My 1998 Bonneville SSE has had the low coolant indicator light come on after driving about 15 minutes. The light will go off and will come on again while driving. The last two days its been "on" and then "off" then "on" again.
The coolant overfill tank is full. No leaks. Temperature stays at 200F.
The car has 72,000 miles.
I wonder if it is the sensor or a real problem?

Thanks

Guess what? COMMON PROBLEM. Although i've never seen one flash, they go out all the time, in every newer GM car. Idk why, they just do. As long as you're sure there is no coolant dissappearing you'll be OK.

check the contacts, the sensor is at the bottom pass side of the rad.

When the car is cold, you need to check the level of coolant in the radiator, too, to make sure. If it is up, then you (like most of us) have a bad sensor. You can try to clean it and re-install it, and when it finally drives you nuts, just unplug it.

Is it another COMMON PROBLEM for a 'Check Oil Level" warning to come on every time my '93 SE is started?....Not immediately, but after the engine has run for about a minute...It then goes away after 2-3 minutes.....The pressure guage shows everything is fine, and the oil level on the dipstick is full....This happens regardless, whether the engine is cold/warm or whether it'* parked on a slope/level ground... :?

Yep -- failed Oil Lever Sender