Did I destroy my oil cooler? Will I?

[MNRS6]

So I was going to remove the alternator to replace the voltage regulator. I was trying to pull the oil cooler lines from the filter housing and I could not believe how hard it was to remove? I was twisting the large nut and the pipe started to collapse. I always had a small leak at the filter housing but now it's worse.

Couple questions:
1. What is the exact size of the oil cooler line nuts? (27mm)
2. What is the best tool to take them off? (Just a wrench?)
3. Am I twisting the wrong nut? See picture, I am twisting the large one, but the pipe seems to twist too.

12892

[4.2Crew]

I just completed this same task a month ago... Yes, you want to loosen the large nut. Not sure of the exact size, but I used a small adjustable wrench due to the limited space and geometry. At the time, I recall thinking a O2 sensor-type socket might be useful.

Also, once the alt mounting bolts are removed, you'll likely need to pry the alternator body out of the mounting bracket... The "ears" really seem to pinch and hold it in place. I ground and filed to facilitate the reinstall.

I'm nearby if you need assistance or encouragement.

Good luck!