So if your car is running rough at idle, maybe check the PCV. I let mine go far too long and this was what it looked like after I finally pulled it out. Turned out to be the easiest fix, you don't even need to remove the cable assembly above it, unbolting it and pushing it back gives enough room to get a spanner onto the PCV itself.
240,000 kms. Didn’t crack anything, it actually came out very easily. it still rattled, but all the cars issues went away straight after changing it.
I can't argue with results. Thanks for sharing your experience! I only posted the link to the other thread so that future readers can avoid that problem if they happen find your thread first. I'm always happy to hear of an older c pushing on!