PSA 1.6tdci metallick "clicking" - possible hydraulic lifter?

Question

My 2007 Volvo V50 1.6tdci (380.000km) suddenly started to have a metallic clicking sound when I got off the freeway the other day (see video: https://photos.app.goo.gl/SmGt2Lz7itSWWQ2x7). The sound seems to get louder, the higher the RPMs. Sadly I didn't get a video of that.

I tried to pinpoint where the sound came from exactly with a long screwdriver as a stethoscope, however I couldn't pinpoint it to one specific spot. I also tried to run some oil cleaner through it, in the hopes that there was a minor oil restriction to one of the hydraulic lifters or something. After the recommended 20 minutes, no change.

My own best bet was a bad hydraulic lifter, so I decided to take off the valve cover (which is easier said than done on this engine - and this is the first engine I have seen with the camshafts attached to the valve cover and not to the head itself).

Upon inspection of the hydraulic lifters, none of them seemed to be mushy/collapsed (all so stiff that I couldn't depress them by hand) and none of them had any scratches or marks, which makes sense as the camshaft hits the rocker arms first.

All rocker arms also seemed undamaged, with no marks and the "wheel"/contact point was easily turning.

The chain and tensioner seemed in perfect working order. Chain was not too loose or too hard. Thus I don't think it could have been making the noise.

However the intake camshaft had several issues. As seen from the linked images, the camshaft journals and the "bearings" part (well technically this doesn't have seperate bearings, but I'm unsure of what else to call it) are scratched in the valve cover. And the nose of the two lobes of cylinder one (closest to the timing belt) had quite a flat spot:

Video and images: https://photos.app.goo.gl/SmGt2Lz7itSWWQ2x7

1) Do you think that the camshaft could have been making the metallic clicking?

2) I'm thinking about buying a secondhand valve cover with camshafts and all, and then changing the chain/tensioner and re-lubing it all, and 16 new lifters. But do you think that there might been an oil blockage somewhere which lead to this issue?

3) Should I do something else while I have this open?

It's not like the car is worth that much, so i'm also wondering if it is even worth the effort.

Answer 1

Turns out that it was not the camshaft, but more a destroyed con rod bearing on the crankshaft. This however most likely lead to the issues I initially saw at the camshaft...

I really should have started by checking the oil filter, but I guess I just hoped for it to be a simple issue and thus a hydraulic lifter. Anyways this is how the filter looked like, after pressing out all the oil in a vise:

Since I saw that the camshaft didn't have any bearings (this was a new for me), I immediately thought of the crankshaft, and most likely a bad con rod bearing. And I was right.

After pulling the oil pan, I was able to move one of the con rod's side to side with a gentle touch of a finger (see video):

https://photos.app.goo.gl/837rxqRSaQ4B4B477

After removing the rod cap, and the bearing, the crankshaft journals was showing severe scratches

And the bearing was obviously not looking too well. However it is the first time I have experienced the bearing being sqeesed to such an extend that it has gotten wider, kind of funny (See the full album for more images).

Full album: https://photos.app.goo.gl/yh4Z2drydzKZ8D4NA