Jet Engine Noise!

[GGB]

I'm interested in finding out what is making the jet noise from under the bonnet of my car whenever I turn off the ignition. It sounds just like a jet engine on shut down! I suspect the compressor for the A/C but it appears to be functioning correctly (in terms of inside temp/fan pressure etc.). I haven't heard anyone else's MB make the same noise and just hope it doesn't signify a costly bill on the way. The car is a 99T C220 CDI W202 Classic with 140K on the clock.

 

[jberks]

I assume its the aircon - the clutch is electronic I believe so when you turn off, the clutch releases so the engine doesn't stop it and the compressor spins down on its own. That's my theory anyway - (Mine does it too).

 

[Dan996]

hello
Mine also does this but i have no aircon.

 

[television]

there is a fix for howling,turbine sounds, need some VIN numbers


Malcolm

 

[Balal]

my car makes these noises as well... its clk230 kompressor with aircon

the VIN numbr is
WDB 208 347 2F 013 715

 

[Wezzel]

I've got the same model and year.

Sounds like the auxilary heater. This is a fuel powered heater designed to heat the car a little more quickly on cold days. It only cuts in when the outside air temp is less than 9 degrees. You will only hear it on very cold days.

Incidentally, I have to keep mine turned off as it stinks when it is running. There must be a leak somewhere but I can't be bothered to investigate it.

I bet if you turn it off the noise will disappear.

 

[Dan996]

there is a fix for howling,turbine sounds, need some VIN numbers


Malcolm

w20202 i think

 

[television]

Trust me to miss the word off,when I turn the engine off. The mods that i have are for when the engine is running.

I Have been through the whole compressor pages and nothing shown.

I cant be the Air con, as that is under load the whole time and will not spin with engine off.

Sorry about this. Malcolm

 

[gpm72]

i have a 2000 220 cdi, mine also does this, and it IS the aux heater, switch it so that it lights up, hey presto, no more noise, smell, and better still, better MGG. gary

 

[jberks]

What is the Aux heater?

 

[kevinororke]

Hi, what a useful thread. I was just about to post a question about the jet engine noise emanating from under the off-side front wing on my W202 cdi. I too suspected the heater booster. However, my experiment to prove this was thwarted because I did not realise that when the light on the heater booster switch is ON the booster itself is OFF. Ie when I thought I was switching it ON I was switching it OFF. I should have read the handbook.

Now that I've got things the right way around switching the booster OFF also silences the jet engine. As I understand it even when the booster is switched ON it only activates when the outside temp is less the 6c AND the coolant temp is less than 70c.

Regards, Kevin

 

[Wezzel]

The first time the heater cut in on my car it worried the life out of me. I had only had the car a few days (bought it second hand 2 years ago) and when I started it up smoke and fumes were pouring out from under the front of the car. The garage door was open and it stank out the garage and kitchen (as the connecting door was open).

I later found it to be the auxillary heater. Aparently they fail quite commonly and are expensive to fix. Most people therefore turn them off and put on an extra vest in cold weather!

 

[Blobcat]

What is the Aux heater?

On a 210 this is it, I'm not sure on the 211 though
http://forums.mercedesclub.org.uk/showthread.php?t=17917

 

[Dan996]

I take it you only have aux heater on deisel? Mine is not diesel but i also have this noise it lasts about 5 secs slowly fading to silence.