Well, I know there's already a topic on a blinking low coolant light, but here's my issue.

I have a 1998 pontiac gp gt. I have replaced almost everything in the cooling system:
coolant level sensor
water pump
thermostat
radiator
radiator hoses

I still need to power flush it from when the dex-cool was in it. (the dex-cool caused a blown head gasket when the previous owner had the car)

Well, the radiator and resevoir are full of coolant (50/50 Peak)

The water pump went out last weekend and the car broke down. I just had the water pump replaced.

I drove the car for a total of 2 days with no issues, no leaks.

yesterday, the low coolant light came on and started blinking, I checked the fluid and it is fine. It came on again today. I'm wondering what the problem is because like I said, the low coolant level sensor that sits underneath the radiator is brand new.

Help.

It sounds like there might still be some air in the coolant system. Try opening the bleeder on top of the coolant elbow. If that doesn't work I would check the sensor again, make sure the wiring isn't damaged or anything. Also to check sure it didn't somehow get gummed up already.

It really sounds like the coolant system wasn't properly bled though.

where is the bleeder at? Thats my major issue..I can't seem to find it.

The bleeder screw is on top of the thermostat housing: How-To - Thermostat Swap

See I have replaced the thermostat recently, coolant was drained completely and thermostat was replaced before I added more coolant...

Well you have to bleed it first. If that doesn't work, I remember somewhere that the low coolant sensor may have to be cleaned or replaced. I think blackarrow knows where that link is. lol

Edit: this might be it:
http://www.grandprix.net/ubb/ultimatebb.php?ubb=get_topic;f=1;t=011427#000001

If the t-stat was replaced recently, I would be willing to bet that the system wasn't bled completely afterward.

Blinking is odd.... Never seen one blink. Either it's on or it's off.

The sensor tells you if the radiator level is low. If there is air in the upper radiator hose the sensor doesn't know it because once the t-stat opens the coolant flows and the radiator stays full.
If the radiator is full and the sensor is still acting up I would say there's a problem with the sensor, or the wiring.

Another way to bleed, and one that I use and believe works better is to put front of car on ramps or on a steep driveway. Remove radiator cap and start car. Now wait and watch air bubbles work their way thru the engine to the open radiator cap. Watch temp gauge and make sure car gets to full temp for a few minutes. This could take 10 minutes total. Fill radiator, replace cap and ensure reservoir is at full mark before shutting off the car.

yeah, 72 is right, that is another way of doin business, but I learned with my L36 Camaro that its so much easier to use the bleeder valve on top of the tstat housing. coolant level sensor might be dirty or have a bad connection. on the camaro, the ECT is above the boss pulley. Not sure where the level sensor is at. MIGHT be one in the same.

Welcome to the board. Enjoy your stay.