S124 E320T M104 Pulley & Aux Belt Noise Woes

tjamesbo

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1999 CLK430, 2007 VITO 3.0V6 , W124's (1994 320TE , 1993 220TE ) , 07 2.5 X-Type
decided to tackle this as the squealing like a loose fan belt is telling me this needs sorting now
I have a W124 E320 with the M104 in it with the Pre 95 Bolt / Rod Tensioner mechanism
I sprayed some water near the Aux idler pulley and the noise stopped
So off we go I replaced the Aux idler Pulley (top LH of engine ) apparently these are quite common to cause a squeal it was only £15 for a replacement and a quick job so Try that first as everything else involved a fair amount of dissembly
In prep I purchased a fan locking tool (£9.99 wire rod jobby ) of Ebay in prep for possibly having to change the tensioner if fix #1 didnt work

Fix# 1 didnt work and inspection of the service record revealed that the car had a new belt april 18 and has only done few thousand (1000- 2000) since then so the Belt should be OK
Next I removed the Belt and spun all the pulleys the only one sounding noisy was the Secondary air pump but i remembered that spraying water at the top idler stopped the noise and that the tensioners on these engines should be replaced at anything between 115 & 170K and as I'm at 115K and Im down there with access and the radiator out it seems good practice and could be the source of Belt Slip so off comes the tensioner assembly , but on removal & inspection it still looks good in a vice theres plenty of resistance in the rubber donut inside it .
I'm now thinking it may not be that but its sensible to replace whilst I'm down there with the Rad out I've ordered the Tensioner and Damper from Febi (£70 in Total from simplycarparts )
So whilst I'm at it might as well remove the alternator and get the pulley and bearing done ( eliminate something else ) a kit can be bought, but I favour finding an alternator specialist and getting them to do it hopefully inexpensively and another source of squeal isolated so that leaves me with the secondary air pump ( runs for approx 2 mins on a cold start then cuts out ) rebuild or replacement is expensive £400-£700 for something thats not really required I am therfore looking at this as a solution
https://www.kurth-classics-autopart...-w124-secondary-air-pump-replacement-kit.html
But am not sure how to get the correct shorter belt if this is done and whether anything else ( eg the alternator ) needs moving
There's also a query on whether deletion will cause the EML light to come on I d be surprised if this was the case due to its short start up operating cycle but MB tend to be thorough
I was also looking at possible replacing the Fan Pulley Bearing eliminating something else but the Tool for locking the fan that i bought off Ebay will not engage with the holes in the rear despite about 3-4 hours of trying with the aid of an inspection camera and then out of frustration several tweaks to get it to engage so i cannot do this without a decent tool klann or Baum ? and i can only find one source in the UK my original £10 ebay which i have lost confidence in (but havent tried MB themselves yet tomorrows job )
If only the aux idler or the tensioner were obviously worn / faulty
Boyd
 

LostKiwi

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'93 500SL-32, '01 W210 Estate E240 (RIP), 02 R230 SL500, 04 Smart Roadster Coupe, 11 R350CDi
New belt?
My Defender used to squeak terribly with a new belt. All new pulleys, new water pump and alternator made no difference. After 6 months if just living with it it stopped. Quite a common problem on Defenders.
 
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tjamesbo

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1999 CLK430, 2007 VITO 3.0V6 , W124's (1994 320TE , 1993 220TE ) , 07 2.5 X-Type
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Yes New Belt will be going on ,but still considering the Air pump delete which possible uses same belt or not got to check that it doesnt then require a shorter belt
 
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tjamesbo

Senior Member
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Location
Sutton Coldfield, West Midlands
Your Mercedes
1999 CLK430, 2007 VITO 3.0V6 , W124's (1994 320TE , 1993 220TE ) , 07 2.5 X-Type
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  • Thread starter
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New Tensioner and Damper arrived Saturday ( £50 + £20 ) Fitted them ( quite a fiddle in there with the damper and the adjusting rod behind and no visibility of the hole ) I eventually removed the Fan Pulley using a Large Rubber Pulley wrench and once the pulley was off i could see why my Fan Locking tool would not engage - The engagement part / prong at 90 degrees on the end was slightly too long and the tool wasnt quite sitting at the bottom of the casting groove ,therefore wasn't lining up with the locking hole on the Pulley Boss so £10 on Ebay and 3- 4 hrs of struggling and that was why once id filed off about an 1/8 inch it worked fine so theres another buy cheap and pay for it later.
Once the tensioner was fitted it did feel stiffer than the one that came out so I was hopeful it was going to eliminate the squeal
Alternator came back from the reconditioners ( car & commercial ) in Nuneaton recommended by Jay Manek Alernator Refurbed ( new Regulator & Bushes ) £40 all in Bargain and 24hr turnround
Everything refitted including Backflush of the Rad before refitting and Start up and Test Run and a Result!! nice and quiet now no squealing Job Sorted The lovely sound of the M104 straight six as it should be, purring away and roaring with a bit of throttle What great cars these still are, carpet like ride Straight 6 smoothness, and a hewn from Granite feeling as I waft down the road
Next job is sorting the aircon out
Boyd
 
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