E300 Turbodiesel serpentine belt problem saga

[ticex]

Hello again!

I have had an ongoing saga with the repair of my serpentine poly-v-belt mechanism and belt by the main dealer in Brussels last month. To cut a long story short some tensioning spring thing that connected to the tensioning pulley was duff so after 3 trips to the garage they managed to stop the belt slipping and fitted a new belt.

Ever since they performed the last repair I've found the Power Steering rather heavy and when the engine is started from cold the belt makes a kind of squeeking noise. I understand this belt also drives the PAS pump so suspected right from the start they hadn't done something right but after a huge debate with the mechanic at the dealer I gave up and hoped all was ok. However, now the weather is getting colder I've noticed the lights are much dimmer when the engine is cold, the steering is even heavier when starting from cold and the funny noise from the belt is more pronounced until the engine has warmed up a bit. The steering problem is a bit of a pain as my car has speed sensitive steering so it is bearable when parking but out of town it does really get quite heavy. I'm currently back in Edinburgh but will be in Brussels with the car next week so am considering going through the hell of visiting the main dealer again to try and sort this out - it is kind of a principal thing as they have charged almost £200 for all the various repairs on this thing!

As this belt also drives the alternator I think I'm correct in assuming something is definately not right but I'm in the difficult situation that the dealer is not interested unless I can tell them exactly what is wrong! It's hard to convince the mechanic that the steering is heavier than before when he turns round and says "but it turns easily enough" and then won't even entertain the fact it gets too heavy at higher speeds. I'm also worried that it is getting worse and one day could just pack up on me when I'm depending on the car.

I'm hoping somebody on here could give me an idea of what the problem could be so I can either go back to the garage in Brussels and tell them what is wrong or if it's a simple thing fix it myself! For the moment I've found spraying some WD40 on the belt seems to make the steering lighter for a while but it just gets heavier again within a few minutes.

Thanks very much in advance for any help!!

Greetings,
Michael

 

[guydewdney]

noooooooooo. dont spray wd40 on the belt.... if anything, spray belt dressing spray - availible from any bearing supplier shop (bsl or wyco etc)

if the car is a 210 series the belt is 21.36 x 2130 and is routed (going clockwise from crank)

crank
tensioner pully (180 degrees wrap)
fan (touching bottom)
?alternator? on left
fan(touching top)
air con? top right
pas - bottom left

 

[panason1c]

......"when the engine is started from cold the belt makes a kind of squeeking noise".....


Sounds to me that the belt is not being properly tensioned by the tensioner, the 'squeeking' (or 'squeeling') noise is the sound of the belt slipping, you will need to go back to the dealer to check that the tensioner has been fitted correctly and that the correct size belt has been fitted.
With respect to guydewdney using belt dressing to stop the slipping would be treating the symptom and not the cause.

 

[ticex]

Thanks for the replies.

I didn't know spraying WD40 on the belt was bad! Why is this? The mechanic in the merc garage actually was the one I saw spraying it on when it was slipping at the start. Nice to see they know what they are doing!

I agree the slight squeeking when cold is the belt slipping slightly but the problem I have is it only does it when the car is stone cold and at all other times sounds fine. The symptom that is noticeable is the heavy steering but it's proved impossible to convince the dealer there is a problem with this - trust me I argued for an hour!

 

[panason1c]

Lights dimming (belt driven alternator)....steering heavy (belt driven pump)....squeels from the belt......All these problems only since new tensioner and belt fitted......


The clues are all there, have you felt the tension on the belt yourself?, it should feel fairly tight....if it feels quite slack then there is your problem, i would have another dealer look at it.

 

[guydewdney]

i reckon that he sprayed wd40 on it to stop it squeeking just to get rid of you...

you should be able to turn / twist the belt 90 degrees with a bit of effort...

 

[ticex]

Interestingly enough when I try to twist the belt it seems ok (I'm not an expert) but I can twist it 90 degrees quite easily....if anything I guess it's just a tiny bit loose. Is it possible to adjust the tensioner slightly? If so perhaps I could just do it myself?

The problem now seems to be more pronounced with the colder weather. I just noticed tonight that if the ASR kicks in while you have the lights and wiper on the radio switches off and the dash lights flicker. However, if you do it without the headlights on all is ok. I tested a few combinations and if you have te heated rear window on and the full beam the same flicker and radio switching on and off. Am I correct in assuming this is a power problem which could point to the alternator not running at full speed? When you consider the recent belt work, the squeeking noise when the engine is cold and the PAS being heavy it does seem rather likely doesn't it?

What a pain this is.....part of me wants to get the original dealer to fix it when I'm in Brussels next week as they have messed me around so much AND overcharged for the work but the other says just to go to a decent mechanic who will actually do the job right!

 

[ticex]

Hi again,

Thanks so much to everybody that has replied so far...your help is greatly appreciated. I'm sorry to keep going on about this problem but the main dealer in Brussels annoyed me so much at the time of the repair by arguing with me, basically doing nothing and overcharging I really want to get my facts completely straight so I can get it sorted. It's even more annoying as I really was sure there was a problem from the moment I collected the car last month but what can you do when the service manager just stands arguing that you're imagining it and refusing to do anything!

Tonight in Edinburgh there was the first real cold and wet night the car has been out in since the repair. The problem seems to be getting worse as the symptoms now are more pronounced. I discovered a trick with the climate control which gives a "volt" meter on the screen by holding down the "rest" button which has helped me diagnose the problem.

Basically, I did the following test. If you are stopped with the engine idling, your foot on the brake and the indicator on the voltage drops down to about 10v, the indicator starts flashing ultra-fast (I guess due to the low power), the instrument lights/headlights dim and the steering gets heavier. The moment you rev the engine a little the voltage goes back to normal and by testing it I now notice the steering gets gradually lighter but the moment the engine drops back to idle everything screws up again. I tried the exact same test with the engine off & the key in position 2 so everything is just running from the battery and the indicator flashes perfectly. I'm not an expert but I'm learning (thanks to all of your help) so my conclusion is that for some reason the belt isn't spinning at the correct speed when idling and as it drives the alternator and PAS pump the results are shown by the heavy steering and low power. Furthermore, the fact all is ok when the devices are running from the battery shows the battery is okay and the fact that it is ok when you rev the engine a little shows the PAS pump & alternator work okay meaning the problem is with the belt driving them.

Finally, I went back to the car an hour or so after it was constantly showing the above symptoms without fail. Like magic all was ok with the power but the power steering was a little lighter but still not like it should be. I'm not an expert but imo this points to a problem with the tensioner thing they fitted but is actually rather annoying as it's so hard to convince mechanics a problem is there when it's intermittant!

I would be so so grateful if some of you could give me your opinions on this and let me know if I sound like I'm concluding the right thing. Also, if anybody has an idea how they could have screwed up fitting the belt, tensioner shock absorber & spring that it would cause these symptoms it would really by such a HUGE help as I can go to Mercedes with a complete description of the problem and it's cause hopefully resulting in it finally being fixed!

Once again thanks so much for all the help - if we ever meet I'll owe you all a drink!

Greetings,
Michael

 

[ticex]

Good Morning and I'm back again (already)!

I just had a thought about what the problem could be. The dealer replaced a tensioner spring, shock absorber and the belt but not the actual tensioner. Could it be the actual tensioner pulley isn't turning easily enough resulting in an increased load on the belt? The more I think about this the more it makes sense - it explains the squeeking when cold (perhaps the pulley itself), the heavier steering/intermittant power problem (caused by everything turning slower) and the WD40 could have temporarily fixed it because some got inside the pulley bearings free-ing it up but now it's wearing off resulting in the problem worsening. Does this make any sense? Is it even possible?

If this is the case then is there an easy way for me to lubricate the pulley? Hopefully a replacement isn't needed as I've spent way too much on this already!

 

[OlafMaxwell]

A few things:
1 Never ever put lubricant onto the belt. That goes for WD 40 too.

2: Squealing/screech is a belt slipping, insufficient tension, duff belt, duff tensioner OR a pulley not running freely on its bearing water pump bearing/alternator bearing or power steering pump bearing or tensioner bearing. If tension is correct then a check on the other pulley bearing may help.

3 Cold weather will increase noise because of using higher electrical loads, big risk of flattened battery.

 

[ticex]

I took the car to the mechanic I know and the only thing he guessed could be causing a possible problem is the tensioner spring. Although it was replaced last month he reckoned it could have been weakened by the faulty shock absorber which jerked it up and down for a week or so. It was difficult as the car was 100% ok when he looked at it!

However, I was meaning to get around to replacing the small (wrong) battery that was in the car. I replaced it yesterday with the correct big battery and everything has been fine ever since. Could it just be coincidence or is it possible that this fixed everything? I'm very confused now!

Thanks again everybody.

 

[sl3204me]

tensioner problem

I have some common sense advice for you.When nreplacing your belt also replace the tensioner.The Porsche and Mercedes models both are finicky when it comes to proper belt tensioning.You only replace the belt every 60,000-80,000 miles,so do it right.The mechanic will set the correct specs according to your car.The 2nd part you have already done...make sure your battery is at full operating efficiency.Now the 3rd part..make sure that your alternator is putting out the correct amperage.I agree that you shouldn't apply belt dressing to the fan belt.If it shows wear or cracking,have it replaced.Squealing is due to belt slippage.Make sure that some WD40 didn't get on any of the grooves on the pulleys,ect.The surfaces need to be clean and dry for the belt to make proper contact.