How to replace the serpentine belt, tensioner and pulleys on a Mercedes - W222 - S550 |

[@techguy1678]

Jose - Brother your videos are extremely helpful. Thanks a bunch for sharing these. I have been working on my own cars for around 10 years now but am new to the M278 engine on a W221; it helps to watch what you're doing and be able to replicate that on my vehicle.

[@josecitomarin]

Thank you so much for your comment. I’m glad my videos are helping. Stay tune for more

[@cd8431]

Congrats to your wife and you for working on this together. What a team work!!!. Your videos have helped a lot of Benz owners. You can get your wife a Benz now, she knows how to fix car just like you. Do you have p/n for the pulley #7 and the tensioner #9. Thanks again Jose for a great video.

[@josecitomarin]

Hi. Thank you so much. The parts are listed with the links on the description you can just click on them

[@paulbernal7433]

I am definitely doing the solenoids, the sensors, the belt and the pulleys at the same time

[@josecitomarin]

Oh yes. Do it all together!

[@ericardila7783]

Jose, excellent videos, I've been working on my 2016 following your advice. what is the service manual you are using? I would like to buy it. Thanks!

[@josecitomarin]

Hi, I use alldata. Use the following link to get discounts if you are in the USA. www.pjatr.com/t/3-268932-324229-140959

[@00Broy]

Your videos are great. Super detailed. Thank you. I see you have put sacrificial pigtails on your cam position sensors. Where did you get these to fit the 3 pin connectors? The genuine Mercedes ones are 2 pin connectors and only fit the cam solenoids (but not the position sensors) on my M278 engine.

[@josecitomarin]

Thank you so much. I did not put it on the position sensors yet. But I am going to do a video on it soon. A subscriber told me where to get them

[@scotthiddleston8246]

Can you replace just the pulley on the tensioner assembly, or do you need to replace the whole tensioner assembly? Mine has a noisy bearing.

[@josecitomarin]

I wouldn’t do just the bearing. You are going to do all that work just for a pulley. Change the entire thing. How many miles would you say are in that tensioner? If it’s original, definitely change it all

[@scotthiddleston8246]

@@josecitomarin 32K miles on it. After further examination it seems to be the AC compressor pulley making the noise.

[@orgundeveci1613]

Great video, very informative as always. May I ask, at what mileage you changed the pulleys and tensioner? What was the reason? Did you hear a noise or just preventative maintenance? thanks a lot.

[@josecitomarin]

Thank you so much for your comment. I changed them at 50k mikes. It was time for the belt to be replaced so I decided to replace everything since I was going to be there anyway. I also had to remove the duct pipes for the adjuster magnets. So I decided to do everything at once so I don’t have to take it all apart again and made two separate videos out of it. Nothing was making any noise.

[@orgundeveci1613]

@@josecitomarin Thank you for your respond. Appreciated. I thought 50k miles is also too early to change the belt for Mercedes. But you were already there for the camshaft magnets. Make sense.

[@josecitomarin]

@@orgundeveci1613 right, you are already half way there. May as well

[@claytoncox66]

Do you know the torque spec for the top guide pulley? I am replacing all of them.

[@josecitomarin]

Thank you so much for your comment. 70 Nm or 52ft lbs

[@claytoncox66]

@@josecitomarin thank you!

[@josecitomarin]

@@claytoncox66 you are welcome

[@claytoncox66]

@@josecitomarin when I was looking at the work instruction, one of pulleys is listed at 35NM. Which one is this?

[@josecitomarin]

@@claytoncox66 yes. They say in the directions to torque the pulley to the coolant pump and oil filter. But I torqued them to 20 and gave them a little extra pressure. I also asked somebody that works at the dealer and he thinks the same way. They are working perfectly

[@Rmayrap]

My man came through with the video! About to tackle this job this weekend myself. You didn't change the big top Drive Belt Idler Pulley 6112340193? Also I noticed you didn't use part 2782020219? Did you just order two of the 2782020519 instead? Just trying to figure out all the correct parts I need.

[@josecitomarin]

No problem my friend. I did not change the top pulley. FCP says it’s not necessary. I should have done it. But in any case it will be simple to do it at a later time since I just have to loose tension on the belt and take it off. I have another interesting video coming as well.

[@Rmayrap]

So did you get 2782020219 or did you use two of the 2782020519 pulleys?

[@josecitomarin]

@@Rmayrap they are different get the 2 of them

[@Rmayrap]

You link says to get two of the 2782020519 that's why I was asking.

[@josecitomarin]

@@Rmayrap I have to change that. Thank you

[@CorteviosAllen-xm1bj]

Hose my belt keeps slipping off of my oil filter housing pulley

[@josecitomarin]

Hi. Thank you so much for your comment. Did you do anything to the engine? How long ago did you replace the belt, pulleys and tensioner? Did you ever change them? One of the pulleys may be misaligned, the belt may be bad and it comes out always by the oil pulley because that pulley is bad. Check if any of the pulleys have play. Also check if the pulleys are turning easily. By now that belt is probably bad as well because it keeps getting hit at the edges when it comes out.

[@CorteviosAllen-xm1bj]

@@josecitomarin need to change my upper pulley bracket. I took them all apart again and that one is stripped. Thanks Jose.

[@josecitomarin]

@@CorteviosAllen-xm1bj okay great. I’m glad you found the issue