Spark plug exploded. Need help!!!
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Junior Member
Joined: Sep 2008
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2006 c280
Spark plug exploded. Need help!!!
Hi guys,
Changed out my spark plugs the other day. Used a torque wrench set to 20nm, no diaelectic grease, and the OEM bosch plugs were pre-gapped, but I double checked them anyway.
Anyway, after changing them, I cranked the car, got no CEL or skipping or anything, and gently revved the engine to 2500 rpms. No problems. Turned the car off and went to bed.
Yesterday, I crank the car and drive a mile down the road to the nearest highway. As soon as I hit the acceleration ramp, I go WOT. a second later, I hear a sound like a shotgun, followed by a repeated knocking noise, and a squeeking noise that sounds like a belt slipping. CEL begins flashing and the car has almost no power (I'm guessing it is in limp mode). CEL is now solid and car stalls at idle. I barely made it the mile back home.
I open the hood and begin removing coilpacks. Turns out the middle spark plug on the driver's side bank has exploded. Maybe I cracked it when installing, but like I said, I used a torque wrench. Anyway, the plug threads are stuck in the cylinder and I recovered most of the plug internals and ceramic coating but I've got no idea if anything fell into the cylinder.
What the hell do I do now? It's 60 (interstate) miles to the nearest dealership. Is it safe to drive? Should I even start it? I'm afraid to even drive to autozone to have codes read.
Thanks
Changed out my spark plugs the other day. Used a torque wrench set to 20nm, no diaelectic grease, and the OEM bosch plugs were pre-gapped, but I double checked them anyway.
Anyway, after changing them, I cranked the car, got no CEL or skipping or anything, and gently revved the engine to 2500 rpms. No problems. Turned the car off and went to bed.
Yesterday, I crank the car and drive a mile down the road to the nearest highway. As soon as I hit the acceleration ramp, I go WOT. a second later, I hear a sound like a shotgun, followed by a repeated knocking noise, and a squeeking noise that sounds like a belt slipping. CEL begins flashing and the car has almost no power (I'm guessing it is in limp mode). CEL is now solid and car stalls at idle. I barely made it the mile back home.
I open the hood and begin removing coilpacks. Turns out the middle spark plug on the driver's side bank has exploded. Maybe I cracked it when installing, but like I said, I used a torque wrench. Anyway, the plug threads are stuck in the cylinder and I recovered most of the plug internals and ceramic coating but I've got no idea if anything fell into the cylinder.
What the hell do I do now? It's 60 (interstate) miles to the nearest dealership. Is it safe to drive? Should I even start it? I'm afraid to even drive to autozone to have codes read.
Thanks
MBWorld Fanatic!
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From: fort worth, tx
06 C230 SS 6spd
I wouldn't drive it if I was you. I would get it towed to a good Indie shop and have them check it out. You can borrow an OBII reader from autozone and read the codes and return it when your done.
Thread Starter
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2006 c280
It's being towed now.
Unfortunately, there's no good indie shop close to me either. I ordinarily use Jonathan Hodgman at Blue Ridge Mercedes in Atlanta. He's excellent, but nearly 120 miles away. That's one hell of a towing bill.
All the same, I'm pretty sure it's my fault. I think I overtightened the plugs, even though I used a torque wrench.
Unfortunately, there's no good indie shop close to me either. I ordinarily use Jonathan Hodgman at Blue Ridge Mercedes in Atlanta. He's excellent, but nearly 120 miles away. That's one hell of a towing bill.
All the same, I'm pretty sure it's my fault. I think I overtightened the plugs, even though I used a torque wrench.
MBWorld Fanatic!
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From: Huntington Beach, Ca.
'17 Jaguar XF
That shouldn't cause plugs to "explode". Maybe you cross threaded them and the torque you were reading may have been accurate but the plugs weren't really seated. Can you be more specific what "explode" means? What was the plug number/type you installed?
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2006 c280
This is what I mean by "exploded"...
The NKG plug on the top was what was in the car prior to the replacement. The two on the bottom are the result of my recent problem. Turns out that all 6 plugs were damaged. Only two of them were so badly "exploded" that it was visibly apparent. The other 4 looked good when seated in the cylinder but upon removal it turned out that the ceramic and internals had separated from the threads and the electrode. We were able to actually remove 1 of those 4 plugs whole, but it was still damaged. The ceramic spun freely from the threads.
The rubber boot on one of the coil packs was actually blown apart, like elmer fudd's shotgun when Bugs Bunny sticks his finger in the barrel.
The plugs are Bosch Platin (platinum) number YR7MPP33. They were the ones recommended when I put the make model and year of my car into Autohausaz. They claim they are OES (not OEM). As a matter of fact, they are the only plugs available on Autohausaz for an '06 c280 272.940
I'm definitely no master mechanic, but I'm not an idiot either. I'm pretty sure I know how to work a torque wrench (90 degree force, no cheater bar, no grease, only leverage from the handle). I'd feel a lot better if I didn't do this. But I'm not convinced yet.
The NKG plug on the top was what was in the car prior to the replacement. The two on the bottom are the result of my recent problem. Turns out that all 6 plugs were damaged. Only two of them were so badly "exploded" that it was visibly apparent. The other 4 looked good when seated in the cylinder but upon removal it turned out that the ceramic and internals had separated from the threads and the electrode. We were able to actually remove 1 of those 4 plugs whole, but it was still damaged. The ceramic spun freely from the threads.
The rubber boot on one of the coil packs was actually blown apart, like elmer fudd's shotgun when Bugs Bunny sticks his finger in the barrel.
The plugs are Bosch Platin (platinum) number YR7MPP33. They were the ones recommended when I put the make model and year of my car into Autohausaz. They claim they are OES (not OEM). As a matter of fact, they are the only plugs available on Autohausaz for an '06 c280 272.940
I'm definitely no master mechanic, but I'm not an idiot either. I'm pretty sure I know how to work a torque wrench (90 degree force, no cheater bar, no grease, only leverage from the handle). I'd feel a lot better if I didn't do this. But I'm not convinced yet.
Last edited by kastnna; Aug 29, 2010 at 04:13 PM. Reason: apparently I don't know how to upload images
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From: Orlando, FL
C240
I'm sort of leading towards mleskovar's explanation. You used the torque wrench for every plug, and let me tell you, I had the worst time fitting even my regular wrench (which is smaller) into the engine bay, near the rear of the engine, to change out my plugs in my c240. I found it very easy to cross-thread.
Let us know how it goes, good luck!
P.S., I just saw the picture. Looks nasty.
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Thread Starter
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2006 c280
I COULD have cross threaded, but I'm not sure.
Each plug was installed using a spark plug socket and a 6" ratchet extension. No ratchet was used at first. I installed them all by hand by simply spinning the ratchet extension between my fingers. They all went in effortlessly. I only involved the torque wrench after hand tightening.
And, as I said, I managed to remove one plug completely although it was damaged. There didn't seem to be any sign of cross-threading on the threads. Doesn't seem likely that it would be the only one not cross-threaded and yet it still suffered damage.
We'll see.
Each plug was installed using a spark plug socket and a 6" ratchet extension. No ratchet was used at first. I installed them all by hand by simply spinning the ratchet extension between my fingers. They all went in effortlessly. I only involved the torque wrench after hand tightening.
And, as I said, I managed to remove one plug completely although it was damaged. There didn't seem to be any sign of cross-threading on the threads. Doesn't seem likely that it would be the only one not cross-threaded and yet it still suffered damage.
We'll see.
MBworld Guru
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From: Diamond Bar, CA
W206 PHEV AMG
and yes, you might have debris inside the cylinder.
those are #2 and #5 cylinder btw.
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2006 c280
I'm trying to remain calm and not jump to conclusions, but it's hard to sit around and wonder if I'm responsible for massively damaging my engine.
If it turns out that autohaus sold me the wrong plugs, I'm going to enter a world of pissed-off that the likes of which have never been seen. These were the ONLY plugs recommended for my make and model of car.
I'll just have to wait and see.
If it turns out that autohaus sold me the wrong plugs, I'm going to enter a world of pissed-off that the likes of which have never been seen. These were the ONLY plugs recommended for my make and model of car.
I'll just have to wait and see.
Out Of Control!!
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From: OC
a quarter mile at a time
It's ALWAYS ALWAYS a good idea to check and recheck parts, and finally, compare what you pull to what you're putting in. I know it's not going to make you feel any better, but there are so many rolling changes in these cars it's always hard to keep track.
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2019 G70 6MT & 2022 Ford Maverick XL
Autohausaz doesn't always recommend the right things and not just about spark plugs and that's why I no longer use them. It's best to use RMEuropean or getmercedesparts.com.
I can imagine that this is going to be quite expensive to fix. Sorry man.
I can imagine that this is going to be quite expensive to fix. Sorry man.
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From: Llandudno, Cape Town, South Africa
late 2009 CLK 350 Coupe Elegance, '65 Jaguar S Type wires
Super Moderator
Joined: Jun 2008
Posts: 19,942
Likes: 192
From: Llandudno, Cape Town, South Africa
late 2009 CLK 350 Coupe Elegance, '65 Jaguar S Type wires
I'm trying to remain calm and not jump to conclusions, but it's hard to sit around and wonder if I'm responsible for massively damaging my engine.
If it turns out that autohaus sold me the wrong plugs, I'm going to enter a world of pissed-off that the likes of which have never been seen. These were the ONLY plugs recommended for my make and model of car.
I'll just have to wait and see.
If it turns out that autohaus sold me the wrong plugs, I'm going to enter a world of pissed-off that the likes of which have never been seen. These were the ONLY plugs recommended for my make and model of car.
I'll just have to wait and see.
Super Moderator
Joined: Jun 2008
Posts: 19,942
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From: Llandudno, Cape Town, South Africa
late 2009 CLK 350 Coupe Elegance, '65 Jaguar S Type wires
There is something screwy going on here - the YR-7-MPP-33 has a 26.5mm reach & is the correct OE plug for the 2006 C280 M272.940-203.054
The plug on the left in the pic above clearly is of shorter reach (NGK?)
Where are the compression washers from the 2 new plugs? Even so they are longer.
I wonder if the shorter plug had suffered flame shielding & built up a hard carbon slug in the plug threads & when the correct length plug was fitted it shoved this into the combustion chamber & caused mayhem. This would seem unlikely??? I'm confused unless they were hopelessly overtightened.
I wish you well with this problem - something does not add up. The plugs you took out seem wrong & the new ones correct.
The plug on the left in the pic above clearly is of shorter reach (NGK?)
Where are the compression washers from the 2 new plugs? Even so they are longer.
I wonder if the shorter plug had suffered flame shielding & built up a hard carbon slug in the plug threads & when the correct length plug was fitted it shoved this into the combustion chamber & caused mayhem. This would seem unlikely??? I'm confused unless they were hopelessly overtightened.
I wish you well with this problem - something does not add up. The plugs you took out seem wrong & the new ones correct.
Last edited by Glyn M Ruck; Aug 29, 2010 at 09:15 PM.
Out Of Control!!
Joined: Nov 2005
Posts: 18,677
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From: OC
a quarter mile at a time
There is something screwy going on here - the YR-7-MPP-33 has a 26.5mm reach & is the correct OE plug for the 2006 C280 M272.940-203.054
The plug on the left in the pic above clearly is of shorter reach (NGK?)
Where are the compression washers from the 2 new plugs? Even so they are longer.
I wonder if the shorter plug had suffered flame shielding & built up a hard carbon slug in the plug threads & when the correct length plug was fitted it shoved this into the combustion chamber & caused mayhem. This would seem unlikely??? I'm confused unless they were hopelessly overtightened.
I wish you well with this problem - something does not add up. The plugs you took out seem wrong & the new ones correct.
The plug on the left in the pic above clearly is of shorter reach (NGK?)
Where are the compression washers from the 2 new plugs? Even so they are longer.
I wonder if the shorter plug had suffered flame shielding & built up a hard carbon slug in the plug threads & when the correct length plug was fitted it shoved this into the combustion chamber & caused mayhem. This would seem unlikely??? I'm confused unless they were hopelessly overtightened.
I wish you well with this problem - something does not add up. The plugs you took out seem wrong & the new ones correct.
Super Moderator
Joined: Jun 2008
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From: Llandudno, Cape Town, South Africa
late 2009 CLK 350 Coupe Elegance, '65 Jaguar S Type wires
Yeah - e - something is wrong here. My car came with & I still run Bosch. But the 112 is of course twin plug per cylinder.
If the OP had bought plugs for this car from RMeuropean they would have given him YR-7-MPP-33 Bosch Plat. It's all they carry for that engine & in ROW it is the OE plug. We never see NGK plugs on Benz cars.
If the OP had bought plugs for this car from RMeuropean they would have given him YR-7-MPP-33 Bosch Plat. It's all they carry for that engine & in ROW it is the OE plug. We never see NGK plugs on Benz cars.
Last edited by Glyn M Ruck; Aug 29, 2010 at 09:52 PM.
