Hi

 

I need some help in "guessing" what the issue is. I've attached a clip of the running engine with the respective sound. It's the sewing machine noise that I haven't managed to get an answer to.

 

The knocking sound wasn't as noticeable a month ago, the car only gets used about once every couple of weeks for some 100km trip. It also has lifter knocking sounds, but those are more up top, while this one seems to come from deep in the engine. For the lifters I went to a mechanic and he said they're not quite done and can hold out more, and that I should get an aditive to make them quieter. When I had that long trip I got the chance to buy something, he said to get something of quality so I got liqui moly hydraulic lifter aditive, but I didn't get the chance to use it, or waste it. On the way to the shop on this long trip, this knocking sound went from slightly audible to heavily hearable early on in the trip. The mechanic said he doesn't know exactly what it is and if it's a complicated issue to fix, I should just get a replacement engine since it would cost me less. Now I'm trying a few guesses from various sources to see if anybody knows exactly from experience what that sound might be. Two mechanics so far have said they don't know exactly. As a side note, while it's still an expensive issue to get an engine (used), I have doubts I'll find one without other issues, leading me back to repairs and more money.

 

 

https://www.dropbox.com/scl/fi/ocad57025bfecyfy5y9lh/VID_20241211_140228269_.mp4?rlkey=lwuw9vje7v4cel0rzc747yhkn&st=oudt9lmi&dl=0

Is that recording with cold engine?

 

Mk4 Polo but which engine?

 

Oil (correct spec) and filter change without any snake oil additives usually sufficient.

 

I can hear the ticky tick of valves and camshaft lobes. But not a deeper note.

 

Plenty of rotating things outside the engine to make noise.. air con condensor, steering pump, alternator, clutch release bearing ...

 

 

 

You can use a listening stick held to ear against these to check which.

No loose clothing to get trapped.

 

(and when moving brake discs, wheel bearings that can be checked at standstill/ engine off if can safely lift a wheel and turn it listening for crunchy rumbles).

 

 

The engine code is BMD, 1.2L petrol. In the clip, the engine is cold, since the car isn't used anymore with the issue going on.

The sound I'm referring to is present at the 8 seconds mark and 10-11. It's didn't use to make that a year ago.

Oil and filter gets changed every year even if the car gets about 2000-3000 Km/y... the per spec oil used is Total Quartz 9000 Energy 5W40, don't know if that might be an issue, doesn't look burned, it has a deep dark amber color.

 

Unfortunately I don't have a listening stick.

 

Air related parts, the fan doesn't start at cold temps and the compressor is turned off. The steering pump is electric, so it's not going to make a beep while the engine is running and steering not getting engaged.

 

I took off the accessories belt and made another recording, short, cause the battery isn't exactly new even though I've recharged it fully beforehand. So no water pump, alternator or ac compressor should be heard. This is the upload:

https://www.dropbox.com/scl/fi/fr06o6m48d4p70gcpyw8h/VID_20241212_140537551.mp4?rlkey=iqwqgavfu1v71y768gf5ga03e&st=ekkpds2q&dl=0

 

Found this clip today on Youtube and it's the exact same noise, maybe louder than in my car's case but it's the same.

 

 

And IDK what to make of it. The oil pump was replaced about 6 years ago and oil changed every year. How did it get to crank bearings getting worn out is beyond me.