Rattle on start up - 2.0TFSI

[AudiAK]

Hi all,

So since the drop in temperatures I've noticed that my 2.0TFSI makes a kind of rattly noise (as if something is struggling to spin over properly). I usually let the car idle before taking off (old habit) and either that or a few light blips of the throttle usually 'free up' whatever this is to make it sound normal again. It is very intermittent and usually only lasts a few seconds (if that) on first cold start.

It appears to be coming from the top end somewhere and sounds passenger side, but I cannot put my finger on it. Anyone had similar on their 2.0TFSI and found the culprit. I've done all the common issues on the car, just need to change the thermostat.

Thanks

 

[Charlie Farley]

Cam chain tensioner is the normal culprit especially when the air temps are low during the winter and engine oil takes a few seconds more to build pressure.
The tensioner pad etc can become worn and it leads to a bit more slack in the chain than is normal, as the tensioner is hydraulic and relies on oil pressure to keep it up to tension colder times of year can cause the problem, once the oil pressure is up to spec the rattle stops.
It can happen with a worn chain/tensioner or not, I had mine changed a while back and still get it no and again in winter, only lasts for a few seconds the stops.

That said it can also be due to blocked oilways which will have the same end result but blocked oilways are not ideal.
If you are really unlucky it may be the result of a defective oil pump which is failing.

but if it has only become more apparent in colder weather more likely to be the first.

 

[AudiAK]

Cam chain tensioner is the normal culprit especially when the air temps are low during the winter and engine oil takes a few seconds more to build pressure.
The tensioner pad etc can become worn and it leads to a bit more slack in the chain than is normal, as the tensioner is hydraulic and relies on oil pressure to keep it up to tension colder times of year can cause the problem, once the oil pressure is up to spec the rattle stops.
It can happen with a worn chain/tensioner or not, I had mine changed a while back and still get it no and again in winter, only lasts for a few seconds the stops.

That said it can also be due to blocked oilways which will have the same end result but blocked oilways are not ideal.
If you are really unlucky it may be the result of a defective oil pump which is failing.

but if it has only become more apparent in colder weather more likely to be the first.

Sorry for the delay but thank you for your reply

I did manage to fix the issue so thought I'd put it on here, in case anyone experienced similar.

It turned out to be the vacuum pump. Basically the hose at the top had become a little detached so on cold start it was creating a rattling noise (possibly due to lose of vacuum/pressure). Eventually after a few revs it was sealing itself and stopping this noise. New one fitted, job done

 

[Charlie Farley]

It also becomes a source of a really irritating oil leak as the milage increases.
you can rebuild them , well the seals etc to address the pesky oil leaking problem, just another one of the B7's great points..lol