I've spilled P/S fluid all over the belt one day (stupid, I know...) - since then I've had the nasty belt squeek around 3000 rpms. I've tried cleaning it with brake cleaner, SimpleGreen, and various other agents to no avail. I've applied belt dressing to help it along - still no luck.

Now the squeek is getting worse - it's happening more often - nearly everytime I try to accelerate in traffic and is driving me bannanas - I think it's time to replace it.

Could use some help figuring out the best steps to do this. I hope this can be done without removing the fan... I've read that that's not fun.

Can someone plz point me to the right place to look for the how-to (I couldn't find anything in the "How-To" section).

Thx,
James

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1987 Mercedes 300SDL; SOLD
1985 Mercedes 300D; SOLD
2006 Honda Pilot - wife's ride; 122K;
1995 Toyota Land Cruiser - 3X locked; 182K

removing the fan is easy. Just remove the allen head bolts that secure it to the fan clutch.

As far as removing and installing a belt, I think you can loosen the tension on the alternator and slip it on. But I managed to just remove and install mine on my w124(gasser) without adjusting anything

I am not sure that spilling ps fluid on the belt will cause it to squeek. The sound you hear is due to the belt slipping due to a misaligned pulley. Most likely the tensioner pulley is off alignment so the belt is sliding across the pulley as it turns.

If the belt still looks good (look at the ribs of the belt for cracks). If the ribs look good, your belt is probably OK and you should look elsewhere regarding the squeeking problem.

However, if you really want to replace the belt, it is fairly easy. First, I suggest you draw on paper the way the belt goes on the engine. Then using a 3/8" extension, insert it in the plastic tensioner arm and relieve the tension while you undo the bolt. Once the bolt is out, the belt is now loose. Easy peasy.

In my opinion though, check if the tensioner pulley seems crooked somehow. That might be the culprit instead of just the belt.

Ben

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Ben
1987 190d 2.5Turbo

You don't need to remove the fan. Just drape the belt over the fan to r and r.

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Ben
1987 190d 2.5Turbo

Is there a routing diagram for reference?!

__________________
1987 Mercedes 300SDL; SOLD
1985 Mercedes 300D; SOLD
2006 Honda Pilot - wife's ride; 122K;
1995 Toyota Land Cruiser - 3X locked; 182K

it looks something like this. the middle circle is the tensioner pulley

Attached Thumbnails

 

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Ben
1987 190d 2.5Turbo

If the backside of the belt has what looks like small balls of molten rubber stuck to it, your tensioner has tilted (worn bearing or metal warp). It tilts forward at the top of the pulley. You can't replace the bearing and forget about warp - get a new tensioner.

Fixed up my belt squeal...

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Cheers!
Scott McPhee

1987 300D

You can replace the belt in 15 minutes or 4 days........depending on your plan and execution.

The fan does not need removal.

The very first thing to do is to get a routing diagram or do your own sketch. The four day thing can happen if you think you can remember the routing diagram by looking at the routing.

The tensioner is released by removing the bolt that secures the plastic mount for the spring. You won't easily remove the bolt with it loaded..........so take the tension off by inserting a round bar into the top of the plastic mount.......pull the bolt........and slowly release the bar allowing the spring to return to it's free state.

Slide the belt forward from all pulleys and pull it over the fan.

Installation is not the reverse of removal if you want to avoid the four day affair. The belt must be squeezed together and inserted in the narrow space between the crankshaft and the water pump pulley and a loop slipped over the idler pulley. Then the top section of the belt is routed around the alternator and up over the water pump to the p/s pulley and the bottom section is routed around the crankshaft and around the a/c compressor and up to the p/s pulley where it meets the top section in a large circle

Once in place, the spring is tensioned with the round bar and the bolt is inserted to hold it in place. A nut on the back secures the bolt.

It's 15 minutes if you make a plan.

Totally incorrect my dear Watson:

http://www.peachparts.com/shopforum/attachment.php?attachmentid=10793&d=1061165816

Pay careful attention to the routing diagram. It's easy to install the belt wrong, but it will look correct and slip all the time.

It's not hard to do with the fan in place. Slip the belt between the blades then spin the fanwheel to move the belt where you need it.

I've always wondered why the 350s got a shorter belt. I have the longer 3L belt on mine (which is the same as a GM 3800 V6 by the way) and don't have problems.

-Jason

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1991 350SDL. 230,000 miles (new motor @ 150,000). Blown head gasket

Tesla Model 3. 205,000 miles. Been to 48 states!
Past: A fleet of VW TDIs.... including a V10,a Dieselgate Passat, and 2 ECOdiesels.
2014 Cadillac ELR
2013 Fiat 500E.

For informational purposes, the standard Mercedes lug wrench handle fits the hole of the plastic cam block perfectly! I don't know and have never seen any information confirming that this was a purposeful design feature, but it is good to know that with nothing more than the lug wrench and the 13 mm wrench from the standard issue tool kit the serpentine belt can be R&R'd!

It is usually easier using only a single wrench to first break the nut on the tensioner bolt free making use of the tension and friction, remove the nut completely, and then use the lug wrench or other suitable bar to relieve enough tension to slide the bolt rearward enough to allow the cam block to freely pivot.

Is it this part:
http://catalog.peachparts.com/ShopByVehicle.epc?q=&yearid=1987@@1987&makeid=63@@MERCEDES+BENZ@@X&modelid=6213%3AED|10000100%3AMBC|1512@@300SDL&catid=240909@@Cooling+System&subcatid=241024@@Acc.+Belt+Tension+Adj.+-+Lower&applicationid=W0133-1617503@@Acc.%20Belt%20Tension%20Adj.%20-%20Lower&mode=PA

Plus the pulley and the belt?!

Brian, I feel a 4+ day procedure coming on...

__________________
1987 Mercedes 300SDL; SOLD
1985 Mercedes 300D; SOLD
2006 Honda Pilot - wife's ride; 122K;
1995 Toyota Land Cruiser - 3X locked; 182K

That's the tensioner. There is a bearing inside that unit that can potentially fail. Most folks replace the entire unit.

You need to take a look at it and see if it's still perpindicular to the belt travel.

And if it is bad the tensioner is not hard to replace, and it can be done with the fan still installed.

-J

If you can get the cap off the tensioner and remove that bolt with the fan installed, you're a better man than I.............