[oplix]

This is mostly noticeable when at a stop. Part of the AC system in my 2015 civic will cycle on and off every 10 seconds making a sort of vibrating noise.

Is it normal for the system to cycle like this at idle?

 

[RayBans2111]

For reference,

I live in Texas, and when i'm at a stop with the A/C on, my RPMS hover around 850-1000, and I can hear my A/C kick on every 10-20 seconds. It's more of a humming noise and not so much a vibration though.

/R

 

[X83]

I'd check the AC pressures to see if they're normal then maybe suspect a belt tensioner or engine mount issue.

 

[oplix]

I don’t think that engine mount would make it intermittent especially if the RPMs are rock stable at idle.

Feel like it could be one of the other things though

 

[ampm1678]

I think its pretty normal, I've been using my A/C more frequently the past couple weeks since I started driving my civic again after having it sit for 4-5 weeks and my car cycles on and off between the loud vibration/humming noise when at a stop. It's also noticeable from the outside of the car as well when I put the car in park to unload from the trunk with the A/C left running.

 

[oplix]

I think it also might go away after the car warms up a bit. So not even sure wtf it is. Maybe it is normal. I can't imagine it's like that off the lot though.

 

[scottyrocks]

Yes, mine does it. In fact, most small engine cars I've owned (with AC) have done something like it.

 

[15WhiteSi]

Yea, mine does the same. Even more noticeable since I have damn near solid motor mounts, lol.

 

[oplix]

Interesting. Seems like a common problem. Wonder what causes it.

sounds like it could even warrant a recall if there is a mechanical part which is failing prior to the claimed service intervals.

 

[X83]

Maybe you could track the issue down with a mechanic's stethoscope to see where the noise is actually coming from and isolate the source of the suspected problem. It might be from inside the AC lines pulsing or belt tensioner vibration or a collapsed engine mount. Honda has quite a few service bulletins with problems in these areas.

 

[0dyfamily]

All three of our Civics (2012 LX, 2013 EX, 2014 LX) do that. We've had 115°F heat, multiple weeks over 100°F.

Our 2011 LX Accord (2.4L I4) does the same, but to a lesser extent.

Our three V6-powered Honda-Acuras ... hardly notice it (bigger driveline?).

OF

 

[bfaided1984]

Mine does this during the 100+ temps. The stiffer motor mounts make this even more noticeable.

 

[oplix]

All three of our Civics (2012 LX, 2013 EX, 2014 LX) do that. We've had 115°F heat, multiple weeks over 100°F.

Our 2011 LX Accord (2.4L I4) does the same, but to a lesser extent.

Our three V6-powered Honda-Acuras ... hardly notice it (bigger driveline?).

OF

Ya it could be that the engine is bogging due to the percentage of power being sapped from the AC which causes a rough idle

 

[othesneako]

This isn't a "problem" so to speak its just the nature of the AC system. What you're hearing is the compressor cycling on and off. The hotter it is outside the more the compressor has to work to keep the AC pushing cold air.

Think about the noise that a normal air compressor makes (for air tools, for example), they are pretty loud but only when they are actively compressing air to fill the tank. The AC compressor in your car is smaller than a compressor in a full size air compressor AND it is compressing a refrigerant gas which is more dense than air, which makes it it harder to compress / less compressible, and in turn requires more work.

Its most likely functioning how its supposed to, BUT if it is exceptionally loud (and its already noticeably loud when its working just fine, mind you) it might need some lube on the clutch/pulley, or maybe it is over/underfilled with coolant. Like mentioned above check the AC system pressure and see what you get if its really howling, but if the air is still coming out at a consistently cold temp then its probably fine.

I have pretty stiff motor mounts and mine is extremely noticeable at a stop (very loud and you can FEEL the increased vibrations when it kicks in), but the compressor is fine, system @ correct pressure, etc.

 

[oplix]

This isn't a "problem" so to speak its just the nature of the AC system. What you're hearing is the compressor cycling on and off. The hotter it is outside the more the compressor has to work to keep the AC pushing cold air.

Think about the noise that a normal air compressor makes (for air tools, for example), they are pretty loud but only when they are actively compressing air to fill the tank. The AC compressor in your car is smaller than a compressor in a full size air compressor AND it is compressing a refrigerant gas which is more dense than air, which makes it it harder to compress / less compressible, and in turn requires more work.

Its most likely functioning how its supposed to, BUT if it is exceptionally loud (and its already noticeably loud when its working just fine, mind you) it might need some lube on the clutch/pulley, or maybe it is over/underfilled with coolant. Like mentioned above check the AC system pressure and see what you get if its really howling, but if the air is still coming out at a consistently cold temp then its probably fine.

I have pretty stiff motor mounts and mine is extremely noticeable at a stop (very loud and you can FEEL the increased vibrations when it kicks in), but the compressor is fine, system @ correct pressure, etc.

It’s not the sound level. There is a vibration

 

[0dyfamily]

We just had the AC on the 2013 EX serviced last year. Even at factory loaded refrigerant mass, it still vibrates, though now the vibration amplitude is noticeably less than the our other two Civics.

All three are running at near-identical pressures, but the 2013 definitely shoots colder air out of the vents at all temperatures.

Given the 2012 LX is ten years old, it's due for an HVAC service. I'll have my local tech recover the R134a (he can keep it), replace the Schrader valves myself, evacuate and charge to mass myself.

That should get it back to "factory cold" out of the vents and reduce vibration like on the 2013.

OF

 

[oplix]

We just had the AC on the 2013 EX serviced last year. Even at factory loaded refrigerant mass, it still vibrates, though now the vibration amplitude is noticeably less than the our other two Civics.

All three are running at near-identical pressures, but the 2013 definitely shoots colder air out of the vents at all temperatures.

Given the 2012 LX is ten years old, it's due for an HVAC service. I'll have my local tech recover the R134a (he can keep it), replace the Schrader valves myself, evacuate and charge to mass myself.

That should get it back to "factory cold" out of the vents and reduce vibration like on the 2013.

OF

How much did you pay for the service? Honda dealer I assume?

 

[scottyrocks]

It’s not the sound level. There is a vibration

Again, normal. When my AC cycles on, the engine idle does an on-and-off rough and smooth, similar to what you had previously mentioned.

 

[oplix]

Again, normal. When my AC cycles on, the engine idle does an on-and-off rough and smooth, similar to what you had previously mentioned.

Just very curious what exactly is causing this. Certainly not all small engine cars are like this (I imagine)

 

[0dyfamily]

How much did you pay for the service? Honda dealer I assume?

I think it was just $80, but this was before refrigerant prices went way, way up this year (as in more than doubled). I'd guess it would now cost me easily over $100 with current prices.

Local tech with a late model Robinair Recovery / Vac / Charge machine (not a Honda dealer). He's taken care of at least four of our vehicles in the last couple years.

OF