SL/R230: Serpentine belt, pulley replacement
Thread Starter
Member
Joined: Sep 2013
Posts: 157
Likes: 33
From: Walpole, MA USA
2004 SL500
Serpentine belt, pulley replacement
I'm hearing an oscillating noise from the front of the engine that I suspect is a pulley reaching end of life, so I'm going to take the opportunity to swap out my serpentine belt using the kit that I've just purchased from FCPEuro.
https://www.fcpeuro.com/products/clo...it-e320beltkit
I've watched several videos to prep. Here are a couple:
https://www.youcanic.com/vehicle/mer...placement-3083
I currently have on hand:
https://www.fcpeuro.com/products/clo...it-e320beltkit
I've watched several videos to prep. Here are a couple:
I currently have on hand:
- a 17mm socket (both short and deep)
- multiple sizes of socket extensions
- multiple sizes of torque wrenches (for installation).
- a female torx socket set
- blue loctite
- magnetic work light
Thread Starter
Member
Joined: Sep 2013
Posts: 157
Likes: 33
From: Walpole, MA USA
2004 SL500
Started and finished the serpentine belt replacement this morning. Somewhat frustratingly, the existing belt appears to be OEM and original, but in great shape at 16 years and 62k miles; obviously I replaced it anyway. The upper pulley and the tensioner both exhibited some bearing noise, but nothing terrible. In my opinion, this wasn't a job that HAD to get done, but it's done and so one less thing to think about.
Video link, job complete
- I started the morning by hanging a work light from my hood latches and it was perfectly situation just above the area between the engine block and the fan shroud.
- Next up, gathered the tools, parts, and drew a diagram of the belt layout.
- I released the pressure on the belt and stuck a hex key into the pinhole to hold the tensioner pulley in place.
- removed the belt. The most difficult part of the removal was getting out from around the power steering pump.
- Removed and replaced the upper pulley. At this point I realized that I should probably remove the air inlets and front upper engine cover.
- Removed and replaced the tensioner pulley. I used the old Germanic method of torquing it down, set it to Gutundfickentite.
- I placed my diagram on the engine and went to work snaking the belt back in place.
- I started at the power steering pump, worked my way down, then went bottom up.
- I ended at the upper pulley.
- Made sure the grooves were all in the right place
- Removed the pin from the tensioner (promptly dropped it and had to spend a couple of minutes tracking it down.
- I set my phone camera to video, placed it to watch the startup (in case the belt jumped I wanted to know from where)
- Started the car, let it run, no warnings, no belt jumping, job done.
Video link, job complete
Last edited by sean65; Apr 21, 2020 at 06:16 PM. Reason: Added video link
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From: Orbiting the planet
This place is a joke.
Clamp the bottom of the assembly in a bench vise.
For future reference, you don't need to install this pin/holder if you are replacing the tensioner. It's purpose is for installation of the belt only. Simply relieve the tension, holding your tool with one hand in the released position, and slide the belt off, then slowly reapply tension until it comes to it's built in stop point. Then you won't have this dilemma. 👍🏻
On another note you'll never need a belt routing diagram for a Mercedes. Every MB engine built with a serpentine belt follows the same pattern- the belt always goes over the top of the crank pulley then under the belt tensioner that's on the right, wrapping back over the top of tensioner. Then simply follow the belt along, smooth pulleys get the smooth belt side and grooved pulleys get the grooved belt side. It's foolproof, in a German sort of way!
For future reference, you don't need to install this pin/holder if you are replacing the tensioner. It's purpose is for installation of the belt only. Simply relieve the tension, holding your tool with one hand in the released position, and slide the belt off, then slowly reapply tension until it comes to it's built in stop point. Then you won't have this dilemma. 👍🏻
On another note you'll never need a belt routing diagram for a Mercedes. Every MB engine built with a serpentine belt follows the same pattern- the belt always goes over the top of the crank pulley then under the belt tensioner that's on the right, wrapping back over the top of tensioner. Then simply follow the belt along, smooth pulleys get the smooth belt side and grooved pulleys get the grooved belt side. It's foolproof, in a German sort of way!
Last edited by E55Greasemonkey; Apr 26, 2020 at 01:18 PM.
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From: Gretna, NE
'03 SL55 Black, '03 SL500's Aegean, Mars Red, Tazanite, Alabaster, '11 S550 Flint Gray
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From: Rogersville, Alabama
2006 SL55
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SL55AMG, GL450, SLK, S550, Maserati Coupe
I love how Continental, the tire company, has kits available for a lot of Mercedes models that will consist of tensioner, idler pulleys and belt, a complete kit, all very high quality, and you don't have to chase part numbers and shop all over for various items. Thanks, Continental!
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95 SL600
MBWorld Fanatic!
Joined: Aug 2020
Posts: 1,326
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From: Gretna, NE
'03 SL55 Black, '03 SL500's Aegean, Mars Red, Tazanite, Alabaster, '11 S550 Flint Gray
A few years back, there was a push to at least have similar look, naming conventions, and packaging worldwide. As a result, the cogged belt was discontinued. The current belt also has a very quiet compound, just not the cogs.
