I am reeeaallly skiddish about this light flashing. I've lost one 
engine because of my overconfidence. I have, however, found two 
occasions where a flashing light was not due to an imminent engine 
failure:

1. Check the wire routing from the water temp sensor. In the 86 it runs 
near the muffler, and in one instance has touched long enough to melt 
the insulation and cause an intermittant short (ie flashing).

2. The second, more common problem, IMHO is trapped air in the 
radiator.

Regards, Vance