The Buick 3800 had a tube like that on top, it would crack from thermal stresses and piss out hot coolant. There was an aluminum aftermarket replacement like you describe but it was Dorman and a cheap fix. Buick also addressed the problem in later versions. I miss that engine.
I used to own a W124 series Benz (bought used for 5% of sticker price, I ain’t no fauntelroy). Nearly everything on it was redundant or excessively skookum.
When systems that weren’t as rugged started going down, like the vacuum controllers for doors or the 4matic computer etc, the car still worked safely with reduced convenience. A few minor design flaws like the wiring harness but that’s it. Room to work under the hood, too.
It was built in '93 when the engineers still ran the company.
Current main driver is the super reliable '03 CRV.
