W203 C220CDI Estate new owner troubles

[THXuk]

Well, after saving and hunting around for a specific Merc, I finally get a favour from a pal who's brother works at A Mercedes franchise as they have just taken in part ex what I am after.

They take in a 2003 C Class Estate auto deisel (just what Im looking for) but its to old to be on the forecourt, and they will let me have it for what it cost them, plus a drink.

So, I'm all chuffed driving it home..... and after about 20 mins of the air conditioner being on, a loud hiss is coming out of the centre console area.. it kinda sounds like a gas leak noise.. like tsssssssssssssssssssssssssssssss The pitch stays constant regardless of how low or high the output of the air is, oddly it gets worse if i turn the knob to output colder air.

Sitting in park, and turning the engine (keeping the electrics on) off it goes, but start up again and it comes back.

This is really getting me down, as I did not get a warranty as it was a special deal, and have a nasty feeling this is going to cost ££££

I do 600 miles a week, and the noise will drive me crazy

Any guidance and help would be very very welcome and appreciated by this big Newbie to Merc's...

 

[jaymanek]

I think there is a vacuum pipe that moves one of the flaps at the top of the dash... very common problem.. either live with it or take the dash apart and fix it!

 

[Nibbo]

Or the vacuum pipe has come off the back of the headlight beam height adjuster.
In which case it would be easy / cheap to fix.
To check it you need to remove the light switch panel.
This is done by pulling the handbrake release lever, under which is a screw that secures the light switch panel.
Once removed the panel can be levered out (being careful not to scratch it too much!).
The vertical rotating knob is the adjuster and should have a purple tube attached to the back of it; this is the vacuum pipe which may have come off.
Good luck.

 

[BlackC55]

Turn the AC on and off. Does it stop?

If it does it means your AC gas is low.

 

[THXuk]

Thanks for comments.

Turning the AC on and off makes no difference, neither does the recirculation button.

I tried a factory reset on the AC unit (holding down recirc and demist buttons) and it showed no errors.

Crawling round the net, I read comments such as it needs regassing, or leaks, faulty expansion valves, flaps.

My pals suggestion to turn the radio up was not the best he could have said....

Any further suggestions would be most welcome, or anyone who has had this them self.

 

[jaymanek]

Its definatelty a vacuum pipe.. switch the fan of altogether and the hissing will stop. (Put dial to 0 and ensure auto is not illuminated)

 

[THXuk]

You are correct that as soon as you turn the ac system off the noise stops. Plus it goes away when you stop the engine.

In your opinion is this going to be expensive?

Does anyone now part numbers for this, I try google, but it seems to refer more to vacuum pumps, then pipes, and those pumps relate to central locking, which is not what i need.

 

[BlackC55]

if you are sure it is the AC causing it. Get it re-gassed and check for leaks.

 

[jaymanek]

Its not AC gas that is leaking, it is just a vacuum pipe that controls a flap... These are a pain in the bum.

Its not so much parts that will be expensive, its dash stripping time... Last time we had this, our techy just removed the vent at the top and fixed it.. but im not sure its always that easy.

 

[BlackC55]

Its not AC gas that is leaking, it is just a vacuum pipe that controls a flap... These are a pain in the bum.

Its not so much parts that will be expensive, its dash stripping time... Last time we had this, our techy just removed the vent at the top and fixed it.. but im not sure its always that easy.

The AC controls on a 203 are not vacuum operated they are electrical.

 

[jaymanek]

Yes they are but there is a vac hose under there somewhere... we have had this a few times before..

 

[Rory]

Does the headlamp levelling work by vaccuum? Maybe it's come of at the switch end?

 

[Nibbo]

Does the headlamp levelling work by vaccuum? Maybe it's come of at the switch end?

Uhem... post #3

My money is still on that one!

 

[THXuk]

Well, I went for my first long drive today, and it was cold and wet so stuck on the AC, and never went past the 3 on the dial (quarter way), I just thought to myself that maybe blowing full air will start it and then it will not stop, so kept it low. 100 miles later, no noise....

When the car was collected from the dealer a few days back, my wife who picked it up, said the noise started after 45 mins of it being on, and she had it up high but cant recall the setting.

when it does occur the volume level/pitch stays the same regardless of how low or high you set the air pressure, and again only alters slightly in tone when you turn the thermo settings to a cooler setting/temp.

So it seems likes its coming and going... does this change anyone's thought's?

 

[jaymanek]

not mine!

 

[Nibbo]

Sounds more and more like Jay is right but for the amount of effort required I would still be inclined to have a quick look at the headlamp adjustment control. It would take all of five minutes to eliminate it from your enquiries and confirm that it is a dash out job.

 

[THXuk]

well, thanks gents, looks like I have a task for the weekend!

 

[jaymanek]

It will help if you research how to remove the radio and surrounding console... There are several how to's around the place.

 

[alibally]

I would get the aircon regassed. If its low they hiss like there is a vacuum leak. Its quite a common complaint.