Loving new to me V50 T5 AWD. 136K. Now spooked abrupt noise I've never heard

[GreenMagicMan]

I just got this car at auction. I believe it was a one owner car. I have some records and clues.
Looks to be extremely well taken care of, probably garaged until a year ago (?)

Car was running great. Quiet, goes off high idle on cold start in 3-7 seconds (like the new to us XC70 2004 one).
Smooth, smooth shifting etc...

Only driven it now about 200 miles total. There have been 3 'incidents' I believe.
They all seem to share almost a 'hop' of the front end when turning no speed. Like a noise and sudden release, almost like the car slipped off a stone - but on flat / paved surfaces.

Was driving it and parked on dirt road. When I reversed we heard a very loud sound under the car, approx under the firewall area perhaps but could have been even more towards the front of the car than that.
Then it almost sounded like we were dragging SOMETHING like either a large branch or stick or like a part of the car.
I was sure there was going to be something underneath car and there was not.
I turned the car around a bit to get back on main road and there was that maybe faint (?) pop noise or like a mechanical sudden release anyway and then the car sort of hopped skipped to the left a little (felt like driver side).

(I believe this 'hop' / random sound happened first in town we bought car in on drive home in parking lot.)

Then, an hour later after the dirt road reverse incident, we were driving up a pass. Suddenly there was out of blue on straight flat uphill some sort of indescribable noise ( I can tell you what it was not: not a screech, rattle, pop, bang, grinding...) what was it? I can't qwuite say, maybe a sort of thud or mechanical thunk impact sound (??) Then it sounded like there was something dragging under the car again - like something metal dragging.

I checked under car - nothing. After a few minutes, I reversed out and very gently drove the car about 4 miles home.
Now, II'm quite freaked out. Have not a clue what could be wrong.
I've done quite a few repairs over the years and diagnose cars - this has me without any ideas.

Today, I plan to remove driver wheel and see if I can see anything broken. Any ideas?

[matthew1]

Check for an axle not seated against the hub. That's my guess.

[BlackBart]

^^^Good idea.

I first thought maybe something in the steering tie rods was binding with the lower control arm and then letting go. Wrong tie rod ends? Installed incorrectly?

But turning and a noise might imply axle or axle splines or CV joint.

[GreenMagicMan]

Well the turning was more like a sudden slip to the side - sort of. with some sort of noise although not loud.
I'll take a look at the axle and the suspension members later this afternoon and see what it looks like and post back.

Thanks!

[GreenMagicMan]

Ok, so I took both front wheels off and did full inspection.
Both axles are mounted correctly / tight in their hubs.
It's a front strut suspension so many parts are not present like my Honda Accord for it's multi-link suspension (No UCA, no UBJ, several other parts not there).
The brakes are excellent - they look new, close to new rotors and no wear on pads.
The only thing is driver side has a very long skinny vertical suspension part - it looks to be the "Sway Bar End Link", and it's a noticeably looser on the driver side than the passenger.
The steering rack looks fine. No leaks on their boots and no leaks on in and outer CV Axle boots. They are dry and no tears.
All the bushings I could see on both sides on all parts - those I could see - all looked at least visually fine too.
Springs in struts look tight, fine and no cracks / breaks etc... There is more rust under this vehicle than I thought, outside this car is a stunner!!

Obviously a bit mystified as what this issue could be and so far a big vote of no confidence to drive this car anywhere important.

looking up more... suspicious about the driver side sway bar link. Could it cause sudden horrible front end noise, and then maybe go away?

[GreenMagicMan]

The upper engine mount certainly looks very worn (passenger side) . Doing online research, and comparing.
The mount seems to have damage to the underside rubber / plastic. It appears to be maybe metal on metal there.
Had 6 year old start the car for me... a couple initial clangs of vibrations of metal / metal sound there.
I may have to test drive more.
I heard a few videos with bad upper engine mounts (one was a Volvo) and I think those might be some of the noises I heard, but mine were perhaps more rapid and were loud in the car.

(Passenger in car with me states sound came from center of the car down low, which was what I had thought too, but had wondered if it was noise from right side of car and as driver I couldn't tell if it was right side of engine or center as I was driving at the time.)

[motormikeyman]

Is the noise your ABS pump engaging? Your traction control could be coming on as the result of a bad wheel sensor or ring perhaps? The sway bar end link will make a knocking sound over bumps but not much more.

[MRScott]

Sounds like you have a handle on the right upper motor mount. For sure get that replaced, easy repair, common issue. Just did one, customer had a noise when the car was on a turn leaving the driveway. They are filled with a fluid that leaks out when the rubber fails and this creates a metal to metal contact, thus the noise. Also check the other mount points.

[GreenMagicMan]

I swapped in a used - unfortunately leaking - upper engine mount that was more solid overall and had more rubber. The engine sits higher up now. A couple drives, and one 100+ mile 2 hour fine... and then the noise came back 2x on a shorter drive. Not as loud as last time - but it's the same noise.

Not definitive of course, but unfortunately I'm pretty sure it's not the upper engine mount.
I also was under the car, and with engine off, the A/C compressor spins freely back and fourth by hand. I'm not sure it's supposed to do this?? (I took a video and could post if needed).

Has something throwing an ABS code, but no other codes coming up for about a thousand miles now.

[Krons]

At that mileage I’d suspect CV joints. May be worth pulling the shafts and checking for slop in them. Just did them on my 2008 C70 with 120k miles, one boot was torn and decided to just swap them. Both had a little bit of play in them.