220CDI water pump and juddering aux belt drivetrain overhaul.

[Droverunner]

Just been through this lot of work and thought the details might help someone in the future...

Some 6wks ago... a week after purchase... having completed a major service and fitted new rear tyres I declared our 2007 CLK sorted for the next 6k at least. But it didn't turn out to be quite that simple.

As the previous aux drive belt had been on for over 40k I decided to routinely replace it with a new one (Contitech). On going to do the job I could see the belt tensioner shaft had worn a little allowing the pulley to twist and so the belt to run off true plus it was "bouncing" a fair bit with the associated duh duh duh noise at idle... so I ordered a new tensioner too (Gates).

On removing the belt to swap it and the tensioner I found the water pump pulley had some play (not yet leaking) plus the two upper guide pulleys had noisy bearings.

The tensioner was a very easy two bolt fit but didn't cure the joggling belt so I thought I'd wait until I'd swapped the water pump and idlers before investigating further.

This tensioner... http://www.ebay.co.uk/itm/371734399021

Forgot a pic of the tensioner... just the belt.

 

[Droverunner]

Few days later the other parts arrived. FAI water pump, Febi idler pulleys and Comma G48 concentrate coolant.

I drained the coolant as far as I could by sucking the header tank dry with a hand pump and then caught the remaining spillage (about 2l) with a tray under the crank pulley as I pulley the old water pump away. The pump was easy to change once the multitude of bolts had been undone.

As bolts can be a different length I placed each into the correct place on the new pump as I removed... then once the old pump was off swapped them all into that for refitting one by one (if that makes sense).

There were no problems refitting the new pump or refilling and bleeding the coolant. I re-used the coolant I'd drawn off and added just over 2l of 50/50 Comma G48 and de-ionised water to bring to level... the car's aux elec coolant pump makes the bleeding procedure so easy.

The new idler pulleys went on OK but on starting I found the aux belt was still joggling and noisy.

 

[Droverunner]

I was aware a seized alternator overrun pulley can cause a noisy joggling aux belt but I'd not looked at mine carefully enough thinking it was a non replaceable solid pulley... not realising the black end was just a plastic cap over the overrun type. So having asked for advice here I ordered a replacement (Ina... same as the OE one I removed).

I bought this special tool to change the pulley... http://www.ebay.co.uk/itm/S-XA17H-Alternator-Free-Wheel-Clutch-Pulley-M10-Spline-1-2-Drive-33-tooth-Tool/122091781079?ssPageName=STRK:MEBIDX:IT&_trksid=p2057872.m2749.l2649

 

[Droverunner]

In the image of the tool above you'll see the 1/2" drive adaptor is away from the shaft of the M10 spline bit. It didn't come like that... the shaft was a very tight interference fit in the adaptor so it was effectively one piece. Problem was the old alternator pulley was so tight an open ended spanner kept slipping so I used a lump hammer and drift to separate the parts so I could get a ring spanner on the hex.

To save the hassle of drifting the 1/2" adaptor on and off I looked around and found the adaptor on my Torx/spline bit set was a slide on fit.

 

[Droverunner]

The pulley was so tight I had to arrange things with the ring spanner end braced into the alloy channel below the crank pulley and use a stupidly long tube over the end of the 1/2" ratchet. Even then it split the first spline drive adaptor before it came loose and I had to find another in the bottom of the toolbox.

 

[Droverunner]

Once the pulley was cracked off the first bit it spun off freely and replacement was easy. When all reassembled the engine idled with no belt noise and no belt/tensioned joggling.... at last.

Oh well at least that's all the bits on the front of the engine sorted for another 100k.

 

[om613]

Did the same job on mine.
Lucky yours isn't an IL6..

 

[Droverunner]

Is that a bit tight for space?

 

[LostKiwi]

Well done with that.

 

[steveq]

Great write-up.

Thanks for all the information.

 

[Droverunner]

Cheers guys. Had so much help when CLK hunting and post purchase if I can give a little bit back now and again... mind you it might be nice to have 6mths with nothing to report!

 

[Yugguy]

Fantastic write-up, yours is an OM646 same as mine so I'll be bookmarking this for future reference.

 

[e55amggary]

Just done the tensioner and pulley on ours, along with a new conti belt. Silly question are there 2 idler pulleys ? and are they the same ?

Thank you

 

[Droverunner]

Assuming yours is the same engine as ours yes there are two idlers... one each side at the top... and yes they are the same.

As in the image on my post #6... the ones either side of the water pump pulley.

I bought two of these... http://www.ebay.co.uk/itm/351587848484

 

[e55amggary]

Yes ours is a 646. just ought it a few weeks ago for the missus.

Getting it up together at the moment, a lot of car for the money. Have you a part no. for the alternator pulley ?

Thank you for the info

 

[Droverunner]

This is the one I bought...

http://www.ebay.co.uk/itm/332308440801

 

[e55amggary]

Good man

Thank you

 

[Droverunner]

Remember the tool!

 

[e55amggary]

I will see how it spins with the belt off. 160k on the clock, but excellent history. May also do water pump. Keep finding little jobs to do.

Same with all my cars. Get them perfect, then sell em!!

This ones suppose to be a cheap run around for her indoors.

 

[om613]

Is that a bit tight for space?

I thought you'd pick up on that!

There's a whole inch or so clearance to the rad.... cue some blood, a cut down torx bit, and no use of 1/2" drives.