I have some Lord Fusor plastic repair epoxy, it’s the best stuff I have found. I found out about it from the bike builders when I cut my Harley fairing and raked it so my headlight wasn’t pointed at the sky when I raked the bike for a 28” front wheel. It had to be the best to hold that plastic together with the way a Harley shakes and vibrates. It never cracked or showed any sign of weakness. My issue I think is finding the leak, it looks like it’s coming from one of the mounting holes and only leaks, barely a drip, when it heats up and the system is under pressure. Whipple said it’s pressurized at 5-8 psi. I’ll know more tomorrow when I pull it off. I forgot to go pick up my 05 hatch glass today so I’m gonna do that tomorrow before I pull the reservoir.
Lord Fusor Plastic Repair Adhesive, Fast, 10.1 Oz. Part #:Fus-142
https://www.amazon.com/dp/B00B3HY53C/ref=cm_sw_r_cp_tai_5r2UEbRT91Y98