Air Con Sounds Like Jet Engine!

[chickenlegs]

First time on this site - hopefully someone can help.

Have a S320 petrol 1999. A couple of minutes after starting the engine, the aircon makes a noise like a jet engine - very loud and doesn't sound too healthy. When I switch to economy, the noise subsides.


I have been told the condenser fan needs replacing at great cost - is this the case?

 

[television]

Are we talking about the heater blower fan, or engine condenser fan under bonnet.

malcolm

 

[polar]

air con

lift bonnet and listen to condenser fan as it starts this will confirm fault. fans available
from euro car parts fraction of cost plus oe quality. a/c /merc specialist can fit

 

[chickenlegs]

Hi, it's the engine condenser fan under the bonnet. I see the merc air-con units need topped up once and a while. I would hate to replace a part where only some maintenance is required

 

[television]

Topping up will not help a noisy fan, not very clear here as to noisy blades or something viabrating or even bearings, must be worth a second opinion.

Malcolm

 

[kamS430L]

I have the same issue only mine is more severe, every time I switch on the heater or air-con the condenser fan fires up and sounds like a jet plane. Also because the condenser fan is used for cooloing both rads when the car is stationary when the engine reaches a certain temp it fires up. Because I am a DIY mechanic and considering my S430L is a 2000 with 225,000 miles, I am planning on removing the fan and taking a good look at it myself as I dont trust no-one with my benz. Whilst I am doing this I also plan on cleaning the rads with a jet wash from the front. My guess is the bearings on the fan need greasing or replacing and shud not be too hard to do if the unit is not sealed.If I succeed I will let you know either way what the outcome is.

 

[dav]

think im getting this same problem - does the fan need replacing?

 

[loredan]

Mine too.
It's an S320 from 2000.
Anybody solve this?
I would try also myself.
I'm waiting for the WIS DVD's.

 

[Glenn Smith]

could it be that your fans are coming on full speed only? do they have a two speed set up like some, i don't know just a thought ( my jag sounds quite loud on full speed, although rarely needs full speed, if ever, i've only heard it when testing)

 

[Glenn Smith]

Just had a quick look at a wiring diagram, looks like the S class has a three speed fan set up no 1 when engine is off, speed 2 and three when running, sound like you could be experiencing probs with resistors or relays.

 

[loredan]

The noise is only when the airco is running.
If I stop the airco (EC pressed=light on) the whistle is gone.
MB dealer said is a valve to replace and a lot of working time=big money.

 

[Glenn Smith]

Do you know which valve? Is it the heater blower making the noise? does the noise dissapear after a while?

 

[loredan]

Should be the cold blower.
An the noise is going away when I stop airco (for cold air) and if I let him run longer is also coming and going probably due to automatic.

 

[jberks]

MB dealer said is a valve to replace and a lot of working time=big money.

Dealer = £100 per hour
Indie = £45 per hour
(same bloke, same training, same tools, often same overalls, just no B&O tv in the waiting room)
So, if the dealer is right and you do need this valve, use an indie, same job, just half the price.