Hi fellow MB'ers,

Hope you can help me with my problem. I have a 2003 c230 K coupe (w203) with a 1.8L supercharged 4 cylinder engine. Yesterday my serpentine belt broke and after closer inspection i noticed the tension pulley was loose in it's engine block socket, I then wiggled it out only to find that the mounting bolt snapped that holds it in place from behind. Its a weird design, there are no bolts holding it from the outer housing, only a bolt that is screwed in from behind. My question is, how do you put a new mounting bolt on from the back of this thing? Does the disk inside the socket come out somehow? Please help. Thanks

I'm not sure what you're talking about, nor asking.
Don't you have a cell phone or a camera?


https://mbworld.org/forums/c-class-w...placement.html


https://mbworld.org/forums/c-class-w...er-pulley.html


https://www.google.com/search?q=M271+tensioner


Mercedes Benz C230 (M271) Tensioner Pulley Replacement



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Thanks for the links RedGrey...in the video you posted he explains exactly what I mean. I now know thanks to you.

At 18 sec's - 40's he states that if you need to replace the whole tensioner, NOT just the pulley, the bolt is only accessible through the back and in order to do that you need to remove the intake manifold and supercharger to get to the bolt through the timing case, crap I was hoping it was a small job, but now I see its a big job. Darn.

Thanks again!

Yup...big job. You'll have to remove the airbox, intake manifold and supercharger, along with associated hoses and connectors. All to reach one bolt.
Have fun!

As a follow up, to those who own a c230 k with a M271 engine. Maybe a good idea to change your serpentine belt and the 2 pulleys as preventative maintenance and piece of mind. I think my pulley seized up from a worn out bearing which put strain on the tensioner and then snapped the bolt, leaving me stranded, and with a hell of a job ahead of me, good thing it was not on the highway. I lost all power options including my power steering.

Note: if you do it yourself, make sure you put the right torque when you tighten the bolts...I'm researching the correct torque and will do a follow up when I find out...

Hey Jamie, Funny that you posted that question because I have the same problem but I already removed the intake manifold and everything above and the only thing left is the supercharger at this point but after removing the 2 bolts on the front by the supercharger pulley I don't know what else its holding it in place specially since everything above its gone.

are you ready for some heavy cursing? you'll have to get under the car and remove the intake muffler (part inside the red square) attached to the supercharger. there are two torx E10 bolts. one is screwed into the supercharger the other into the oil filter housing. after removing the muffler you will have access to the 3rd bold holding the supercharger in place. this bolt you can remove from the engine compartment. if you're a contortionist it's easier. be careful when you pull the supercharger up there is a connector for the air flap underneath.
when you're done:
the 3 bolts holding the supercharger 20Nm
intake muffler bolt to oil filter housing 11 Nm
intake muffler bolt to supercharger 9 Nm

oh and since you will remove the supercharger you better replace the 3 breather hoses and the one-way valve

belt tensioner 58Nm
tensioner pulley 25 Nm
guide pulley 20Nm

OMG! I guess it's time to take a few days vacations because I'm about to rip my hair off ! That sounds bad! I appreciate the detail response and I'm in some sort of panic mode at this point after your explanation. :/
Thanks for the torque specs.

OMG, I have not unpeeled everything that far yet..From what Playfair is saying this stupid tensioner is a royal pain in the ***... This car has been nothing but problem after problem, from premature rusting, to the electrics, to the transmission, to the tensioner, nothing but an over priced, over engineered nightmare of gimmicks...

Playfair, thank you for the update on this thread...