I cut through the "nut" on the last oil cooler hose refurb and still lost some threads. In my case, I judged that I still had enough threads to reuse my cooler.

Next time ( I still need to do my 300SD) I think I will try to make 2 cuts 180 degrees apart and pry the nut halves off the oil cooler.

Too late to help you . I would not be afraid to buy a used cooler from a boneyard for $20-$30. U-pull it here has them for that kind of money. I think the odds are in your favor at that kind of price - but I wouldn't pay $100 for a used cooler unless you can already see the threads.

__________________
80 300SD (129k mi) 82 240D stick (193k mi)77 240D auto - stick to be (153k mi) 85 380SL (145k mi) 89 BMW 535i 82 Diesel Rabbit Pickup (374k mi) 91 Jetta IDI Diesel (155k mi) 81 VW Rabbit Convertible Diesel 70 Triumph Spitfire Mk III (63kmi)66 Triumph TR4a IRS (90k mi)67 Ford F-100 (??)