I think your problem may be the coolant level sensor.  After many years this
sensor no longer functions correctly and must be replaced.  Part #251919372A
or 251919372, depending on the year.  The current price is less than $5.

Please look a the 4 notes I submitted to the list for an explanation:

Item # Date         Time Recs  Subject
459316 13/10/01 19:13 17 Re: Blinking red light of death
499694 19/05/16 15:28 42 Coolant Level Sensor observation
499700 19/05/16 22:57 88 Re: Coolant Level Sensor observation
499720 19/05/18 13:25 12 Re: Coolant Level Sensor observation

Ed