a new front shock. Valve covers gaskets are arriving next week. Will do the CL500's covers as well. I might skip on the harness for now.

ibeforreal

Personally, I have never seen a cracked ignition coil. The fact that you say all 8 are cracked just doesn't sound right especially since there is less than 20k miles on the car. How long have you had the car?

rik881

I have seen cracked coils but not on a Benz. Cayennes for example suffer a lot from cracked coils. I have the car for a year now. The car had been parked for years when i bought it.