Do you have a voltage meter on your cluster? I'd start with getting the alternator and battery checked. IIRC, if there's a low voltage condition, it'll shut off the AC and throw a warning.

Does this car happen to be a 9C1 or 9C3?

 

No voltage meter on cluster and it's a 9C1 (not the "undercover" 9C3)

The only thing that is weird is that this message comes up identically every day at the same time in my routine driving to work and on the way home for the past 3 days. I can even reset the battery when it's hot or cold and it still repeats the same time... just seems to coincidental. I did see some other replies from other forums with a similar problem and they blamed a software update.

 

Take it to a shop or parts store and have the codes read. If you can post the code that's throwing the CEL light, that'll give us a good place to start.

 

2006 LZ9 3.9L Impala Engine Hot A/C Off

Hey i know you posted this over a year ago, did you ever figure out what the problem was??

I had the exact same thing happen to me earlier this summer. I went and got the service manual to check out the problem. Ended up going to a auto parts store, used the OBDII to check it out and a code did come out (dont remember off hand what it was) cleared the code and all has been good since...untill tonight...

Same story you had actually pretty much "engine hot a/c off" fan spinning a million rpm... no check engine light right now. I disconected my battery and tomorrow morning go out and reconnect it to see what happens from there.

Did you end up having to take it to the dealership to have some software reprogramed? i just find this really wierd how i go about 6 months since i had this problem last time and it randomly comes on now. I really hope this is something i can do myself because i NEVER take any of my GMs to my local dealership i think my 6 year old knows more about an engine than their head tech.

Any advise would be great, Thanks!

 

Engine Hot, A/C Off Message

Hey i know you posted this over a year ago, did you ever figure out what the problem was??

I had the exact same thing happen to me earlier this summer. I went and got the service manual to check out the problem. Ended up going to a auto parts store, used the OBDII to check it out and a code did come out (dont remember off hand what it was) cleared the code and all has been good since...untill tonight...

Same story you had actually pretty much "engine hot a/c off" fan spinning a million rpm... no check engine light right now. I disconected my battery and tomorrow morning go out and reconnect it to see what happens from there.

Did you end up having to take it to the dealership to have some software reprogramed? i just find this really wierd how i go about 6 months since i had this problem last time and it randomly comes on now. I really hope this is something i can do myself because i NEVER take any of my GMs to my local dealership i think my 6 year old knows more about an engine than their head tech.

Any advise would be great, Thanks!

Hey Guys,
So it's been quite a while but i am now getting the Engine Hot A/c Off message yet again. It is very wierd how it will not come on for a very long time thing come on randomly. It came on a few days ago for me and i disconected the battery to reset everything. All was well not a few days later i am getting the message again.

Is it the stat thats throwing this message, does it need to be replaced??

Thanks for any advise!

 

I found the problem!

I waited until I had the "engine" light and went to Autozone to have them scan it for me. I forgot the exact code, but basically something about a temperture not being reached (that's why the system puts the fans into overdrive since the car doesn't know if the thermostat is defective or permanently closed causing a dangerous condition for the engine... though I believe there is a coolant bypass also).

Long story short... I replaced the thermostat. I also had intermittent occurances when it would issue would come on once every couple months. I believe the seal was maybe sealing enough after startup and eventually the seal was allowing it to be in an open state before fully warmed up.

Sort of expensive in comparison to your standard thermostat, but found a good deal on Rockauto.com. I removed the old one and sure enough, the rubber seal on the thermostat was totally mangled. So I felt quite a relief. If this is your problem, after replacement, be sure to check coolant level frequently until resevoir level is stable because I found that it took some time for the system to totally burp off all the air after refilling the system. The car has been great since. I hope this helps you out.

Scott

 

code

in case anyone was still wondering the code you're gonna get for this would be p0128 for bad thermostat, coolant temp sensor, low coolant (or leaking), or bad computer. i have this exact same problem, sounds like bad temp sensor or thermostat.

but sounds like i'll be changing the thermostat.

 

in case anyone was still wondering the code you're gonna get for this would be p0128 for bad thermostat, coolant temp sensor, low coolant (or leaking), or bad computer. i have this exact same problem, sounds like bad temp sensor or thermostat.

but sounds like i'll be changing the thermostat.

your temp sensor has failed. well your at it would be a good plan to change the T stat flush and install new coolant.

 

just picked up a new temp sensor last night, gonna have to wait tell the weekend to get it all installed.
Hope all goes well

 

If you have the 3400 motor it takes like 10 minutes, don't recall on the 3800 though...

 

Actually I'm running the 3900 engine (2006 Impala LT 3.9), looks like a tight spot the sensor is on the right up on top below the plastic cover thingy.

 

My bad, thought I was in 7th gen!

 

You have a lot on your mind. You have a free pass today.

 

Any more updates on this? SystemCheck2006 did replacing the sensor work? Or should i just replace the thermostat? Thanks

 

Sorry, server problem, after 3 hours of work (im not a mechanic), i found that replacing the coolant temperature sensor was my exact fix, has been no fluctuation in temp gauge or no codes thrown at me. I hope this helps someone.
I found the sensor at Advanced Auto for $15 order online and set it to be picked up at local store (if convient) and use promo code p20 for 20% off.

 

xFantasyFiendx,

Looks like SystemCheck2006 was able to find a fix. If there’s anything that Customer Service can help with (looking into warranty/recall information, dealership interactions, etc), I’m available.

Best,
Sarah
GM Customer Service

 

im having this same exact problem. i have changed the thermostat and temp sensor. the problem is still there. any suggestions???

 

**update**

After several days the temp gauge just failed on me again, gonna replace the thermostat noticed it seem to trip at same location about 10min into driving when gauge is at one line before halfway mark. From my research it could be a thermostat not fully functioning or the IAT not working.

OBD-II Trouble Code: P0128 Coolant Thermostat (Coolant Temperature Below Thermostat Regulating Temperature)

Sorry, figured after several days of no problems thought the problem was resolved.

 

My temp sensor failed in march this year (2006 Impala LT). The plan was to change the parts with new GM parts (do it right the first time while it's apart.thats how i roll.) GM " T " stat, GM temp sensor,coolant rad cap, flush coolant and install new Dexcool coolant. As of today there has been no problems. Please take note that the after market sensors and electrical parts may or may not have the same parameters as the what came from factory with the car. I personally free that it's not that cost effective to try and cut corners and end up beating my head on the wall thinking what was i thinking when its back for repeat repair!

 

Some aftermarket parts aren't very good, some are. Either familiarize yourself with the brands, or just stick with factory...

 

Thanks. Well I unhooked my battery, it reset the code and my A/C is working again. Something i've recently noticed, i can use my heat no problem, but if i have my AC on, my temperature gauge raises from the C to half way. And yesterday just driving out of my drive, a loud, fast click sound started coming from my car, but if i slide my temperture toward heat it will stop. But after driving with it with cool air going, it did eventually stop, but what could that be?

 

i read somewhere that it could be an actuator, did you have it set to recirculate?

 

Sorry to reincarnate this old thread. I have had the same issue with my 07 3.9 LT as well. I have replaced my temp sensor twice (first with an AutoZone part, and then with AC-Delco part) and still have the same issue.

I am starting to think I do have a problem with my thermostat since it takes almost 15-20 min of driving through my 35 mile commute for the car to warm up to just below the middle of the gauge, and will stay there till it throws "Engine Hot/AC Off".

I will replace my thermostat and get back to this post and provide an update.

 

did they same, the dame thermostat gasket was half there, last time I listen to that mechanic.

 

Gonna swap out the thermostat and spark plugs today since I am close to that 100k mark. After a preliminary inspection of the engine compartment it appears the thermostat housing is on the front lower portion of the engine where the lower radiator hose connects. Can someone confirm this for me, and provide an estimate of how much coolant my system holds (07 3.9).

Thanks guys.

 

Swapped out plugs, not the easiest set of plugs I have changed, but not the most difficult either. As I expected my thermostat looked just like everyone else has described, rubber gasket in the middle was mangled and sticking halfway out. Plugs made a big difference in performance, and on a funny note the plugs in the front were in worse shape than the plugs on the backside. Hmm, maybe the rear bank of cylinders are the ones that shut off in 3cyl mode.

 

I have an 06 3.9L with this same issue. Going to take a look at and probably replace the thermostat and do a coolant flush this weekend. Hopefully it fixes the issue! Thinking about doing plugs soon too but I don't know much about what brand to get. What plugs did you use lotsofspareparts?

 

Delco and ngk are both very good, just make sure you get the iridium plugs, it's designed for them.

 

Thanks for the tip on the plugs!

I replaced the thermostat 2 saturdays ago, cleared the check engine code and have yet to see any more issues. Sure enough the seal on the stat was about half gone. Yay! I can remote start my car again!

Gotta say replacing the part was pretty easy. Will probably end up taking the car into a shop for a full coolant flush and replacement tho. To much of a pain to get all the coolant out of the block.

 

2006 Impala Engine Hot Issue

In reading some of the posts regarding false messages indicating an Engine Hot message (and subsequent Engine Hot/ Turn AC Off) displays, I experienced exactly the same thing with my 2006 3.9 LTZ. One night driving home from work, I got an Engine Hot message and thought "HOLY CRAP!". Shut the car down. I happened to have about a half gallon of Dexcool in the trunk, poured it into the coolant reservoir, started the car and drove a short distance to home. Next morning, checked the coolant level in the reservoir and it nearly full before I started the car. Drove about 2 miles and got another Hot Engine message. Stopped, raised the hood, and put my hand on an engine that was barely warm!!! So I thought...Hmmm, engine is NOT hot
and this is obviously a false message!!

Drove on to work and kept my eye glued to the temperature guage. I did notice that the temperature would swing upward at times but it remained at a higher temp than the usual halfway point between cold and hot.

When I got to work (at AutoZone) I talked with a buddy that was a true SAE certified mechanic. I suspected temperature sensor and he concurred. Bought a new temp sensor, installed it, and everything back to normal since. Note: had to pull off the top 'cover' of the engine as well as a small section of exhaust cross-over pipe the access the sensor. Really was not too bad.

Also noted posts of 'fluttering' or rapid tapping noise when (and ONLY when) changing the temperature settings. Lasts about a minute, etc.
Mine does it too. I know I need to replace the air blend control but have not got around to it yet.

Good to know that these issues are relatively common.