Koni Swapped Strut clunking sound

[Claw]

I did a Koni swap to my OEM struts about 2-3 years ago.  They've been great for a while but this spring a clunk developed and I'm having a hard time pinpointing the source of it.

It seems to occur on decompression of the strut.  I've checked my mounting bolts top and bottom and it's all there and tightened to spec.  I thought it might have been the M12 bolt underneath pulling the insert into the body, but that too is tightened and rusted in place.

I took it to a mechanic to check out my suspension and they said everything looks solid, no loose joints, connections.  Also fellow forum member had a look and a test drive and thought that was also strange.  My aluminum Mevotech LCA's from Rock Auto and their bushings are all still good.  I sent an inquiry to Koni and this is what they had to say:

"A clunking noise is very rarely related to the working function or internal compression/rebound damping force of a shocks absorber. That is unless the damper has lost a considerable amount of oil. If the inserts have developed leaks where you are seeing large collections of oil in or around the upper strut mount, or leaking down the strut body, it’s possibly that the clunk is related to the lack of oil inside the shocks. Though if that were the case you would also notice a considerable degrade in the handling/performance of the dampers, not just a clunking noise. Clunks especially in colder weather can become more prominent as the temperature drop and the rubber isolators in mounts, bushings throughout the suspension system become much harder, almost plastic like and less susceptible to movement."

Lastly, I changed from full stiff minus half a turn to full soft minus half a turn, and the clunk seems to be less when the strut extends after I hit a bump.

Thoughts on what it could be?  I know my passenger side strut has a leaky seal so I'll be sending that one in to Koni for warranty replacement, but the clunk is a lot more apparent on the drivers side.

[BoozeRS05]

Seems a couple members are having issues with their Koni struts lately.

I had a full set for 8 years and 80k miles that were removed 3 years ago bc one of my rear springs actually snapped, but the struts were still working great. I’d assume it’s the upper mount before the strut, but maybe Koni quality control is going down hill. Also check your sway bar endlinks and bushings, they’ll clunk very quickly if they’re old or dry

[Claw]

Sure - I'll check the upper mount too.  Also endlinks, the car is almost 18 years old so that's a valid point.

It's odd that if I turn the dial down to full soft the clunk mostly goes away.  Went for a drive up a short 1km road this morning in full stiff and full soft, there's a lot more clunking going on in the full stiff.