Engine hot, air conditioner off
Thread Starter
Safety Car
Joined: Sep 2007
Posts: 3,998
Likes: 487
From: South Florida
Engine hot, air conditioner off
Was coming home from an overnight fishing trip, temp was high 60’s. In the car maybe 3 minutes and get an alert for hot engine, air conditioner off. Look over at coolant temps and it’s reading 0 on the gauge, check the electric part and reads XXX*. I immediately checked my oil temps and they were only at 147* so I figured it was just the sensor. Pulled off 95 and got to a safe place to pop the hood and see if I smell any coolant or engines hot. Intake manifold was barely warm definitely wasn’t hot. Disconnected the battery and now it’s working. Checked the coolant sensor itself for signs of cracking or a disconnection and everything looks good. I did a search and didn’t find an answer to this. Is it possible the car did this due to it being cold out and these dry sumps take forever to get oil temps up. Could that car have just freaked out itself from being too cold? Either way I’ll be having redline Motorsports check it out when I get my car there for an oil change.
Racer
Joined: Feb 2021
Posts: 290
Likes: 64
From: Lyon, France
2025 C6 of the Year Finalist - Modified
Have something like this each two years.
Try to clean sensor electric connection with something like that https://www.bicyclehero.com/fr/maxim...B#googtrans(fr)
Unplug
Spray
Replug
Unplug
Let it dry for 5 mn
Replug
Try to clean sensor electric connection with something like that https://www.bicyclehero.com/fr/maxim...B#googtrans(fr)
Unplug
Spray
Replug
Unplug
Let it dry for 5 mn
Replug
Last edited by Blackship; Jan 21, 2023 at 04:45 PM.
Race Director
Joined: Mar 2011
Posts: 13,262
Likes: 3,150
From: SW Florida
2021 C6 of the Year Finalist - Modified
I had the exact same thing happen to my 2011 GS.
1. Engine Hot .. A/C turned off message on the DIC
2. Coolant temp gauge reading 100 (lowest number on the gauge) even when the engine is up to operating temp.
3. Coolant temp on the DIC reading XXX
_____________________________________
I replaced the coolant temp sensor, but after a couple of days, the same thing happened again, so that was no fix.
And a couple of days after that, my electrical connector to the radiator fan melted and of course, the engine actually got hot since the fan was not running anymore. I am thinking that it all had to do with the fan connector burning and not making a good connection (until the connector completely burned up).
Anyway, I removed the connector and hard-wired the fan (now eliminating the connector) ... and I don't have the problem anymore.
Problem fixed ...
1. Engine Hot .. A/C turned off message on the DIC
2. Coolant temp gauge reading 100 (lowest number on the gauge) even when the engine is up to operating temp.
3. Coolant temp on the DIC reading XXX
_____________________________________
I replaced the coolant temp sensor, but after a couple of days, the same thing happened again, so that was no fix.
And a couple of days after that, my electrical connector to the radiator fan melted and of course, the engine actually got hot since the fan was not running anymore. I am thinking that it all had to do with the fan connector burning and not making a good connection (until the connector completely burned up).
Anyway, I removed the connector and hard-wired the fan (now eliminating the connector) ... and I don't have the problem anymore.
Problem fixed ...
Race Director
Joined: Mar 2011
Posts: 13,262
Likes: 3,150
From: SW Florida
2021 C6 of the Year Finalist - Modified
BTW ... My bet is that when you check the fault codes on your car, you will have a P0116 code ... even though the 'check engine' light never came on.
Moderator, Tech Contributor
Joined: Sep 2013
Posts: 15,410
Likes: 3,964
From: Cape Coral, Florida
Was coming home from an overnight fishing trip, temp was high 60’s. In the car maybe 3 minutes and get an alert for hot engine, air conditioner off. Look over at coolant temps and it’s reading 0 on the gauge, check the electric part and reads XXX*. I immediately checked my oil temps and they were only at 147* so I figured it was just the sensor. Pulled off 95 and got to a safe place to pop the hood and see if I smell any coolant or engines hot. Intake manifold was barely warm definitely wasn’t hot. Disconnected the battery and now it’s working. Checked the coolant sensor itself for signs of cracking or a disconnection and everything looks good. I did a search and didn’t find an answer to this. Is it possible the car did this due to it being cold out and these dry sumps take forever to get oil temps up. Could that car have just freaked out itself from being too cold? Either way I’ll be having redline Motorsports check it out when I get my car there for an oil change.
Race Director
Joined: Mar 2011
Posts: 13,262
Likes: 3,150
From: SW Florida
2021 C6 of the Year Finalist - Modified
And actually snap the 2 pieces of the connector apart and look to see if there is any damage to the metal contacts where the two pieces snap together.
BTW ... Has any 'tuner' said they increased your radiator fan speeds sometime in the past ?
Set the max fan speed above 90% and it will sooner or later burn up the connector.
BTW ... Has any 'tuner' said they increased your radiator fan speeds sometime in the past ?
Set the max fan speed above 90% and it will sooner or later burn up the connector.
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From: Cape Coral, Florida
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Race Director
Joined: Mar 2011
Posts: 13,262
Likes: 3,150
From: SW Florida
2021 C6 of the Year Finalist - Modified
Oh ... and a big thumbs up for 'C5 Diag' (Rob).
Since all the wiring and grounds in my very low miles 2011 GS are in perfect condition, I was going to order a brand new E38 ECM (computer) for my car because of this problem, but 'C5 Diag' talked me out of pissing away money for a new computer !
I am pretty good at turning wrenches, but I just wish I had 25% of the electrical diagnostic expertise Rob has !
Since all the wiring and grounds in my very low miles 2011 GS are in perfect condition, I was going to order a brand new E38 ECM (computer) for my car because of this problem, but 'C5 Diag' talked me out of pissing away money for a new computer !
I am pretty good at turning wrenches, but I just wish I had 25% of the electrical diagnostic expertise Rob has !
Thread Starter
Safety Car
Joined: Sep 2007
Posts: 3,998
Likes: 487
From: South Florida
And actually snap the 2 pieces of the connector apart and look to see if there is any damage to the metal contacts where the two pieces snap together.
BTW ... Has any 'tuner' said they increased your radiator fan speeds sometime in the past ?
Set the max fan speed above 90% and it will sooner or later burn up the connector.
BTW ... Has any 'tuner' said they increased your radiator fan speeds sometime in the past ?
Set the max fan speed above 90% and it will sooner or later burn up the connector.
Car is tuned by Howard Tanner at Redline. I asked him about the fans before he tuned the car and if I believe he said he doesn’t mess with them much due to burning out the fans, this was also over a year ago so don’t quote me on that. My car will still get up to 220* in bumper to bumper in south Florida traffic which makes me thing they are still on the stock settings or weren’t moved too much. He did say the LS engines run better hot (coolant temps/oil temps) which I also agree with because my old C5 on the dyno did its best numbers after 6 pulls when the oil was in the low 200’s-220’s. I’ll check the connector tomorrow as well as the cooking fan connector tomorrow. The car also has a 160 or 180 stat also.
Race Director
Joined: Mar 2011
Posts: 13,262
Likes: 3,150
From: SW Florida
2021 C6 of the Year Finalist - Modified
My supercharged GS also has a Redline Motorsports tune.
I don't think Howard was the one that increased my fan speeds ... This was done a long time ago when Chuck 'CoW' was tuning on my car (and also had me install a 160 degree thermostat).
After re-wiring the fan, I have now set my fan speeds back to OEM speed settings using my HP Tuners.
I don't think Howard was the one that increased my fan speeds ... This was done a long time ago when Chuck 'CoW' was tuning on my car (and also had me install a 160 degree thermostat).
After re-wiring the fan, I have now set my fan speeds back to OEM speed settings using my HP Tuners.
Safety Car
Joined: Aug 2017
Posts: 4,912
Likes: 2,319
From: Etobicoke (Toronto) Ontario
Once the thermostat opens to its max, airflow becomes the determining factor. That and obstructions to the airflow like crud blocking the AC condenser or rad. So if you are stuck in traffic the fan programming becomes the determining factor, not the thermostat set point. And there’s enough evidence to suggest increasing the fan duty cycle shortens the connector’s life,
Thread Starter
Safety Car
Joined: Sep 2007
Posts: 3,998
Likes: 487
From: South Florida
My supercharged GS also has a Redline Motorsports tune.
I don't think Howard was the one that increased my fan speeds ... This was done a long time ago when Chuck 'CoW' was tuning on my car (and also had me install a 160 degree thermostat).
After re-wiring the fan, I have now set my fan speeds back to OEM speed settings using my HP Tuners.
I don't think Howard was the one that increased my fan speeds ... This was done a long time ago when Chuck 'CoW' was tuning on my car (and also had me install a 160 degree thermostat).
After re-wiring the fan, I have now set my fan speeds back to OEM speed settings using my HP Tuners.
Advanced
Joined: Jan 2021
Posts: 72
Likes: 51
From: Martinsburg, WV
Oh ... and a big thumbs up for 'C5 Diag' (Rob).
Since all the wiring and grounds in my very low miles 2011 GS are in perfect condition, I was going to order a brand new E38 ECM (computer) for my car because of this problem, but 'C5 Diag' talked me out of pissing away money for a new computer !
I am pretty good at turning wrenches, but I just wish I had 25% of the electrical diagnostic expertise Rob has !
Since all the wiring and grounds in my very low miles 2011 GS are in perfect condition, I was going to order a brand new E38 ECM (computer) for my car because of this problem, but 'C5 Diag' talked me out of pissing away money for a new computer !
I am pretty good at turning wrenches, but I just wish I had 25% of the electrical diagnostic expertise Rob has !
Instructor
Joined: Mar 2017
Posts: 220
Likes: 21
From: SAN DIEGO CALIFORNIA
Thread Starter
Safety Car
Joined: Sep 2007
Posts: 3,998
Likes: 487
From: South Florida
This is when mine did it, and I noticed whenever it gets cold down here (below 70*0, the coolant temps will jump around higher than normal at freeway speeds (up to 212 at 50-80mph, then get cooler when the car slows down and sits in traffic which is the opposite of what it does normally. Normally I spike to 212 or so in bumper to bumper traffic in the dead of summer, and will get down to 189 on the highway. I knew something was off because the oil temps never rose with the coolant temps, which it always does naturally.
Instructor
Joined: Mar 2017
Posts: 220
Likes: 21
From: SAN DIEGO CALIFORNIA
This is when mine did it, and I noticed whenever it gets cold down here (below 70*0, the coolant temps will jump around higher than normal at freeway speeds (up to 212 at 50-80mph, then get cooler when the car slows down and sits in traffic which is the opposite of what it does normally. Normally I spike to 212 or so in bumper to bumper traffic in the dead of summer, and will get down to 189 on the highway. I knew something was off because the oil temps never rose with the coolant temps, which it always does naturally.
I think the car might want to see at least 150F or 160F or so water temp before you get to a 45mph+ steady speed.