Reading just the thread title, are you looking for a self-contained 3mm white/clear flashing LED that matches the blink rate of your existing engine? In other words, something like this where you apply a DC voltage and it blinks by itself (1.5 times/sec in this case):
Or is the matter at hand to find a tiny electronic module with adjustable flash rate that drives a generic non-blinking LED - and it just happens to be a 3mm white/clear LED in this case?
What is the power source?