Hissing When Accelerating

[gazza0210]

Hi Everyone,

I have a 2009 C207 E350 Cdi.

Just a quick question, When I rev the engine the car revs normally but once I take my foot off the accelerator I get a 'sssssssssss' sound as the revs drop off. It almost sounds like a dump valve but is more of a hiss than a 'pssst'.

Is this normal ??

 

[camerafodder]

Have you checked the glovebox for one of these?

 

[camerafodder]

On a more serious note have you had a poke around your air intake system and turbo to see if all the hoses are secure/free of splits and cracks?

 

[alecmascot]

It's the alternator clutch.
You need to have the pulley changed.

 

[gazza0210]

Thanks for the help so far,

Could an Alternator clutch cause a whistling sound?

This is my first ever diesel and don't know what sounds normal and what don't.

 

[alecmascot]

When you blip the throttle the alternator cannot decelerate as quickly as the engine does so, an over-run clutch is fitted. If you have someone blip the throttle and watch the drive belt you will see it thrash about a bit and the alternator pulley will slip on the belt.

 

[gazza0210]

When you blip the throttle the alternator cannot decelerate as quickly as the engine does so, an over-run clutch is fitted. If you have someone blip the throttle and watch the drive belt you will see it thrash about a bit and the alternator pulley will slip on the belt.

Thanks mate,

I'll have a look in the morning and report back.

 

[Kingsford G]

Hissing and whistling are not the same sounds.Usual turbo pipe split is the pipe on the right as u face the engine thats hissing noise.Take the belt off and check the pulley,should lock up clockwise and turn anticlockwise if not turning anticlockwise pulley is seized thats yr whistling noise.

 

[camerafodder]

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