Polo 9n3 2008 1.4 BUD ticking/knocking sound

[Mrpolo159]

Hi I recently purchased with my other half, a Polo 9n3 1.4 BUD Automatic, there is a very noticeable ticking sound coming from driver side of engine (Uk) It increases with revs and when driving and let off the throttle it stops but as soon as you touch accelerator it starts again, is also present at idle but fades slightly when warm, I have replaced the water pump and cambelt along with all tensioners and rollers, the vehicle has only done 50k miles but I don’t have service history… I’m very stuck with this car as my other half is passing her driving test tomorrow and was really looking forward to driving. I have also done full service on it and replaced spark plugs too, I also get an intermittent PO328 code so have also replaced knock sensor, none of which has fixed the issue. What would my next step be?

[littlepolo]

Is it worse in colder weather than warm? Less noticeable over 2000 rpm and under way? They all do it... See my earlier threads on this. Make sure you are using the correct oil. Provided no DTC codes and otherwise drives well learn to live with it. Mpg?

[Mrpolo159]

Have a knock sensor code occasionally; but it generally sounds like from cam side of engine so really unsure what it is

[Mrpolo159]

Also I have the exact same engine in my polo, this one is my other half’s with the ticking sound, and it is far louder on her car than mine, hence why I’m worried

[littlepolo]

The noise on my 1.4 BBY is also noticeable on the o/s. I purchased a stethoscope but have not yet used it to try and pinpoint the origin. I read that the teflon(?) coating can wear off the pistons and cause a knocking sound. Not sure if No 1 is more susceptible but that is definitely the side where the noise originates. I think some pistons were replaced under a technical bulletin/warranty claim but cannot recall details. Replacement pistons that avoid the teflon wear are available but that's too much work. I'm not convinced it is the piston due to frequency, seems more like half engine speed, and so I think it is down to oil way design (not unheard of with VAG) and 'they all do it'.

Oil change/service history could well be a factor. I purchased my old 1.4 BBY engined '02 Polo at 27K miles but the early service history was incomplete. After a top end swap out at 90K (new belts etc) the noise is still there, even after 4 belt, pulley, and water pump swaps, but the car drives better than ever and fuel economy exceeds the manufacturer's figures.

I regularly used Mannol 0W40 (7719) as the odometer is reading 140,000 miles now. That oil is harder to come by (or v expensive) so I purchased some Shell Helix Ultra OW40 for the next swap before winter. It's a nuisance, but tolerable. I use an ethanol additive which also reduces the pinking so common with these engines. I would suggest to replenish the transmission fluid when convenient to ensure that the drivetrain is not causing undue load (your later model might be OK, but the vehicle is nevertheless old and low ATF could be an issue).