Faulty Coolant Bypass Valve

[pabille]

Does anyone know why a coolant bypass valve (otherwise known as the heater control valve) will fail? I replaced a faulty one about four months ago and now the replacement is leaking. I know they tend to leak but did I just get a bum replacement or could there be another reason?

 

[dynamite196]

your heating system could be clogged. Have you ever flushed the radiator?

 

[pabille]

I do a coolant system flush once a year around April. The first leaking valve appeared a couple of months after my last flush. Now I have this one leaking four months after the last one.