Plastic for cooling sucks.

It's funny, I own 13 vehicles none of which sit in a preservation cacoon, all 30-60yrs. old. Not one has blown up a thermostat housing, or started leaking profusely from one. I'm not downing the engineers for this one, I understand the reasons the components are employed using these plastic/composite materials, but one must lower their expectation for longevity out of this stuff.
I've had to replace a coolant housing/manifold on a practically brand new vehicle for a defective/porous condition.
Ford Exploder upper rad tanks with the reservoir parked directly above straddling it, cracking & splitting incognito 'til it gets bad enough to hemmorage all over the place. Yep, gotta love 'em. My '90 Omni has the 1yr only Al-U-minimum/plastic rad with the trans cooler incorporated. Epoxied the tank years back, but guess it's custom all Al, or go with earlier rad & external trans cooler. Maybe there's a Chineseum one out there now, but not when I was lookin'.