When I turn on the engine the running sound is fine, but there is a rhythmic light knocking sound also. 

It gets faster as I accelerate. 

Any ideas what this could be? 

I have a recording on WhatsApp but couldn't attach it

 

Thanks. 

 

Órlaith.. Ireland.. 

 

 

Hard to say without hearing it. Could you upload it to YouTube and post the link here? (you can upload as unlisted so only people with the link can view it and it doesn't show up in search results)

2 hours ago, petrolbloke said:

Hard to say without hearing it. Could you upload it to YouTube and post the link here? (you can upload as unlisted so only people with the link can view it and it doesn't show up in search results)

 

2 hours ago, petrolbloke said:

Hard to say without hearing it. Could you upload it to YouTube and post the link here? (you can upload as unlisted so only people with the link can view it and it doesn't show up in search results)

Hope video is okay 

Edited 2 December, 20241 yr by Irishgirl

10 hours ago, Irishgirl said:

Hope video is okay 

That knocking sound is regular, and about 120-130BPM.

Off the top of my head, I'd be looking at the cambelt catching on something as it rotates.

Other than that, it might be some trim vibrating oddly with engine vibration, it doesn't sound metallic in the video.

But it's hard to tell from the video.

Not engine speed nor half engine speed (camshaft).

 

Could it be the crankshaft driven vacuum pump?

 

Yes I realise that would imply a frequency corresponding with engine speed but I have heard recordings of that making that noise, mine make a waah-waahing noise and at that frequency.

I'm not a mechanic, but it doesn't sound terminal. 🤞

 

Sounds to me like it could be the cambelt or aux belt. Have either of those been touched recently? It looks like 210,000 has been tipex'd on to the cover, what's the mileage (or kilometerage) of the car now?

 

Your best bet is to take it to a garage if you're not confident fettling with it yourself - if there is something fouling the cambelt or the cambelt is loose and fouling on something then it could be bad news if it snaps. If there is any damage to the cambelt then it should be replaced.

I think its way too slow for that, you can hear the frequency of the idle RPM in the video, most of the general clattering is following that, there is also valvetrain noise at half that frequency, harder to distinguish as its synchronised with (masked by) with the RPM clatter, the knocking is very distinct and much slower, its a different sound to but the same frequency as my vacuum pump noise.