It's more about current not so much about voltage.
On mine it was the red ones that were blowing out. First try they lasted about 3 weeks without any extra resistors and without checking current, 2nd time with extra resistors that were lying around to bring current down a little bit above replacement LED rating lasted 5 months during colder winter time. 3rd time over the summer after buying resistors to get current to be just under rating they were fine 8 months later when I sold the car.
I also replaced some amber LEDs for indicator without checking current or resistors and they were fine. I guess because they are rarely on and only for short periods of time it does not matter that much if they are a bit over rated current. So I guess yours might be either way over rated current or just bad quality.
Here is the thread I discussed my journey
http://forum.a8parts.co.uk/showthread.php?t=7833