Some data points that may be helpful.
I bought four different electro viscous fan clutches and tried them all out on my truck. This is what I found:
AC Delco 20788261 - Very good lock-up (best of all of the ones I tried), but takes a very long time to disengage, if ever.
Hayden 3222 - Rated for severe duty. Good lock-up, takes between 5 and 40 minutes to disengage.
Four Seasons 46115 - Rated for severe duty. Visually identical to the Hayden in all ways (including QC markings). Likely from the same manufacturing source as Hayden. Disengages within 1 minute (usually less than 30 seconds).
GMB 930-2630 - Leaked internal fluid on first use. No official rating on manufacturer site, but RockAuto and other parts supplier web sites says it is for standard duty. Visual inspection indicates it is not severe duty. It never locked up for me, probably due to the fluid leak.
Due to how quickly the Four Seasons version disengages, it's the one I'm leaving installed. I prefer the higher lock-up of the AC Delco, but the fact that it almost never disengages was unacceptable for my purposes.
I could find no visual differences between the Four Seasons and Hayden clutches. I believe that Four Seasons owns Hayden, so it would make sense that their clutches are identical. But, the two clutches performed differently. All I can guess is that their QC is poor, or I got really unlucky.
Comparison photos are attached.
I bought four different electro viscous fan clutches and tried them all out on my truck. This is what I found:
AC Delco 20788261 - Very good lock-up (best of all of the ones I tried), but takes a very long time to disengage, if ever.
Hayden 3222 - Rated for severe duty. Good lock-up, takes between 5 and 40 minutes to disengage.
Four Seasons 46115 - Rated for severe duty. Visually identical to the Hayden in all ways (including QC markings). Likely from the same manufacturing source as Hayden. Disengages within 1 minute (usually less than 30 seconds).
GMB 930-2630 - Leaked internal fluid on first use. No official rating on manufacturer site, but RockAuto and other parts supplier web sites says it is for standard duty. Visual inspection indicates it is not severe duty. It never locked up for me, probably due to the fluid leak.
Due to how quickly the Four Seasons version disengages, it's the one I'm leaving installed. I prefer the higher lock-up of the AC Delco, but the fact that it almost never disengages was unacceptable for my purposes.
I could find no visual differences between the Four Seasons and Hayden clutches. I believe that Four Seasons owns Hayden, so it would make sense that their clutches are identical. But, the two clutches performed differently. All I can guess is that their QC is poor, or I got really unlucky.
Comparison photos are attached.
