[GM Lifer]

My engine fan ran nonstop during my entire commute this morning, then continued to run for about five minutes after I shut the car off. Gave it a few minutes and then fired up the car again. Same thing--fan ran for five minutes after turning off the car. Engine temp is low, so it's not overheating. Coolant level looks good. Thoughts?

[zaimer]

Have you tried disconnecting the battery for a few minutes? Otherwise my first thought was low coolant - which you said is OK. Second guess is the thermostat is acting up.

[gtfoxy]

Originally Posted by zaimer

Have you tried disconnecting the battery for a few minutes? Otherwise my first thought was low coolant - which you said is OK. Second guess is the thermostat is acting up.

Or the relay.

[GM Lifer]

Originally Posted by zaimer

Have you tried disconnecting the battery for a few minutes? Otherwise my first thought was low coolant - which you said is OK. Second guess is the thermostat is acting up.

No, I didn't try disconnecting the battery. I'm at work with no access to tools. I can see under the hood that the coolant overflow bottle is about half full, which I take to be a good sign.

[TP2SS]

Disconnecting the battery probably won't do anything. There are a few threads here that discuss this issue exactly. My wife's previous '11 CTS did this at one time too (traded it in for a gently used '16 CTS instead of paying for the repair...they gave us full+ trade-in anyway). It's likely the 'stat or the temp sensor.

[GM Lifer]

Originally Posted by TP2SS

Disconnecting the battery probably won't do anything. There are a few threads here that discuss this issue exactly. My wife's previous '11 CTS did this at one time too (traded it in for a gently used '16 CTS instead of paying for the repair...they gave us full+ trade-in anyway). It's likely the 'stat or the temp sensor.

Thanks. I'm kinda thinking along the same lines.

[martelds]

Originally Posted by GM Lifer

My engine fan ran nonstop during my entire commute this morning, then continued to run for about five minutes after I shut the car off. Gave it a few minutes and then fired up the car again. Same thing--fan ran for five minutes after turning off the car. Engine temp is low, so it's not overheating. Coolant level looks good. Thoughts?

I have a 16 2SS, I was driving and ran into the same issue. I also noticed my Rev Matching turned off. If you pull the battery and let it set it will fix it. I have a Blue Tooth ODBC reader all I had to do with clear the code, essentially doing the same thing as disconnecting the battery. One thing I noticed about these cars and my Dads C7 is the get glitches. Most of the time they fix themselves without doing anything. I had my HUD go out, I was kind of freaking. I had a code unrelated to the HUD, but I cleared it and it didn't fix it. I then discounted the battery for 15 minutes and wala, my HUD came back.

[MANNAXMAN]

I've had this happen 2-3 times in the last few months. Every time it has happened, my coolant level was fine and the engine was not running hot. What made each incident even more puzzling is outside temps were low (40s-50s).

[GM Lifer]

Originally Posted by MANNAXMAN

I've had this happen 2-3 times in the last few months. Every time it has happened, my coolant level was fine and the engine was not running hot. What made each incident even more puzzling is outside temps were low (40s-50s).

Same with me. I know I'm in Arizona, but it's only February so it's still cool. Outside temp when I arrived at work was in the 50s. Maybe after a few cycles on and off the problem will go away. In the meantime, I made an appointment to take the car to the shop on Monday. If it fixes itself by then, I'll skip the appointment.

[mrkyleman]

I had this happen when I forgot to plug the MAF back in after installing my CAI. Don't know if you've installed anything new lately?

[2K16SummitSS]

I can promise you it is the thermostat sticking open, causing your car to go into safe mode because it actually reads too low of a temp consistently. Temp gauge drops to 0, fans kick on to 100%, rev match won't work (if you have manual). I went through this multiple times over the course of a year, disconnected and reset, replaced the temp gauge, until I was finally told it was the thermostat causing all of my issues. I have seen this exact problem pop up for many over a few different forums/facebook pages, so I'm guessing our thermostats aren't so great. 10 minute install, cheap and easy fix. Thermostat is right on the top of the engine. If you're under warranty and don't feel comfortable doing it yourself, point the dealer in that direction.

[maldo007]

That happened to me. It was the thermostat and temp sensor. It was a quick fix at the dealer.

[cellsafemode]

Originally Posted by 2K16SummitSS

10 minute install, cheap and easy fix. Thermostat is right on the top of the engine.

I wish it was a simple install for the lgx. They put that stupid thing right in the valley underneath the intake manifold underneath a hard oil/trans return line below the hose level of the radiator.

So you have to take the intake manifold fully off, then fabricate your own wrench most likely to get at the thermostat bolts and bend or remove the return line to take it off, all while you're dumping coolant (or having to partially drain it prior to working).

Pretty sure the designer of that piece of crap has family in the dealership business. It's unnecessarily difficult for something that seems fairly failure prone after 5 years of age.

[CHASLT1]

Never heard mine come on.