Strange tapping when cold - CLS 350cdi

[dudeonline]

Hi all,

it's been a while as I didn't have a Mercedes, but I have a lovely 2015 350cdi CLS (45k on clock). This is an odd one, I'm hoping someone can shed some light on it..

From cold, start car, no tapping, rev, no tapping, drive off. If I then slow to a halt just say 100 yards up the road, just before it comes to the halt, I get a tapping under the bonnet, it carries on for say a second after I've stopped. This all goes away once the car starts to get warm. I don't believe it's the engine at all, some other part.

Cheers..

 

[mioba]

what engine oil are you running on

 

[EmilysDad]

A heat shield maybe ....

 

[dudeonline]

what engine oil are you running on

I'm not sure, whatever it had at the last service. But it doesn't sound like it's from the engine. As I say I can be idle in neutral and rev the engine, no such tapping. If I pull up to a stop (engine still running) I get the tapping sound just as I'm coming to a halt and then it continues for about a second after fading out, if I rev the engine at that point, no tapping.

 

[dudeonline]

A heat shield maybe ....

It's a mystery... I don't think it's anything major.. but puzzling and I think has been getting louder..

 

[John Laidlaw]

Heat shield would have been my guess too...

 

[ernieh]

Hi all,

it's been a while as I didn't have a Mercedes, but I have a lovely 2015 350cdi CLS (45k on clock). This is an odd one, I'm hoping someone can shed some light on it..

From cold, start car, no tapping, rev, no tapping, drive off. If I then slow to a halt just say 100 yards up the road, just before it comes to the halt, I get a tapping under the bonnet, it carries on for say a second after I've stopped. This all goes away once the car starts to get warm. I don't believe it's the engine at all, some other part.

Cheers..

I've had problems with the engine cover a couple of times; sometimes the rubber bushes that hold them can get lost during service and not replaced. The coming and going nature of the tapping can be explained by different vibration frequencies as the engine warms up.

Just a suggestion but if you take off the cover, all the holding lugs should be located in a bush.

Ernie

 

[sheryllee]

Yeah maybe the heat shield causes.

 

[dudeonline]

thanks all, it got a clean bill of health from the garage at the last service.