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

 

[ticex]

Hi again,

Thanks so much to everybody that has read 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 so it is getting beyond the "putting up with" stage and developing into a real problem. 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.

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

 

[jimmy]

Spraying WD40 on the belt has probably worsened the problem and is causing the belt to slip at tickover, when you rev the engine the increase in speed gets everything working properly.

What speed is the engine idling? It sounds like tour idle speed is too low but then this is not adjustable so it must be your belt slipping maybe because of the WD40.

I would get the belt removed, tensioner checked and all the pulleys degreased and cleaned and a new belt fitted, if you can't do it yourself then get a garage to do it and send the original garage the bill witha written report from the second garage explaining how it was fitted wrongly, indeed if it was.

Keep all sprays and lubricants away from the belt, these belts need to run clean and dry.

 

[ticex]

Good Morning & thanks for the reply.

I think you may be right about the WD40...although it was only once I sprayed it on and it was very little at that. However, on the last visit to Merc in Brussels the head mechanic sprayed loads on! Now I know this is a bad thing to do it certainly shows the level of "expertise" I can expect from that particular garage.

The idle speed is perfect....that I'm sure of as I've compared it to a friends identical car the other day.

However, 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) 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?

I'm learning fast about this belt but alhough I'm not a novice don't feel I could take it off myself. I think I'll have to take it into another garage here before I head back to Belgium - I like the idea of giving the Brussels dealer the bill but I doubt they will pay. Out of interest how long a job is it for a mechanic to remove the belt etc... as mentioned above?

Thanks again for the help - greatly appreciated!

 

[jimmy]

If the tensioner pulley was not turning easily and dragging on the belt it would soon overheat the pulley or the belt resulting in failure of one or the other.

The belt is easy enough to remove, you may have to remove the fan or shroud to gain access. The hardest bit is remembering the path the belt takes, very tricky.

 

[Brian WH]

If the tensioner pulley was not turning easily and dragging on the belt it would soon overheat the pulley or the belt resulting in failure of one or the other.

The belt is easy enough to remove, you may have to remove the fan or shroud to gain access. The hardest bit is remembering the path the belt takes, very tricky.

Not a job for a novice, as if you get it wrong-------Well get your chequebook out big time.

 

[ticex]

I think I'll leave removing the belt to a mechanic! I know a good guy here in Edinburgh who will actually listen to me so hopefully he can get it sorted. I'm still wondering if my theory is right or wrong....suppose there's only one way to find out.

Thanks again for everybody's help.

 

[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 and everything has been fine ever since. Could it just be coincidence or is it possible? I'm very confused now!

Thanks again everybody.