So I know you can replace the little white **** on the radiator drain **** and you can also replace the O-Ring, how long do these last?

I guess I'm wondering how it is that on the top end of the system you have a pressurized metal cap (system is under pressure) but the pressure can apparently be held back at just a simple piece of plastic and a rubber O-Ring. So is failure common on these after a few drains (tighten and untighten)? Granted I'm not going to do coolant except every 50,000 but I'm still curious.

Has anyone ever had to replace these due to a leak? Overheating?

 

I don't remember ever seeing a post on this problem. As you say, they don't get used that much so lack of problems is not surprising. Many auto systems depend on long last oring seals.

Orings are not good forever, but do last 10-20 yrs usually, except where heat is high; engine head, oil pump cover, power steering pump, etc.

good luck

 

The bottom of the radiator is cooler than the top. Also, the small diameter means less force (from the same pressure). I imagine the O-ring would wear out from excessive open/closing, like rubbing it rough so it leaks very slowly. Not a real catastrophic failure.