Low Coolant indicator still on.

[STONEBOSS1]

Two months ago I had replaced the low coolant sensor in my 00' regal ls with 168k miles. Thinking that would solve the issue of the low coolant light that had always stayed on prior to replacing it with a new one. Unfortunately it did not. Just a week ago I had installed a new thermostat and new radiator. I used Prestones dex-cool 50/50 to top off the radiator. I am sure the coolant level is sufficient, but that darn light will not disappear. New radiator, new t-stat, new coolant sensor, fresh coolant and still it a low coolant light stays on. I don't get it!!! In addition my temperature gauge at times will show a normal running temperature but will rise to the half way mark. When that occurs I also notice hard shifts when driving. Checked the fluid levels for the transmission and all is fine there. What can I do to rectify these issues and return my vehicle to its normal self.

[jdl]

As far as the coolant level indicator. Terminal B6 at instrument cluster, wire color, yellow wire with black tracer. That wire may be shorted to ground before it reaches the coolant level module. It it is, you need to replace wire. There could be other issues?

[richtazz]

another possibility is you're losing coolant. At 168k, it's highly probable that your lower intake gaskets have failed, as well as the plastic upper intake plenum. Many times, checking the overflow bottle is useless, because when these components fail they don't allow proper cooling system pressure to develop, which is what purges/siphons coolant to and from the bottle. A cooling system pressure tester would show if you have a leak.

If your system holds pressure, but you didn't properly bleed the cooling system after changing the t-stat and radiator, there is most liekely air trapped in the engine. If air is trapped in the cooling system, it can make the radiator appear to be full but when the car is started and the t-stat opens, the air then pushes into the radiator causing both the low coolant light and temp guage issues you're having.

[procaddytech]

The cause of this condition may be due to engine oil contaminating the coolant. Possible sources of oil contamination are internal engine leaks, improper service procedures, or the addition of some types of anti-leak additives to the cooling system. Once in the coolant, the oil leaves deposits on the level sensor creating an insulating film. This film results in a false activation of the coolant level indicator.
Correction
Diagnose low coolant level system operation and check the sensor for oil contamination using the procedure listed below.

Important: No coolant supplements should be used in GM cooling systems, other than what is approved and recommended by GM. The use of "aftermarket" over-the-counter sealing and cooling supplements may affect the operation of the low coolant level sensor. Discoloration of the coolant recovery bottle is normal and does not necessarily indicate that coolant contamination is present.
•Verify that the coolant is at proper level in the radiator and the coolant recovery bottle. If the coolant is low, add proper amount of 50/50 water and DEX-COOL® mixture. If the low coolant light operates properly, diagnose the cooling system for loss of coolant.
•Remove the low coolant level sensor. Refer to Coolant Level Module Replacement in the Engine Cooling sub-section.
•With the key on, the engine off and the coolant level sensor disconnected from the vehicle wiring harness, observe the low coolant light:
• Light is on -- Chassis wiring or instrument cluster concern.
• Light is out -- Proceed to Step 4.
•With the key off, connect the coolant level sensor into the vehicle's wiring harness. Connect a ground wire (1) to the battery negative terminal. Using a sharp probe (3) attached to the ground wire, ground the coolant sensor probe (the brass probe). Make sure a good contact is made. With the key on and the engine off, observe the low coolant light for at least 15 seconds.
• Light is on -- Replace the low coolant sensor and re-check system operation.
• Light is out -- Proceed to Step 5.
•Using a small wire brush or emery cloth, polish the low coolant level sensor probe to remove any film or oxidation. The probe should be a bright brass color when finished. Use Brake Parts Cleaner to flush removed deposits from the low coolant sensor probe. Re-install the low coolant sensor into the vehicle and proceed to Step 6.
•Flush the cooling system and install new DEX-COOL® mixture. If there has not been a recent gasket replacement, locate and repair the source of the engine oil contamination.

[mn_1]

I've done all the repairs to mine, bought a new sensor and cleaned it too. Still came on. I unplugged it.