Hi all!

The car: 2000 E430 Estate, 130k miles, runs lovely. Everything works

What wrong: About a week ago, I noticed a ticking noise with the following characteristics:

1. It sounds like its behind the drivers side vent (right hand drive!)
2. It only appears under moderate to hard accelleration
3. It only appears above 2000 RPM, and tends to go away at higher RPMs (although the latter is intermittent).
4. At full throttle/rpm it doesnt seem to be there at all
5. It is not temperature dependant whatsoever.
6. It IS dependant on throttle opening, suggesting intake/exhaust leak - but I've had that checked, theres no apparent leak.
7 Despite 6, the ticking sounds like one cylinder
8. Power is completely unaffected.

Thats as much as I can remember. Has anyone got any ideas on this?

Kind regards,

Mike F
Devon UK

Hi again,

One other observation - the ticking sounds like electrical pulses.

Above 2k rpm only, and the ticking increases from 1/2 throttle to 3/4.

It must be very near the bulkhead on the right, as I still cant be sure whether the sound is from inside the car or in the engine bay.

Due to the only circumstances under which I can recreate this fault (IE, rapidly building speed) - I cant do much testing at idle/standstill. Due to this, I'm relying on suggestions from the experts.

If need be I'll get the dealer tech to come out for a ride - and maybe download the codes etc... does anyone think it might help?

Thanks for anthing you can suggest.

Kind Regards,

Mike Freeman

It sounds like an exhaust leak. Typical would be a cracked cat weld. It may be hard to see but it will be easy to hear with an ultrasonic leak detector or a stethescope with just the hose attached, under the car with the engine running.

__________________
Steve Brotherton
Continental Imports
Gainesville FL
Bosch Master, ASE Master, L1
33 years MB technician

Interesting...my wagon has the same issue. I have begun noticing a rattling noise in the morning when the car is in gear. I knew the catalytic converter might be loosing life (114,000 miles), and recently my LHD wagon has developed the ticking sound at 2000 RPM above (almost inside) the passenger side glove compartment. Thanks for the information. It looks like the cat is on its way out.

Are there any consequences to driving with a bad converter. I have noticed slightly sluggish throttle response, but is the engine being damaged?

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1982 300D-T (sold)
1988 300E (sold)
1994 E320 Wagon (sold)
1995 E320
1998 E300D-T
1999 E3204M Wagon
2001 E320
2005 E320 CDI