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Chevy prizm 1999-why temperature gauge floating up and down/
I did it partially:first was changed thermostat and coolant was running thru the radiator but code P0125 was still persist next I was changed ECT sensor and temperature gauge started floating up(to max) and down(to half range).I observed that thermostat is stuck and coolant does not circulate by radiator but when I went Reverse temperature gauge set back to half range.What is the heck?
Re: chevy prizm 1999-why temperature gauge floating up...
Can you tell if your water pump is working, is your water flowing at all can you tell. Here goes some info to help you. http://repairpal.com/OBD-II-Code-P0125
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Trapped air in the coolant might cause that. Is there a coolant air bleed screw on or around the thermostat housing? Crack it open with engine running and see if any air comes out. If no air bleed screw, find a fitting in the top most place on the engine that is in the water passages-the air if any will be at the top. The temperature gauge sender might work: if you loosen a fitting, just crack it open so air could escape, engine running. Once only coolant comes out, tighten the fitting. Don't know what else would cause the gauge to float, unless it was heating unevenly. How hot does it get? Overheating or not? If the engine is running hot, consider having a block test- a simple test, should be inexpensive, where they test for exhaust gases in the coolant, drawing radiator fumes into a container with a special fluid that changes color in the presence of hydrocarbons. And you know what that means: leaking head gasket.
Usually the problem with no heat and overheating is low coolant, thermostat, or a faulty water pump impeller. The radiator may not be full of liquid coolant, or the pump may not be moving the coolant thru the block.
Change the coolant sending unit for the gauge. Usually this is different than the Coolant Temp. Sensor which is for the pcm. Maybe the sending unit is no longer functioning correctly after overheating. Of course, a scanner could show the temperature as recorded by the CTS, or you could use a hand held infrared temperature device to get a better idea of the true temperature.
The most common overlook thing is you got a air pocket, so before you go spend your money turn Heather on full blast, open the radiator cap, car running look for air bubbles, takes patience cause you got to wait for the thermostat to open up, you must refill the coolant really really slow snail pace, some car have a bleeding valve others have two chamber on the overflow bottle,good luck, if that doesn't work change the thermostat first and if that doesn't work I'm afraid you may need to replace water pump. . water pump
YOU NEED BLEED AIR OUT THE COOLING SYSTEM.WAIT TO ENGINE COOL DOWN.YOUR VECHICLE YOU HAVE TO POUR COOLANT IN THE COOLANT OVERFLOW JUG UNTIL COOLANT LEVEL STAY AT THE FULL COLD MARK.THEN START ENGINE LET IT IDLE A FEW MINUTES WATCH COOLANT IN THE OVERFLOW JUG WHEN IT DROPS ADD MORE COOLANT UNTIL COOLANT LEVEL STAY AT FULL COLD MARK.WHEN COOLANT LEVEL STOP DROPPING IN OVERFLOW JUG.SCREW RADIATOR CAP BACK ON OVERFLOW JUG WATCH ENGINE COOLANT TEMPERATURE GAUGE AS COOLANT TEMPERATURE START CLIMBING TURN OFF ENGINE LET IT SET A WHILE KEEP FROM GETTING SCALDED.TAKE LARGE RAG PLACE OVER COOLANT OVERFLOW JUG CAP SLOWLY OPEN RADIATOR CAP A LITTLE AT A TIME UNTIL PRESSURE RELEASE.REMOVE OVER FLOW JUG CAP.ADD MORE COOLANT UNTIL COOLANT LEVEL AT THE FUL COLD MARK ON THE OVERFLOW JUG.THEN SCREW CAP BACK ON THE OVERFLOW JUG.START ENGINE LET IT IDLE AGAIN WATCH ENGINE COOLANT TEMPERATURE GAUGE WHEN TEMPERATURE GAUGE START CLIMBING.TURN OFF ENGINE WAIT A WHILE.CHECK COOLANT LEVEL IN THE OVER FLOW JUG.DO THIS PROCEDURE UNTIL THE COOLANT LEVEL IN THE COOLANT OVERFLOW JUG STOP DROPPING AND STAY AT FULL COLD MARK,WHEN THE TOP RADIATOR HOSE GET HOT THERMOSTAT OPENING AIR IS OUT THE COOLANT SYSTEM. WHEN ENGINE COOLS DOWN.CHECK COOLANT OVERFLOW JUG COOLANT MUST BE IN THE COOLANT OVER FLOW JUG AT THE FULL COLD MARK WHEN ENGINE COLD. DONT .DONT OVERFILL COOLANT OVERFLOW JUG.KEEP COOLANT IN THE OVERFLOW JUG IF YOU LET COOLANT OVERFLOW JUG RUN DRY AIR WILL BE DRAW IN COOLANT SYSTEM CAUSE ENGINE TO OVERHEAT.
YOU NEED BLEED COOLANT SYSTEM.CHECK COOLANT LEVEL IN RADIATOR.ADD MORE DEXCOOL UNTIL COOLANT LEVEL IS CLOSE TO RADIATOR SPOUT.CRANK ENGINE LET IDLE UNTIL TOP RADIATOR HOSE GET HOT.WATCH TEMPERATURE GAUGE.IF TEMPERATURE GAUGE START RISING TO HOT ZONE.TURN OFF ENGINE.LET COOL DOWN.USE LARGE RAG SLOWLY OPEN RADIATOR CAP A LITTLE AT A TIME UNTIL ALL PRESSURE RELIEVED.REMOVE RADIATOR CAP.ADD MORE COOLANT.CRANK CAR AGAIN LET IDLE UNTIL TOP RADIATOR GET HOT.KEEP EYE ON TEMP.GAUGE ALSO.WHEN TEMP.GAUGE STOP CLIMBING.YOUR COOLANT SYSTEM BLED.WHEN DONE LET CAR SET A WHILE CHECK COOLANT LEVEL.ALSO FIRST THING IN THE MORNING CHECK COOLANT LEVEL AGAIN.AND BESURE ADD COOLANT IN THE OVERFLOW JUG TO THE COLD MARK.DONT OVER FILL THE COOLANT RESERVOIR JUG.WORK SAFELY DONT GET SCALDED.
You probably need to bleed the cooling system properly.
Open the cooling system bleeder screws.
Slowly fill the cooling system with a 50/50 coolant mixture until coolant runs freely out of bleeder screws. Close the cooling system bleeder screws Install the coolant pressure cap Start the engine. Run the engine at 2,000 - 2,500 RPM until the engine reaches normal operating temperature. (midway on gauge) Allow the engine to idle for 3 minutes. Shut the engine off. Allow the engine to completely cool. Top off the coolant as necessary.
Run engine again at 2000 - 2500 RPM until the engine reaches normal operating temperature.
Allow engine to idle until cooling fans come on. It should come on with the gauge about 3/4 of the way to red. - if it gets to where is touches the red, shut down immediately.
When the fan comes on, put your hand behind the fan and observe the temperature of the air coming from the fan. It should feel hot. If it is blowing cold air, the coolant is not circulating through the radiator like it should. This could be caused by lots of things including an improper/defective thermostat, corroded water pump impeller, or a blown head gasket.
This problem can be caused by a faulty cooling fan, lack of coolant circulation thru the radiator ( bad water pump, partially closed thermostat) or a partially clogged radiator. Make sure the radiator and condenser in front of the radiator are not full of dirt and clogging the air flow also.
Make sure you get the air out. There may be "high spots" on the engine that you can unscrew to let the air pockets t. Close this small valve when just hot water comes out. Unplug the radiator fan and use jumper leads to test the fan operation. Use a scan tool to check for codes. If you get a scan tool that gives live data, see that the PCM sees the actual temperature of the engine after 5 to 10 minutes of running. It should see the temp. rising to 225 degrees farenheit. Replace engine temperature sensor if the PCM doesn't recognize the proper temperature. You ARE going to compare this to the temperature gauge!!! If all else fails, get the PCM recalibrated or flashed at the dealership.
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