The key to saving yourself from having to buy an entire t-stat (when you break it by screwing up the threads) is to cut the oil line off. You cut it off by splitting the nut with a cutoff wheel.
The threads are usually damaged by stress, not corrosion. What happens is the oil line gets frozen onto the t-stat by the collar nut being clogged with crud where the oil line enters the back of the nut. When you try to loosen a crudded nut and the nut does not turn on the threads, due to the load placed on the threads by its tightness, the oil line itself spins since it is the path of least resistance. So you've got a loaded nut turning on the aluminum threads and guess what happens- the threads strip.
So you either throw away the t-stat if you really messed up the threads bad, or you use the thread saver fitting.
Porsche 911 & Carrera Oil Circulation - Page 4
To avoid having to repair a perfectly good t-stat (besides it having a faulty temp regulator), you just cut the nut. Or strike the nut & oil line with a rubber mallet or dead blow hammer, hoping to break up the crud that's frozen the nut. The sucky part of the nut cutting is that now you've disabled your oil line and you need a new nut! So then you have to either: 1) re-hose the line to install a new nut (or good a used nut- I save the good ones) or 2) you use one of Elephant's ingenious solutions
Elephant Racing | 30mm Oil Line Tube Nut Replacement Kit | Porsche 911
I would suggest anybody buying a good used t-stat should take the time to put a new regulator in it while you have it removed from the car. That'll save you the hassle of taking it out a year later when the regulator goes kaput. I'm not saying it's a fact that the t-stat regulator craps out regularly. I'm just saying that Murphy's Law occasionally holds true after you've put a lot of work into something.
Murphy's Law: Anything that can go wrong usually will.
Murphy's law - Wikipedia, the free encyclopedia
Years ago my dad (RIP) had a plaque of Murphy's Law on the control panel/"helm" of his houseboat. My dad, as good as a guy there was (i'm biased of course), had more than his fair share of bad luck with mechanical stuff. Especially his boats. Despite him being a great mechanic/wrencher who took good care of his cars & boats, Murphy always picked on him.
I'm glad I got my fill of boats at an early age & I don't want one. Best two days of owning a boat are the day you bought it & the day you sold it!
