Bleeding the coolant system 2005 chevy uplander

You might have air lock in heater matrix when bleeding it put heat on full an nd let it get to temperature and bleed it then ..I had a Volvo f12 globetrotter that would overheat coming up Mont blanc at minus 20 outside temperature it was radiater changed perfect after

When the temp. gauge pegs hot what was the real temp of the engine ? Hook up a scan tool that can view live data to see what temp. sensor is reporting to the PCM / ECM , use a Infrared Thermometer to test temp at the engine . GM had instrument cluster gauge problems , bad stepper motors that control gauges . I replaced bunchesof these because people thought vehicle was overheating . 2003 to 2006 gm vehicles .

By removing the water pump obviously alot of water has drained out therefore you need to prime the air out of the complete water system at the radiator. The coolant leaking out is caused by the hot air rising to escape out the coolant bottle the only exit point.With the engine switched off, alocate a bleed screw on the top or on the side of the radiator and open that screw.Then keep pouring water into the coolant bottle until you see air escaping from the bleed screw.Once the air stops releasing and only water then spurts out, close the bleed screw. The system is now 95% primed. Start the engine and let her idle then open the bleed screw again, if only water spurts out for about 5 seconds then the system is completely primed. If there is still air coming out you can rev the engine a bit to circulate the water faster and then the system will bleed quicker(Not forgetting of course to top up the bottle replacing the lost water from bleeding) as soon as there is only water shooting out the bleeder, close the bleeder and top up the bottle to the maximum mark only. If ever you over top beyond the maximum mark just open the bleed screw to let out some water until it drops to the maximum mark and then close.The system is now fully bled. Problem solved.

Was the thermostat changed? I would suggest replacing the thermostat refill the system with new coolant and purge the air out of the system.

If there is no indication of overheating, the check coolant light is probably triggered by a sensor indicating low coolant level. It's also possible that there is air trapped in the cooling system from when the water pump was replaced. Trapped air could cause the sensor to throw the trouble light. Bleed the air from the cooling system and see if the light goes out. You may have to clear the light after bleeding the system.

BLEED AIR OUT COOLANT SYSTEM.WAIT UNTIL ENGINE COOL DOWN.REMOVE COOLANT OVER FLOW PRESSURE CAP.IF YOU HAVE 3.1 OR 3.4 ENGINE OPEN AIR BLEED SCREW ON WATER PUMP BYPASS HOSE.OPEN BLEED SCREW.WATCH COOLANT IN OVER FLOW AS YOU OPEN BLEED SCREW COOLANT WILL DROP IN OVER FLOW JUG. AS IT DROPS CLOSE BLEED SCREW ADD MORE COOLANT IN OVER FLOW JUG DO THIS UNTIL COOLANT LEVEL STAY AT COLD FULL MARK.WHEN DONE TIGHTEN BLEED SCREW DONT OVER TIGHTEN IT OR IT WILL STRIP OUT BREAK.CRANK CAR UP UNTIL THERMOSTAT OPEN THAT WHEN TOP RADIATOR HOSE GET HOT.WATCH COOLANT GAUGE,IF ENGINE TEMPERATURE RISES TURN OFF ENGINE WAIT UNTIL COOL.REMOVE RADIATOR PRESSURE CAP USING A RAG TO KEEP FROM GETTING HANDS SCALED.ADD MORE COOLANT IF NEEDED WHEN ENGINE COOLANT STOP DROPPING IN OVER FLOW JUG AND ENGINE DONT OVER HEAT AIR IS OUT OF COOLANT SYSTEM.

It could be low on coolant,or air in the cooling system,or the coolant low sensor needs cleaning.

the 05 uses the red coolant dexcool which is not compatible with green [antifreeze]if u topped off the nox with green the mixture jells causing all sorts of cooling problems need to flush out system as to bleed screw their isnt one

the thermostat is under the throttle body
remove the air box and the throttle body
remove the top thermostat bolt
the bottom thermostat bolt remove 95% the hole is slotted
replace thr t-stat and reassemble
IMPORTANT
if you have anLX9 engine there will be air bleed scews
if you have an LZ9 it will not have air bleed screws
ok if you have bleed screws open both then fill the rad wait till a STEADY STREAM of coolant is coming out then close bleed screws
start the vehicle put your heater on HOT and VENT AND BLOWER ON HIGH
run vehicle till u get HOT NOT WARM AIR coming out of vents this will insure you have no air in the cooling system

now if you have no bleeders
then fill the rad then install the rad cap
start the engine run engine 2,000-2,500 RPM till the temp. gauge reads about normal about half way
then let the vehicle idle for 3 min
then shut the vehicle off and cool down so the rad cap can be removed
SAFELY
top up coolant
also make sure there is good hot air coming out of the heater if not repeat procedure there is still air in the cooling system
hope you found this helpfull

In my experience with Audis, after any job requiring changing/draining the coolant the car ideally needs to be driven. With the coolant topped up to max drive the car, keep the revs up and shake the car with steering and over bumps where possible. Whatever you do make sure you take at least 2 litres of water/coolant with you, as as soon as the air lock goes, the level drops a lot and quickly. Also keep an eye on the temp gauge and avoid letting it go much over 90 degrees (over 90 on the gauge usually means its well into the hundreds) When you get consistant hot air through the heater, at idle, the level should of settled. If this doesnt work you may have thermostat issues or a blockage. Good luck, let me know how you get on.