Cracked Plastic Tank on Radiator

[Gill]

Hey guys, I have a few questions, if anyone has the time. Thanks in advance

My car broke down the other day while I was on the road far from home.

The first sign of trouble was steam coming from the engine compartment. The cause of the steam turned out to be a crack in the plastic top of the radiator, in a location underneath the air intake. It looked like the seam, but it wasn't.

I took out the radiator and the radiator guy replaced the plastic top. He charged me $180.

I am pretty concerned about this, because I prefer a reliable car. Don't want a car that leaves me stranded. What if I had been driving the in-laws to the airport?

I have cooked an engine like this, years ago. That happened on the expressway and the steam blew away, I never saw it. The cause was a pinhole in one of the hoses. So this radiator leak was a pretty dangerous situation for my car.

Does anyone know what causes this? I have read that it can be coolant, either mixed coolant or none at all. The car generally has Nulon, which should be ok.

I have also read that it can just be age, and that you should replace the radiator every few years, but this doesn't seem to be necessary with magnas, so what is happening? Do all 380s need a new radiator, or just mine?

My car has 350k, mainly shortish trips, so it could be mileage based, I suppose.

It sounds like I could have just loosened the radiator cap and just kept on driving, since the leak was at the top. I didn't want to risk it at the time.