Fan seems to constantly run, and A/C performs poorly...2010 SS

[Yellow Camaro]

Can anyone point me in the right direction? The engine fan in my 2010 SS seems to be constantly running. Now if I'm not mistaken, on most cars the fan will turn on automatically if the A/C is on....but seems to run constantly regardless of A/C. It also seems to stay on for sometimes a minute or so after I turn the car. Operating temps seems normal.

The second issue (which may be related), is my A/C has started to really suck. Fans blow great, but the air is kind of lukewarm. If I leave it on full blast, I'll drive for several miles and then all of a suddenly it kicks in perfectly. But the issue is more than it getting warmed up....for example I'll drive for 20-30 minutes, stop for a coffee, and when I get back in the car it's lousy A/C again and then a few miles down the road it is ice cold.

Any ideas? I'm wondering if there's a relay or something that might be effecting both of these issues....

[hush18]

I've been experiencing your second problem. I got my blower motor replaced because ti was squeaking like crazy, however, now my A/C seems to suck compared to before. Not only is the air warm for a while, but my fans also seem to be blowing less than before.

[bruce m]

Have you changed/checked your cabin air filter?

[TheHorse13]

Several things can cause the AC to flip flop between luke warm air and ice cold air. The compressor clutch could be going, the charge in the lines could be just low enough to cause the high/low side value to not open/close, etc. It could even be the relay in the fuse box.

Find a good AC shop if you're out of warranty and let them give it a good look.

[lawdog]

ditto, um Houston, we have something venting out of the side of the ship, I can see it appears to be a white gaseous substance.. Check t out with an AC shop

[cajun1le]

Yellow Camaro,

What is the temperature differential between the outside air and the air coming out of the air vent in recirculate and max cool setting? If it's within 20-30 degrees then its normal. Especially during the summer time heat. The fans can remove only so much heat when you're stationary.

I'll explain things better when I'm off the clock.

[cajun1le]

The engine fan in my 2010 SS seems to be constantly running. Now if I'm not mistaken, on most cars the fan will turn on automatically if the A/C is on....but seems to run constantly regardless of A/C. It also seems to stay on for sometimes a minute or so after I turn the car. Operating temps seems normal.

You are correct that the cooling fans work in conjunction with the a/c system. On the liquid line(high pressure side) there is a three position pressure switch that determines what speed the cooling fans are engaged at. When the call for cooling is low and the vehicle is stationary the fans will be in operating at a low speed (moderate temperatures). As the call for cooling increases, the liquid line pressure will increase. This pressure change is picked up by the pressure switch which kicks the fans into a higher speed to assist in removing the additional latent heat. The same switch also acts as a protection circuit if the system ever encounters a situation where the system pressure is either too low or high.

As for the fans staying on after the a/c system has been disengaged may be tied to engine coolant temperature.

The second issue (which may be related), is my A/C has started to really suck. Fans blow great, but the air is kind of lukewarm. If I leave it on full blast, I'll drive for several miles and then all of a suddenly it kicks in perfectly. But the issue is more than it getting warmed up....for example I'll drive for 20-30 minutes, stop for a coffee, and when I get back in the car it's lousy A/C again and then a few miles down the road it is ice cold.

Ambient temperatures and humidity greatly affects how efficient your a/c systems operates. Whenever you are stationary the system has to rely on the fans to extract the heat from the condenser core. This method is very inefficient and taxes the system quite hard because the system is unable to remove all the latent heat from the cabin. Once you start moving again, more air is allowed to flow past the condenser core which allows the system to remove the latent heat from the cabin (hence it starts cooling again).

It wouldn't hurt to get the system pressures/charge checked given the age of the car. Doing so will reveal if there are any issues at hand. I hope this laymens description on what's going on behind the scenes helps in your understanding on how a HVAC system works. As I stated before, typical temperature differentials should be around 20-30 degrees. I'm not sure what settings you are using but make sure the recirculate option is enabled. This allows the system to cool just the cabin air instead of having to cool hot ambient air.

[bradshaw]

I see a much greater temperature differential of almost 50-55 degrees in both of my GM vehicles. My inside temp gauge regularly reads close to 40-43 with outside temps nearing 100.

[cajun1le]

Originally Posted by bradshaw

I see a much greater temperature differential of almost 50-55 degrees in both of my GM vehicles. My inside temp gauge regularly reads close to 40-43 with outside temps nearing 100.

Indeed, and you will eventually. When I stated the 20-30 degrees temperature differential, that is measured while the vehicle is stationary, vent selector in recirculate with both door windows down. During normal conditions and once the system normalizes the air within the cabin (70-76 degrees). The differential can be greater with discharge temperatures in the 40's. On our cars there is a transducer sitting on the discharge side of the evaporator. Once it senses that the expansion valve is not able to restrict the liquid refrigerant to the core it will interrupt the compressor clutch until temperatures rise just above freezing and then engage the compressor once again.

[Low Saturn]

I had a similar issue on my Suburban a few years ago. Turned out to be the engine coolant temperature sensor. It was sending incorrect temperature readings to the ECU. It was reporting that it was almost overheating, so the fans were constantly running trying to cool the engine and the A/C wasn't working as it should because the ECU thought the engine was overheating, so it was cutting off the A/C compressor. Took less than $20 to fix.

[Bretts]

Originally Posted by Low Saturn

I had a similar issue on my Suburban a few years ago. Turned out to be the engine coolant temperature sensor. It was sending incorrect temperature readings to the ECU. It was reporting that it was almost overheating, so the fans were constantly running trying to cool the engine and the A/C wasn't working as it should because the ECU thought the engine was overheating, so it was cutting off the A/C compressor. Took less than $20 to fix.

thats what my car is doing ever since its tune will check that out

[Bretts]

Originally Posted by Yellow Camaro

Can anyone point me in the right direction? The engine fan in my 2010 SS seems to be constantly running. Now if I'm not mistaken, on most cars the fan will turn on automatically if the A/C is on....but seems to run constantly regardless of A/C. It also seems to stay on for sometimes a minute or so after I turn the car. Operating temps seems normal.

The second issue (which may be related), is my A/C has started to really suck. Fans blow great, but the air is kind of lukewarm. If I leave it on full blast, I'll drive for several miles and then all of a suddenly it kicks in perfectly. But the issue is more than it getting warmed up....for example I'll drive for 20-30 minutes, stop for a coffee, and when I get back in the car it's lousy A/C again and then a few miles down the road it is ice cold.

Any ideas? I'm wondering if there's a relay or something that might be effecting both of these issues....

Yellow Camaro did you ever find the solution?

[Bretts]

Originally Posted by cajun1le

You are correct that the cooling fans work in conjunction with the a/c system. On the liquid line(high pressure side) there is a three position pressure switch that determines what speed the cooling fans are engaged at. When the call for cooling is low and the vehicle is stationary the fans will be in operating at a low speed (moderate temperatures). As the call for cooling increases, the liquid line pressure will increase. This pressure change is picked up by the pressure switch which kicks the fans into a higher speed to assist in removing the additional latent heat. The same switch also acts as a protection circuit if the system ever encounters a situation where the system pressure is either too low or high.

As for the fans staying on after the a/c system has been disengaged may be tied to engine coolant temperature.

Ambient temperatures and humidity greatly affects how efficient your a/c systems operates. Whenever you are stationary the system has to rely on the fans to extract the heat from the condenser core. This method is very inefficient and taxes the system quite hard because the system is unable to remove all the latent heat from the cabin. Once you start moving again, more air is allowed to flow past the condenser core which allows the system to remove the latent heat from the cabin (hence it starts cooling again).

It wouldn't hurt to get the system pressures/charge checked given the age of the car. Doing so will reveal if there are any issues at hand. I hope this laymens description on what's going on behind the scenes helps in your understanding on how a HVAC system works. As I stated before, typical temperature differentials should be around 20-30 degrees. I'm not sure what settings you are using but make sure the recirculate option is enabled. This allows the system to cool just the cabin air instead of having to cool hot ambient air.

Your the bomb Cajun nailed my issue think this should become a sticky great info