C30 Engine : - Strange noise on acceleration

Zack99 · Oct 15th, 2019, 07:38

Good day everyone

I've been browsing the internet for anything similar but I'm having a hard time explaining the problem so that makes it difficult to find a solution... so where else than a public forum.

Long story short, I got myself a 2010 C30 1.6 as a daily runner. Has done around 110000km. So now my question. Every morning or afternoon when I first set off, there is this sound that is similar to that of an aircon compressor kicking in exactly at 20km/h. It only happens once after startup and only when I pass that threshold.

I am pretty baffled at this.

I would really appreciate any input on what it might be. It's not a concerning noise, I'm just very curious if I should be concerned.

Z

T5R92011 · Oct 15th, 2019, 07:49

The clunk you are referring to is the ABS system testing it's self. They all do this on every startup as you reach a certain (low) speed.

IainG · Oct 15th, 2019, 07:50

Hi
I believe the ABS unit does a self test around that speed.

Iain

Zack99 · Oct 15th, 2019, 09:33

Wow, thank you guys!

I would never have guessed it's brake-related.

Initially, I thought it's the climate control that insists on having the aircon compressor running even if it's switched off. But that also made no sense in my mind as the sound of the compressor is generally inaudible when it's switched on.

Oct 15th, 2019, 07:38	#1
Zack99 New Member Last Online: Jun 23rd, 2020 14:02 Join Date: Oct 2019 Location: Cape Town	Strange noise on acceleration Good day everyone I've been browsing the internet for anything similar but I'm having a hard time explaining the problem so that makes it difficult to find a solution... so where else than a public forum. Long story short, I got myself a 2010 C30 1.6 as a daily runner. Has done around 110000km. So now my question. Every morning or afternoon when I first set off, there is this sound that is similar to that of an aircon compressor kicking in exactly at 20km/h. It only happens once after startup and only when I pass that threshold. I am pretty baffled at this. I would really appreciate any input on what it might be. It's not a concerning noise, I'm just very curious if I should be concerned. Z

Oct 15th, 2019, 07:49	#2
T5R92011 FCW Auto Service Last Online: Apr 17th, 2024 23:49 Join Date: Feb 2015 Location: Gloucester	The clunk you are referring to is the ABS system testing it's self. They all do this on every startup as you reach a certain (low) speed. __________________ FCW Auto Service (Gloucester) https://www.fcw-autoservice.com

Oct 15th, 2019, 07:50	#3
IainG Premier Member Last Online: Today 07:53 Join Date: Apr 2013 Location: Plymouth	Hi I believe the ABS unit does a self test around that speed. Iain

Oct 15th, 2019, 09:33	#4
Zack99 New Member Last Online: Jun 23rd, 2020 14:02 Join Date: Oct 2019 Location: Cape Town	Wow, thank you guys! I would never have guessed it's brake-related. Initially, I thought it's the climate control that insists on having the aircon compressor running even if it's switched off. But that also made no sense in my mind as the sound of the compressor is generally inaudible when it's switched on.

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