# Engine Squeak When AC Is Running



## susan james (Jun 22, 2016)

From inside the cabin, my engine has a noticeable squeak when the AC is turned on & running. Do you think this is a belt or something going wrong with the ac unit?


----------



## Robby (Mar 1, 2013)

susan james said:


> From inside the cabin, my engine has a noticeable squeak when the AC is turned on & running. Do you think this is a belt or something going wrong with the ac unit?


Car is a ...20??........Cruze xx
Model is a ............
Mileage is..............

A bit of info please.

Rob


----------



## susan james (Jun 22, 2016)

Thanks Rob. Car is 2014 2LT with 40,000 miles.


----------



## _MerF_ (Mar 24, 2015)

A belt at 40k miles is certainly possible, in extreme weather environments. It's definitely the easiest and cheapest thing to replace to rule it out. Any chance you could record it and upload to youTube? Preferably a take from inside the cabin and a take looking at the engine with the hood up.


----------



## jblackburn (Apr 14, 2012)

Belt tensioner is relatively common on the 1.4T. Mine chirped until I changed it.


----------



## Robby (Mar 1, 2013)

My first thought too would be a tensioner but this should really be diagnosed directly......kinda tough to give thoughts on a sound without even a recording.

Good luck!
Rob


----------



## susan james (Jun 22, 2016)

Thanks for your replies.
I don't have a smart phone to do a recording. 
What do you estimate tensioner would cost? Is replacement necessary if can put up with the sound?


----------



## jblackburn (Apr 14, 2012)

It should be replaced if squeaking. May be causing wear on other components in the belt path (water pump comes to mind.)

It's actually a relatively cheap part - $30 if my memory serves correctly - and 1/2 hour of labor to replace.


----------



## ChevyGuy (Dec 13, 2014)

There's a couple of known problems that can cause "chirping". (Which sound for all the world like "rotational" but are not.) Loose spark plugs is one. Bad seals and/or a problem with the PCV is another. The latter is easy to test - pull the dipstick while it's squeaking and see if it goes away.


----------



## susan james (Jun 22, 2016)

The chirp does not occur unless I turn on the knob for the blower for ac. It also appears to happen when I turn blower knob on for the heater. Does this narrow it down?


----------



## jblackburn (Apr 14, 2012)

susan james said:


> The chirp does not occur unless I turn on the knob for the blower for ac. It also appears to happen when I turn blower knob on for the heater. Does this narrow it down?


Defrost or floor mode will turn on the A/C compressor.

Just to be clear, is the squeak coming from under the hood of the car and is heard outside the car, or is the squeak coming any time the blower motor inside the car is on (A/C or not?). My blower motor (inside the car) chirps faintly on fan speed 1, and it made me want to punch it last time I was stuck in traffic.


----------



## _MerF_ (Mar 24, 2015)

susan james said:


> The chirp does not occur unless I turn on the knob for the blower for ac. It also appears to happen when I turn blower knob on for the heater. Does this narrow it down?


Possibly, but need clarification. I assume your compressor is always turned on? In other words, is your A/C indicator lit when you turn the blower on? A helpful experiment would be to turn off the compressor (hit the "A/C" button), then turn on your blower and see if the chirp happens. If it doesn't, then it's absolutely a problem with the serpentine belt system (belt, tensioner, or possibly just a bad bearing in one of the pulleys).

The reason this is a valid test: The A/C compressor pulls a considerable load on the engine, so it's possible that with it off there's not enough drag on the belt system to cause the culprit to chirp. Once the compressor clutch engages, it is enough drag to cause the chirp. Unless you are using the Recirc (the "Max A/C" option on some cars...not Cruze) and the blower on max, the compressor is constantly cycling on and off...so the chirp will come and go. If you turn your A/C on max (recirc, full blower fan) so the compressor is constantly engaged, the chirp will probably not go away.


----------



## jblackburn (Apr 14, 2012)

_MerF_ said:


> Possibly, but need clarification. I assume your compressor is always turned on? In other words, is your A/C indicator lit when you turn the blower on? A helpful experiment would be to turn off the compressor (hit the "A/C" button), then turn on your blower and see if the chirp happens. If it doesn't, then it's absolutely a problem with the serpentine belt system (belt, tensioner, or possibly just a bad bearing in one of the pulleys).
> 
> The reason this is a valid test: The A/C compressor pulls a considerable load on the engine, so it's possible that with it off there's not enough drag on the belt system to cause the culprit to chirp. Once the compressor clutch engages, it is enough drag to cause the chirp. Unless you are using the Recirc (the "Max A/C" option on some cars...not Cruze) and the blower on max, the compressor is constantly cycling on and off...so the chirp will come and go. If you turn your A/C on max (recirc, full blower fan) so the compressor is constantly engaged, the chirp will probably not go away.


Yes, except the Cruze never cycles the compressor (unless high side pressure gets too high or refrigerant is low). It's a variable displacement compressor, so it can stay engaged constantly.


----------



## _MerF_ (Mar 24, 2015)

jblackburn said:


> Yes, except the Cruze never cycles the compressor (unless high side pressure gets too high or refrigerant is low). It's a variable displacement compressor, so it can stay engaged constantly.


Oh! Learned something new.


----------



## ChevyGuy (Dec 13, 2014)

And as I recall, the compressor may be on even if the A/C light is off (depending on the mode selected).


----------



## _MerF_ (Mar 24, 2015)

ChevyGuy said:


> And as I recall, the compressor may be on even if the A/C light is off (depending on the mode selected).


That is true of most vehicle, for several years. Namely the defrost/defog (makes no sense blowing humid air on the windshield if you're trying to defog it).


----------

