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Discussion Starter · #1 ·
Hello all, I have a V40 T5 2017 and when I accelerate hard, just when the turbo/boost kicks in, I hear a weird spool sound, it is not as high pitched as the turbo normal spool and more like something making contact with another thing... sounds like something spinning as it increases in pitch as the rpm increase. It only lasts for half a second everytime the boost kicks in with a high load... it is less noticeable as the engine warms up and after turbo has kicked in everything is normal...

it does not happen when I go easier on the load (i.e. dont floor it from a slow speed) so makes me wonder...

Volvo checked for leaks in the exhaust and supposedly they found nothing so I’m beginning to think it is the turbo, perhaps some shaft play but the fact that after warming up the sound is less noticeable and that it only happens when I floor it makes me wonder

Have you had any issue like this? I will try to upload some audio recording later in the afternoon

Thanks!!
 

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Discussion Starter · #2 ·
Just in case some else encounters this and is wondering whats going on...

i went to the dealership and couldn’t find the source but they couldn’t find anything wrong as OBD data was correct and in general the car was ok.

Then I took it to a turbo specialist ij my city (supposedly) and they checked it and found nothing wrong with the turbo, they also read OBD data and everything was perfect...

Still with the question I kept searching on the internet for cars with similar sounds

Before my conclusion here are some notes:

Year: 2017
Trim: V40 R-Design T5
The sound has been more noticeable this year but I’ve heard it in the past
Polestar Optimised
And I guess the really important part is that this year I installed the intake and exhaust kit from Polestar, which means increased airflow both into the intake manifold as well as from the exhaust manifold...

searching online I found our V40 has an electronic boost controller and that basically regulates how much boost goes into the intake using a kinda valve called wastegate... this wastegate lets exhaust gases bypass the turbo in case the system detects there will be too much boost and cause compressor surges... so that sound that EBC (electronic boost controller) makes is very similar to the one I describe, seems like then I suddenly do full throttle, the car protects itself for a few milliseconds until the engine can take the boost hit.

You can search on YouTube for wastegate sounds but be careful as most of the “wastegate” sounds you will hear are actually BOV (blow off valve) which makes the sound AFTER you release the throttle

Hope this helps anyone :)
 

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Discussion Starter · #3 ·
Just in case anyone needs this is in the future...

Nah, the sound kept growing and I felt something was really bad... I took advantage of quarantine days and left my car at the dealership, I was lucky enough to have them replace the turbo on warranty and now my car purrs like an angel once again... my final conclusion is that I think the wastegate somehow carbon buildup or something and wasn´t closing properly but once the turbo heated, the metal would expand a bit and partially seal the wastegate again but at some point a hot turbo wasn't enough.

In the end Volvo decided to just replace the turbo and didn't bother cleaning the wastegate so i can't confirm my suspicions... oh well.

Hope nobody needs this info ever but if you need this, here's the info... oh and btw, the Turbo part number is 36012431 for a T5 2017 V40... made by BorgWarner like all Volvo turbos... and the price was around 1000USD plus tax.
 
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