Changing Fan Belt - Urgent

[surreychris]

Hi all

2001 E220cdi w210

I was taking my daughter to a pantomime last night and sods law the fan/drive belt snapped on the way and we had to park the car and get a taxi the rest of the way to the theatre.

I have just picked up a new belt and towed the car back to the house but i have two questions.

1. As the belt had stripped and come off i do not know which way the new one goes round all the pulleys etc, does anyone have a diagram or can tell me?

2. I have changed many petrol fan belts before where you adjust the position of the alternater to tighten the belt but cant see how this can be done on the engine, how do you tighten the belt on this car.

Thanks in advance

Chris

 

[grober]

If I have got the engine correct the poly V belt run will be similar to this. The belt tension is adjusted via a spring loaded tensioner which is the small pulley in the centre of the diagram here. çàï÷àñòè Mercedes: êîäû çàï÷àñòåé ìåðñåäåñ
You usually have to relieve the tension by rotating the tensioner anticlockwise [ via a spanner/socket on the bolt securing the pulley to the body of the tensioner] and slip the belt on

 

[surreychris]

Thanks for the diagram, thats is how it goes on

My next problem is even with the tensioner not pulled back the belt is too loose so i need to adjust the tensioner.

Do i do this by undoing the tork nut and moving the tensioner clockwise?

If so does anyone know what size of tork socket i need to buy?

Thanks again

Chris

 

[grober]

There is more than one size for that model depending on what equipment it has.e.g. air con

Automotive Aftermarket Searchable Catalogue
My guess is you have the wrong one.

 

[surreychris]

Thanks

It is now on, i mustnt have had it round one of the pulleys correctly.

I phoned a mercedes dealer who told me that you cannot adjust the tensioner and that my belt must be the wrong one, it should be 2271mm according to their records, as it is it was the right belt just i hadnt put it on correctly but thankfully it now is and im just waiting for the battery to charge.

The mechanic also told me that the belts do not just fly off the engine (tho i do have a high mileage car and not sure when it was last changed). He said there is 3 reasons they come off;

1. A diesel leak caused it to 'corrode' and break
2. The belt was too loose to start with
3. The alternater pully/clutch has gone

He said that number three in his experience is the most likely and i remember reading somewhere that the alternater pulley is only supposed to spin one way but before i put my new belt on I could spin it clockwise and anticlockwise.

Does this mean i have a fault in the alternater, and if so how can that be fixed.

Do i need a new alternater or can just the pulley be changed.

Thanks again for all the help

Chris

 

[kwakdonut]

I believe alternators will spin either way. Can't see any reason for it to spin only one way!

I imagine the belt was just passed it's sell-by date and gave up the ghost!

 

[surreychris]

I'll see how it goes once the battery is charged and then over the next cpl weeks.

It was on benz world that I read about the one way clutch on the alternater pulley, something to do with it helping keep it spinning at a constant speed when the engine speed drops and that it is prone to failing.

of course, they were referring to a 320 engine and not my 220 but they may share the same alternater. guess time will tell.

 

[kwakdonut]

I would say that the alternator may be similar but not the same. The 320's alternator, I would have though, would be beefier to take the higher demand of the larger starter motor and additional electrics (I think!) that the 320 would posess.

Have never heard of this 'one-way' alternator - new to me!

 

[grober]

To check if it is the freewheel pulley, just remove the drive belt (easy procedure) and then check whether the pulley freewheels in the ACW direction but turns the alternator shaft in the CW direction. If the clutch mechanism is seized then it will turn the alternator shaft when turned in both directions.
Have a look at this http://www.mbclub.co.uk/forums/electronics/86839-alternator.html
here's the explanation http://www.ntn.co.jp/english/products/review/pdf/NTN_TR75_en_P124.pdf

 

[surreychris]

Hi All

I just cant believe it, i just took the car to the shops, 5 mins away and now the new belt has ripped apart just like the old one so obviously something is causing it.

what should i be looking at now?

 

[BlackC55]

Check all the pulleys for wear in the bearings firstly

 

[surreychris]

What am I looking for in the worn pulleys, ones that make a noise when i spin them or ones that dont turn freely or both?

Any common ones that typically go, the car does have 235k miles on it and i have owned it for the last 37k miles and apart from a new starter it hasnt given me any problems to date.

Thanks

Chris

 

[surreychris]

Hi All

Ive just been out to look at the car again (boy its cold down here in london) and have just seen a problem with the waterpump.

The water pump has two wheels on it, one that has the grooves and one that has a flat surface.

The one that has the grooves has broken in that only 3 grooves are left on the wheel and a 'ring' has broken off at the rear end of the wheel.

I am guessing that this broken 'ring' that wont spin is cutting into the belt causing it to strip, the broken belts seem to support this as they are not snapping but comming apart into multiple belts if that makes sense.

Now I have to see how much and where i can get a waterpump from.

The alternator clutch i think is siezed i'm sure but i dont think this is causing the belts to break so i hope i can wait till the new year for that and get the kids through xmas first.

Chris

 

[surreychris]

Hi All

Ive had another look at this pully 'on' the waterpump after looking at the waterpumps on eurocarparts and ebay.

I dont think the grooved pulley is part of the waterpump, it certainly isnt in the waterpump pictures.

It seems to be bolted to the waterpump casing through one of the holes but a separate part.

Does anyone know how to remove it and where i may get this pulley, is it a dealer only part.

Thanks

Chris

 

[grober]

çàï÷àñòè Mercedes: êîäû çàï÷àñòåé ìåðñåäåñ

 

[surreychris]

Thanks

I took the bolt cover off it and took a picture of the pulley in question.

So its off to the merc dealers tomorrow to see if they have the part

 

[surreychris]

Hi All
I managed to pick up a new guide pulley from german sweedish french for only £15 and another belt (another £15).

The pulley is easy to remove, only a T50 male tork socket needed and all is fitted and seems to be working well, fingers crossed.

In the new year I'm going to change the alternator freewheeling pulley, waterpump and the tensioner pulley for good measure.

For anyone looking the alternator freewheeling pulley, German and sweedish stcok them for only £38 plus vat which seems much better than the £100 ive seen quoted.

Thanks for all the help

Chris