This has been a long journey to sort out my 2005 XC90. I want to post this because I can’t find a definitive thread that has helped me solve my issue. I want to share some pics and video in the hopes someone else finds it useful when trying to solve this issue in the future.

My XC90 has had several issues that I have been working through. This is a list of what I saw and what I did and if it helped. The car was purchased at a dealership about 4 years ago with about 60,000 miles on it. I was really excited since I knew the 2.5 could go forever and it looked great. I had a 850 turbo wagon that I absolutely loved so I was happy to get another Volvo.

We were really happy for a few years but then it started needing some work. No real issue I didn't expect. The headliner started falling and the car was pulling hard under braking. We also noticed a knock when moving from a stop sometimes. We fixed the headliner and I replaced the LCAs and Ball joints. The car was now driving straight and felt safe again. I found a missing bolt in the upper motor mount and replaced it. It seemed to help but then I heard another knock. I dug around and found the transmission mount had a missing bolt. I don't know what happened to this car but someone either didn't put it back together correctly or maybe the missing bolt on top, cause stress on the transmission mount. Either way, I replaced the transmission mount and it seemed ok for a while. I still seemed to hear some knocking and eventually it started getting worse.

This is what is sounds like:
Outside car:

Inside car:

The knocking sounded like motor mounts to me and since I’ve had issues with those already I replaced all of them. The front mount was completely separated and but the others looked decent. I was sure this was going to fix it, but no. Still clunking.

I have jumped on the car and I can’t replicate the sound without driving. I have crawled under the car with a pry bar and can’t get anything to move. The sway bar is solid, the engine seems to be solid. LCAs are solid. Ball joints are good. Nothing is moving more than I would expect.

I went to the internet and got the list of other things to check for. Some people mentioned the tie rods since and since I could feel the knock in the steering wheel, I replaced the inner and outer tie rod ends. No better. Still clunking.

Back to the internet and I see several people claiming the spring seats can cause this sound. Cool. Ordered those and I replaced those. They were cracked but not completely separated. That didn't fix it either. Here is how mine looked:

Left Side:



Right Side:



While doing the spring seats, I noticed some play in the spring mounts. It really doesn't feel like enough to cause the loud clunk but I went ahead and ordered those. They'll be here tomorrow so I'll update if that fixes it.
Left Side:
Right Side:

I took a video of the movement not he top of the spring when I let the car down from a jack and it compresses the spring. This looks like way too much movement but I don’t have another Volvo to compare to. Hopefully this solves the issue.
Here is the movement:

I also know some people mention end links. Mine have cracked boots but are still solid. I have new ones on the way and will install those too but I don’t expect they will resolve this.

All Motor Mounts - Done
LCAs - Done
Ball Joints - Done
Inner and outer tie rod - Done
Upper Spring seats - Done
End Links - Pending
Spring Mounts - Pending

Anyway, I’ll follow up tomorrow after I replace the strut mounts and let everyone know if that helps. I sure hope so. This car is wearing me out.

 

your spring seats are the likely cause. you can see the hard rubber has separated from the metal bushing which will introduce play in the strut top. The strut mount (aka strut bushing) refers to the metal plate seen in the pics. Those should slide and rotate without any play and feel firm. Generally they don't fail but given the work is to remove the strut and disassemble, you might as well replace both the bushing and the spring seat at the same time.

 

Have you already fixed the issue? This noise seems to be coming from the brake dust guard. Check if it has a missing bolt or is lose. If not also check the bushing for stabiliser arm, the one that runs between the driver and passenger side.