9th Gen Civic Forum banner
1 - 20 of 23 Posts

·
Registered
Joined
·
122 Posts
Discussion Starter · #1 ·
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?
 

·
Registered
Joined
·
89 Posts
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
 

·
Registered
Joined
·
122 Posts
Discussion Starter · #4 ·
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
 

·
Registered
Joined
·
480 Posts
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.
 
  • Like
Reactions: FG4-ian

·
Registered
Joined
·
122 Posts
Discussion Starter · #6 ·
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.
 

·
Truck? What truck?!
Joined
·
27,924 Posts
Yes, mine does it. In fact, most small engine cars I've owned (with AC) have done something like it.
 

·
Registered
Joined
·
827 Posts
Yea, mine does the same. Even more noticeable since I have damn near solid motor mounts, lol.
 

·
Registered
Joined
·
122 Posts
Discussion Starter · #9 ·
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.
 

·
Registered
Joined
·
480 Posts
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.

 

·
Registered
Joined
·
53 Posts
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
 

·
Registered
Joined
·
122 Posts
Discussion Starter · #13 ·
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
 

·
Registered
Joined
·
38 Posts
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.
 

·
Registered
Joined
·
122 Posts
Discussion Starter · #15 ·
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
 

·
Registered
Joined
·
53 Posts
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
 

·
Registered
Joined
·
122 Posts
Discussion Starter · #17 ·
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?
 

·
Truck? What truck?!
Joined
·
27,924 Posts
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.
 

·
Registered
Joined
·
53 Posts
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
 
1 - 20 of 23 Posts
Top