2.4 D5 Thumping noise
 

Bought an XC90 last week. Super body work and internally. However ...

Discovered a real problem. The engine has (what I call) a 'thump' where I can feel a pulse of air in the intercooler plenum. It just sounds bl00dy awful and decidedly not good at all!

The previous owner has replaced the pneumatic engine mounts and I've done the vacuum test and it makes no difference whatsoever.
There has been an injector replaced too.

I took it to a great Volvo guy in Skipton today and they have no idea either but have advised me not to run it as it really sounds that bad. I recorded it today but can't see a way of posting a sound file.

I wondered if it might be an inlet valve letting by? But then I would have thought I'd hear some kind of 'misfire' kind of much as you get when an injector seal fails!

I know it's a real long shot, but does anyone have any ideas?

The zip file here is an MP3 of the noise.

PRETTY PLEASE!:confused_smile:

Attachment 133422

You have worn soft valve lifters 0w30 oil with fuel its a known problem
You get escaping exhaust pressure in your inlet that way ,hence the noise

Can you explain a bit more pls? What's the resolution?

Replacing your valvelifters and if you want to prevent it the next 100000 miles using thicker oil like 5w40 an changing it every 10000 miles.

How did you not notice it buying the car?

Truth is I just don't know :confused_smile: Taking your eye off the ball somewhat through buying during lock down I guess ;-( Just extremely embarrassed and also annoyed that it was sold with such ...

Is there a kind of write up anywhere? I've not heard of it before and would be keen to understand exactly what the symptoms are before diving in. I suppose I should not drive it till its fixed?

Anything else I need to do whilst in there?

It harms nothing, only the sound.
It is known in this forum as the "tugboat sound"
Just to be clear you have the euro4 dpf engine?

To replace the lifters the injectors need to be removed and the the camshafts needs to be removed, than the lifters and the camrollers (much cheaper now than 10 years ago)
I did this myself 10 years ago

Most def the tugboat sound. Yes euro 4 dpf. Sounds like a fun job :shocked:

The reason it happens to the dpf engines is the thinner 0w30 oil in combination with the fuel dillution and the 30000km oil change interval.
Wich wears the lifters.
The previous euro3 engines dont have this problem due to the thicker oil with more zinc dopes and no fueldillution.
The job took me 10 hours, but i did it easy going , you need to be precise with torque up bolts on the camshaft bearings

The camshafts had no wear marks btw

Did it completely & utterly cure the tugboat sound tho?
How was fuel economy & performance afterwards?