OK, I am in process of "restoring" my newest project, an '87 300D turbo. Actually getting it to run after being in storage for over 18 months. The problem of a missing cylinderhead is now solved! A used one is being readied with new guides and triple angle valve seats being cut as we speak.
So this morning I yanked the water pump, cleaned the fan and repainted it. I removed the alternator to prep it for a new regulator chip. As I was removing the front antisway bushings (one was loose in its clamp and half of it was chewed up!) I saw that the oil cooler was pretty dirty.
So to clean the cooler fins and an added measure of draining the oil I removed the cooler lines from it and took it out and dunked it in the solvent tank. Admiring it as I blew out the fins w/ compressed air I discovered that the aluminum threads from nipples was GONE, it stayed in the nuts Why did they design the stupid thing using aluminum threads?
Has anyone been down this road b4?
Has anyone heard of a method for removing the stuck aluminum from the threads in the nuts? I tried using a pick awl but its stuck on what looks to be permanently.
How about new nuts? If available, could they be relaced after swaging new fitting on or will that shorten the lines too much to fit?
I see MB has replaced the upper and lower with one size fits all. Darn I wonder if I should have even started this mess! W124 cooler Lines are EXPENSIVE! Like worth more than I paid for the car!

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'95 E320 Wagon my favorite road car. '99 E300D wolf in sheeps body, '87 300D Sportline suspension, '79 300TD w/ 617.952 engine at 367,750 and counting!