Lexus LS 460

I’m not scientific about it, and I am pretty lazy sometimes, but I do replace radiator caps from time to time for this exact reason. Cheap, easy, and if they fail the results can be pretty bad.

It’s big, solid, quiet, comfortable, luxurious, bland, and indestructible. It used to be a screaming bargain relative to anything comparable, but the price has risen over the years, so now it’s just a good deal. For a screaming bargain in a big luxury sedan you buy a Hyundai Genesis or Equus instead.