Plastic for cooling sucks.

I worked on medium and heavy trucks (class 7&8) for 40 years at a municipal garage. International and Freightliner had plastic coolant tanks. I might have replaced one International in that time. Freightliner's lasted about 3 years and would get pin holes in them. The Peterbilts had metal tanks and never leaked. The plastic/aluminum radiators are a toss up. Some last and some don't. FYI a Freightliner radiator 5 years ago was $2300.
Most if not all of the heavy trucks I've been driving for the last 10 years or more all have plastic reservoir tanks. The old Freightliner that I drove for 5 years needed a new rad about 2 years ago, dunno what it cost the company, but I don't think they were happy. Their problem, not mine, keeping a 20 year old truck on the road.