Fan Clutch - Best Brand

[96C280]

I recently tried (emphasize "tried") having my fan clutch replaced. My tech initially installed a new ACM brand clutch I purchased online. After installation, apparently the clutch remained locked up regardless of temperature because I could hear the fan roaring all the time. He ordered a Fichtel-Sachs clutch (costing almost 2x as much). He installed that and it also remained locked up even though the radiator and area around the clutch was cool (confirmed with infrared temp sensor and when engine is cold). We tested this many times. Unbelievably, he ordered another Fichtel-Sachs and upon installation had the same situation. He couldn't believe this and thought maybe there was something weird going on in my car. We installed a clutch from another vehicle that we knew worked and it worked fine on my car, with lockup and disengagement at appropriate temps. Even installed the new clutch on the other car and.....it remained locked up. Anyone have experience with this? Fan clutches are this flaky? So first, is my mechanic and I missing something? Secondly, I'm wondering if I should get a replacement ACM clutch as the Fichtel-Sachs apparently is not having a great track record, either. Is there a qualitative and quantitative difference between the two? One quantitative difference, of course, is that the ACM is almost half the price. My tech is willing to not charge me additional labor for the installation of the next clutch. Obviously, he orders new clutches, he'll keep changing without charging labor. I order, it doesn't work, I'm looking at additional labor charges. With this luck, I'm not going to Vegas anytime soon. Thanks.