2001 impala ls temp gauge and ac prob...
#101 Mar 14, 2007
Glad to see I am not alone in this. I have the same trouble with my 2001 Impala 3.4, temp gauge not working, no A/C, fans running and screeching. I am going to try the ground wire fix this evening as I am also having trouble with the fuel guage and aftermarket CD player (FM Transmitter type). All these issues seem to point to a grounding problem and the ground wire seems like a logical place to start. The fuel guage and CD player haven't worked in over a year, but the temp guage started after a really cold snap just before Christmas 2006. It's worked a few times, but mostly doesn't. I had the coolant replaced in Nov about 2 weeks before this problem so it might be the air in the system as well.

Hopefully something will fix this problem. It has gone way past annoying.

Since: Jan 07

Shipman, IL

#102 Mar 19, 2007
Hi, I took my car back into the shop, I printed off the directions from AIB22 (page 2 of this topic) and gave it to the mechanic, he followed the instructions and DID NOT put in a new thermostat. I left the shop everything worked fine, temp gauge worked, fans didn't stay on after shutting the engine off, no god awful noise when I started it. Was fine for a couple of days then it started back up but only for 2 days and now everything is again working just fine, this has been 3-4 weeks ago. It is definitely a cold weather issue. Last week when I would start my car it acted a little strange, was afraid the starter might be going out, took it to the shop and they checked the battery and it was low so they replaced it. I have 160,000 miles on my 2001 and other than a few minor hiccups no major problems (knock on wood). I appreciate the help from this forum.

Savannah, GA

#103 Mar 19, 2007
I replaced my Thermostat. Couldn't understand why, but I tried everything else. It appears to have fixed the problem with the temperature gauge. Not a fun part to get to. The bottom bolt is almost impossible to reach.

The low coolant light came on again, but that was just some crud on the sensor. I have flushed the system twice, but can't get all of the crud out. A little carb cleaner on the sensor fixed it up. Maybe someone with smaller hands could get to it easier, but I have to pull the battery to get to the sensor.

I will write back if the thermostat doesn't hold, but so far so good. I have been messing with this thing off and on for over a year.
Tom Merrimac Ma

Harrisburg, PA

#104 Mar 20, 2007
see my post from March 13th

Hayward, CA

#105 Mar 26, 2007
yea. i believe the a/c stops blowing cold air as soon as the temp gauge is inopperative. I belive it is due to a bad thermostat maybe even coolant temperature sensor. they are very close together, and i know that the c.t.s. isnt that hard to replace. I bet if you change the coolant temperature sensor, change coolant, and replace the thermostat that you should be good!
Cleveland Mike

Akron, OH

#106 Mar 28, 2007
Glad to see I am not alone. I have the same problem on my 2001 3.4L Impala with 63,00 miles. Temp gauge stuck at zero, Fan runs for 3-4 minutes after car is shut off. after reading this forum, I called my mechanic and he said to check the coolant level because sometimes air can get caught in the hoses and prevent coolant from reaching the temp sensor. I checked the coolant level in both the radiator cap and the overflow tank and it was at the correct level however, it did have a slight rust-orange color to it. On 3/27 I took it in to him and he said he tested all the fuses and the thermostat and those were fine. next, he pulled out the dash and tested the wire going to the gauge and it was dead. he replaced this and recalibrated it and everything worked fine for about 75 miles...Until the VERY NEXT DAY when temp gauge went back to zero. so, first thing in the morning on 3/29 I will take it back to him again...I guess I'm back to square one. Also, does anyone know if it is safe to drive a car in this condition?? Because it never overheated before and I have no way of knowing if it is overheating without a temp gauge.

Since: Jan 07

Shipman, IL

#107 Mar 29, 2007
Cleveland Mike, in my post from March 19th you will see that I took my car into the shop along with the helpful hints from this board, it worked fine for a couple days then started acting up for a few more days but then back to normal without taking it back to the shop. So maybe yours will come around too. I did drive my car while this was going on and did not have any additional problems.

Columbus, OH

#108 Mar 29, 2007
I have had a combination of issues with my 2001 Impala LS with the 3.8L. I had the issue of the temp gauge that would go to zero and the fan would run. This occurred even when it was 20 degrees outside. I replaced the thermostat and the gasket (a total of under $8). The gasket was torn and may have been causing the problem. This was about two months ago and it has been fine since (knock on wood). The second issue I had was with the coolant sensor. My low coolant light would go on when the car would warm up. I replaced it for about $57. It worked fine for a few days then get progressively worse until it would be on again once the car would warm up. Took it to the shop. They determined that I bought a bad sensor. Wrong. Theirs did the same thing. Today, I just got back from picking the car up at the dealer. They drained and flushed the radiator (and replaced the sensor for a third time total, first time for the dealer). They felt that sediment in the radiator may be causing the problem. They weren't sure, but for around $200, it is the cheapest option to try. The BCM was clear and no error codes existed. They checked the wiring and it all tested fine. I will post again in a couple of weeks to let everyone know what is going on.
Kimba Meriden CT

Hartford, CT

#109 Mar 30, 2007

United States

#110 Mar 31, 2007
Temp gage and coolant sensor problems:

Oil in cooling system causes repeated "low coolant level" warning. Use fine wire brush or very fine sandpaper to clean pin in sensor spray with brake cleaner dry and re-install.
There is a latching electrical connector just above the battery (I think this part of the cause) attached to the bottom of the brace that goes over the battery. Disconnect, clean, coat with silicone grease, and re-connect.
Hey Joe

Columbus, OH

#111 Apr 6, 2007
joe wrote:
i had the same problem replaced 3 temp sensors which are a pain to do and it finally ended upm being the thermostat which is odd but whatever it works now 10 dollars at autozone and i can finally sleep again so thats what it probably is thanks to jim at best chevy in hingham ma he told me and i didnt believe it good thing i listened good luck
Hey Joe

Columbus, OH

#112 Apr 6, 2007
joe wrote:
i had the same problem replaced 3 temp sensors which are a pain to do and it finally ended upm being the thermostat which is odd but whatever it works now 10 dollars at autozone and i can finally sleep again so thats what it probably is thanks to jim at best chevy in hingham ma he told me and i didnt believe it good thing i listened good luck
Hey Joe Typos in my last post I DIDN'T PURCHASE A SENSOR.... I purchased a THERMOSTAT

Toronto, Canada

#113 Apr 10, 2007
I have 2001 Impala, engine is on. What is the chance of gas cap beeing the problem. My machanic says gas cap is fine. He cleared the code (440 EVAP SYSTEM).The engine light was off till I put in gas,then if came back on. I did turn the gas cap at least five times.

Mckinney, TX

#114 Apr 13, 2007
Hey everyone..
talk about a bad luck.. i just bought my car "impala LS 2001" .. great car to be honest.. but from the second day.. the temperature gage and the ac problem came in (exactly as u guys mentioned).. it seems that it all happened just after i washed the car engine one day after i bought it (also the weather that day was very cold).. anyway i got the car to the dealer (i didn't tell them about the engine wash).. so they agreed to fix the problem. However after few days waiting..i called them and they told me that they fix the A/C.. but the temperature gage is still not working. and i need to get a new cluster (the odometers panel) since they beleive that the temperature gage indicator is the issue. they told me inorder to fix that they need 300 dollars. thats alot of money. can that be the problem.. and how can i know whether they are correct and they didn't made up that diagnosis.. i don't wanna buy a new cluster and end up having the same problem... please help..

Minneapolis, MN

#115 Apr 14, 2007
Deb in Colorado wrote:
2001 Impala...basically the same problem. The fan runs about 5 minutes after the car is stopped and today the temp gauge isn't working. I do have heat, but it doesn't seem as warm. Have not had the check engine light come on. Does anyone have any ideas?
I have the same exact problem did you find out the problem??
Email me please
[email protected]

Mckinney, TX

#116 Apr 14, 2007
OK this is an update.. i really hope it work for you guys..

i did it just by chance and after that everything came up fine.. like magic.. no check engine light.. the temperature gage started working fine.. and everybody lived happy ever after..

well..what i did was: i just unplugged the battery from teh car for few minutes.. then i removed coolant sensor .. jsut to see how it looked like.. then i put it back on.. and put back the battery.. the check engine went away... and in few minutes i noticed the temperature gage went .. and my heart went up with it.. ahhh.. so i didn't have to replace anything.. i didn't have to buy a new odometer pannel as those dealer bastards told me to do..which means little more mmoney in my pocket.. wfew.. anyway.. the ac seems to be working fine.. as i hit the "ac button" i see the car do something.. like the compressor is running or soemthing.. which means it is on.. and working fine.. the heat however is not as hot as i wanted to be.. but i will check it out later... my worries was only on the temperature gage and the ac.. and they both fine now.. so yeah.. try restarting ur car by unpluggnig ur car batteries for few minutes (2 minutes or so) and just try to remove the sensor.. maybe it just needed some adjustments .. i don know.. but it worked at least for me.

Mckinney, TX

#117 Apr 14, 2007

..........i noticed the temperature gage went UP .. and my heart went up with it..........

Mckinney, TX

#118 Apr 15, 2007
who ever try that .. let me know the result

Herod, IL

#119 Apr 16, 2007
Took mine to a GM dealer to have the catalyic converter replaced and they noticed I have a upper and lower intake gasket leaking. I told them to fix it, and while they had it apart to flush out the cooling system and replace the thermostat. Well since then my temp gauge and fans have been working great. Had this work done about a month ago. They said it was probably the thermostat causing the temp gauge not to work, which in turn caused the fans to run longer. Now that it is working like it is suppose to. My fuel mileage has gone back up to where it was suppose to be. With the temp gauge not working correctly, the computer sends more fuel to the intake cause lower fuel mileage. Hope this helps.

Norwalk, CT

#120 Apr 16, 2007
Spent 5 hours on Saturday. Replaced Thermostat (not easy) temp sensor, All hoses and flush and filled radiator. Problem is gone. Old thermostat was clearly defective and broken upon removal.

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