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Hi guys, I'm about to change the spark plug on my 13 cls63 wth 50k miles on it. I found a couple different part numbers Q-4-15-0038 for around $18, and 004-159-81-03 fis about double the price. I'm not sure about the fitment of the Q-4-15-0038. Has anyone experienced with this? Thank you all.
I bought a set of genuine MB spark plugs and they had laser engraved NGK numbers on them, but I'm not sure they are same as NGK branded plugs that are listed as compatible. MB insists direct injected engines require their spark plugs to be indexed. The MB plugs I bought were all identically threaded such that when seated, the ground electrodes are in a prescribed orientation. FCPEuro can probably tell you if the Bosch and MB plugs are one in the same or if there is a difference. For me, a $2 difference between MB and NGK wasn't worth thinking about. With your MB plugs being 3x the Bosch plugs, I'd spend a few minutes on the phone.
So I made the call to FCP as your suggestion. I'm going to order the Bosch. The coil is even more crazy expensive. Bosch: $57. MB $91. Do you recommend to replace those as well?
Read some comments about the problem with indexing and gap so I decided to go with Genuine MB plugs. The coils are the one I have more concerns because they are so expensive.
So I made the call to FCP as your suggestion. I'm going to order the Bosch. The coil is even more crazy expensive. Bosch: $57. MB $91. Do you recommend to replace those as well?
Unless you're receiving misfire codes, or unless there's physical damage, I'd stick with the originals.
What tool is used to remore the plug wire connector? I broke the clip on the top the plug. I broke 3 of them. I'm afraid that with vibration, it wont keep the connector in place.
There's usually not a special tool necessary, but there are a variety of locking mechanism designs. Usually, there's a place that needs to be compressed to release a locking tab. Other times, the locking tab requires a piece to slide, and sometimes both.
I finally figure it out. Its too late, i broke 3 of them. It seems to hold the wire connection ỉn place but not very tight. Will replace if there is a problem. Thank you.
OMG, after inserting the spak plug, the socket got stuck inside. Tried to insert the extension but it wont snap back on because cannot see it. Tried to take picture, see it there but unable the snap the extension back on. whatever a disaster!
So i used this socket & entension. I managed to insert ỉn but it wouldnt snap on the plug. And now its stuck, i cant take it out. Can i spray by the connected join to lubricate? I am trying to seperate the 2 pieces and take out one by one.
Got it done, finally. Its the tough job. I warmed the engineb up a lttle bit so there was no problem to pull out the coils. I see oil on the old plugs, do i need to worry about this?
Got it done, finally. Its the tough job. I warmed the engineb up a lttle bit so there was no problem to pull out the coils. I see oil on the old plugs, do i need to worry about this?
boroscope the cylinder, figure out if oil is from intake, or stuck rings….imo, a proline engine flush at each oil change will help start to clean it up. Do you have any smoke on start up or under light or heavy acceleration?
Add a pic of the plugs for us to see.
Last edited by Baltistyle; Mar 20, 2026 at 03:35 AM.
Theres plenty of room is you use the proper extensions and swivel sockets….
don't remember which combination of sockets and extensions I used for this job. none of these are big money when compared to a visit to the MB service center.
boroscope the cylinder, figure out if oil is from intake, or stuck rings….imo, a proline engine flush at each oil change will help start to clean it up. Do you have any smoke on start up or under light or heavy acceleration?
Add a pic of the plugs for us to see.
I just checked the plugs again, only one is a litlle wet. I just don't remember what cylinder. Too much work to remove every single one to boroscope. I don't see any leak from valve cover. Will do the liquid moly pro-line engine flush now. Thank you for your help.
little smoke when startup but its been like that since the đây i bought the car.
I just checked the plugs again, only one is a litlle wet. I just don't remember what cylinder. Too much work to remove every single one to boroscope. I don't see any leak from valve cover. Will do the liquid moly pro-line engine flush now. Thank you for your help.
little smoke when startup but its been like that since the đây i bought the car.
just use it according to the directions. I’ve used it for my past couple oil changes/flushes and still get some debris. I had two wet cylinders. There should be zero smoke on start up and zero smoke under your first heavy acceleration of the day. Smoke on first start up often points to a valve seal. Smoke with first wide open throttle often points to blow by. .
generally, the cylinders to worry about are the ones closest to the turbos. However, that was not where my stuck rings were.
this is after 5k miles since I inspected and saw my two wet cylinders. I did an engine flush at that point, had my valves cleaned, changed my oil twice and then flushed again a week and a half ago. Looking in my oil cap has always been spotless. The assumption is that this debris is coming from perhaps the valve train, or more realistically the rings being slowly cleaned. If you read my story, I always do 3000 mile oil changes, but I was using lots of Ceratec and I think that contributed to my problem. I’ve not used ceratec since. This is the most debris I’ve ever seen in my filter.
Last edited by Baltistyle; Mar 20, 2026 at 06:17 PM.
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