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Discussion Starter #1
So now that the weather is getting warm again, I am using my AC a bit.

When I first turn it on, I get about 5 minutes of freezing cold air...no complaints about that. Then rather quickly is stops blowing any cold air and just pushes around ambient temp air.

I just replaced the cabin filter with a brand new one but the problem still remains. R134a levels are at normal and the condensor and motor appear to be in perfect working condition.

Car is a 2007 Si Sedan with 110,000 miles.

It's sort of driving me crazy...Any ideas?
 

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So now that the weather is getting warm again, I am using my AC a bit.

When I first turn it on, I get about 5 minutes of freezing cold air...no complaints about that. Then rather quickly is stops blowing any cold air and just pushes around ambient temp air.

I just replaced the cabin filter with a brand new one but the problem still remains. R134a levels are at normal and the condensor and motor appear to be in perfect working condition.

Car is a 2007 Si Sedan with 110,000 miles.

It's sort of driving me crazy...Any ideas?
Do either of the radiator fans turn on when you turn on the A/C? It could be that the condenser is getting too hot, reducing the efficiency of the system to the point that the output starts to warm up. One of the fans should turn on when the A/C is running. Is there anything blocking the grill or radiator? Is it plugged up with dirt, cut grass, etc.?

Once it starts to blow warm air does the compressor continue to run and cycle as usual? Is your engine temperature staying at normal running temp?
 

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Do either of the radiator fans turn on when you turn on the A/C? It could be that the condenser is getting too hot, reducing the efficiency of the system to the point that the output starts to warm up. One of the fans should turn on when the A/C is running. Is there anything blocking the grill or radiator? Is it plugged up with dirt, cut grass, etc.?

Once it starts to blow warm air does the compressor continue to run and cycle as usual? Is your engine temperature staying at normal running temp?
The fans are working and the compressor stays on....the engine temperature appears to remain stable.

The magnetic clutch that activates the compressor might be disengaging. Or, it could be the expansion valve?
The compressor appears to be engaging properly since my pressing of the AC button turns it on and it does blow cold air for a few minutes. If it were the expansion valve would it even be working in the first place?

Are there any sort of fuses or programming in the ECU which could be to blame?
 

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If you keep driving but shut off the AC for a while then turn it back on does it work briefly again?

Once it stops working leave the AC running and check the high and low pressure lines under the hood and see if the smaller line is very warm and the larger diameter line is very cold. Be careful not to touch anything hot or spinning, ha.
 

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Discussion Starter #6
If you keep driving but shut off the AC for a while then turn it back on does it work briefly again?

Once it stops working leave the AC running and check the high and low pressure lines under the hood and see if the smaller line is very warm and the larger diameter line is very cold. Be careful not to touch anything hot or spinning, ha.
Correct...I just did another road test and after 7 minutes, the air no longer was cold. I turned the button on and off but no change.

I checked both lines while the car was at idle but both hoses felt around the same temperature as the underhood ambient temps.

Think it could be the evaporator? I am running low on ideas.
 

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Correct...I just did another road test and after 7 minutes, the air no longer was cold. I turned the button on and off but no change.

I checked both lines while the car was at idle but both hoses felt around the same temperature as the underhood ambient temps.

Think it could be the evaporator? I am running low on ideas.
Both hoses were the same temperature but the compressor was running at the time correct?

I'm not sure what type of expansion valve these systems have, but if it's possible for it to stick open, that could cause the issue. It could also be a compressor issue. If the compressor is running it should be creating flow. The expansion valve should be creating a resistance which causes a pressure difference between the two sides. Either the compressor isn't creating the flow, or the expansion valve isn't causing a pressure difference. Again, this assumes the compressor is running at the time.
 

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Just another thought, though it doesn't really fit well with the fact that the lines are the same temp with the compressor running.

The air blend door in the dash is what changes the temp from hot to cold. If that is getting stuck partially in the warm position (not able to fully go to the cold position) the A/C would seem to work fine when the car is first started. But once the engine starts to heat up the heater would begin causing the air you actually feel to be warmer than it should, even if the A/C was working fine. The A/C wouldn't seem to work again until the next cold start.

Just a quick thought that doesn't really fit with all the details, haha.
 

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I have the exact same car and same problem as the OP - my A/C blows ice cold for as long as 20 minutes before blowing warm air. The next day, A/C blows cold again for a while.

Both the relay and refrigerant have been replaced, but the problem persists. Thanks for any advice!
 

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I would start off by checking voltage at the compressor clutch, see if it's keeping or losing it's 12v supply when the ac dies. If it still has 12v then the clutch coil is bad and the circuit is opening as the coil warms up from being on. There have been a few reports here of coils going bad... with some members reporting that they had to get their compressor replaced to fix their ac... which would also solve a bad clutch coil.

Checking voltage at the coil will tell you if that's the problem or not. If you are handy with electrical you can also jumper the relay and make the compressor turn on manually. If it doesn't turn on then the coil is bad. If you have the old relay you can also take the outer case off of it and manually activate it with your fingers to accomplish the same thing.
 

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I have about 5 minutes a day as well... seems to need to sit a number of hours before the 5 minutes refresh, though I haven't yet checked the amount in the system. Fuzes are definitely not a problem and airflow shouldn't matter as I do mostly highway driving.
 

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I would start off by checking voltage at the compressor clutch, see if it's keeping or losing it's 12v supply when the ac dies. If it still has 12v then the clutch coil is bad and the circuit is opening as the coil warms up from being on. There have been a few reports here of coils going bad... with some members reporting that they had to get their compressor replaced to fix their ac... which would also solve a bad clutch coil.

Checking voltage at the coil will tell you if that's the problem or not. If you are handy with electrical you can also jumper the relay and make the compressor turn on manually. If it doesn't turn on then the coil is bad. If you have the old relay you can also take the outer case off of it and manually activate it with your fingers to accomplish the same thing.
Will need to check these then.
 

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I'm in for some ideas. My AC is acting up like this too. I replaced the relay with no change. AC might work for 5 or 10 minutes at most and it's usually ice cold for that time. In my case, the compressor stops cycling but the fan stays on. After the car sits for a while it might work again, might not. I'm probably taking to somewhere for diagnosis and repair soon because AC repair is out of my league.


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I'm in for some ideas. My AC is acting up like this too. I replaced the relay with no change. AC might work for 5 or 10 minutes at most and it's usually ice cold for that time. In my case, the compressor stops cycling but the fan stays on. After the car sits for a while it might work again, might not. I'm probably taking to somewhere for diagnosis and repair soon because AC repair is out of my league.


Sent from AutoGuide.com Free App
If the fans keep running then it's a good sign the compressor clutch should be engaging. When stopped the fans run whenever the compressor is.

I'm still sticking with clutch coil, or the less common worn clutch that the coil can't engage anymore (too large air gap). to test for sure just test voltage at the coil. Should have 12v when the fans are on.

If you do waterpumps and alternators and are familiar with how snap rings work then you can do the clutch or clutch coil. Don't know if there's room in this car, but on some you can do it without opening the system by unbolting and angling the comp...

I had the same problem with my 07' Si...problem was a bad compressor clutch.
Looks like it's getting common too :( I hope I don't have to do mine, or if I do I hope it dies when I'm not on a long highway trip. Thanks for sharing.
 

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Before you dish out the $$ on a new compressor, check for a bad compressor clutch coil or leak in system (low refrigerant).

To check clutch coil, remove the clutch coil connector and confirm that the voltage to the coil is 12V when the A/C is turned on. If good, then check the resistance of the coil itself. It should be between 3.15 - 3.45 ohms. Outside of this range warrants a new coil.

See http://www.8thcivic.com/forums/mechanical-problems-technical-chat/336745-replace-c-compressor-coil-clutch-without-disconnecting-c-lines.html for a DIY on how to replace clutch coil. It's an inexpensive fix.
 

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Does anyone have an update? My 2008 Civic LX is having the same exact problem. AC only works after a cold start, blows cold but only works for less than 5 minutes. Then it doesn't work until the next cold start.

Thanks!
 
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