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AC... How cold?

5K views 22 replies 10 participants last post by  gilbertguy 
#1 ·
So, how cold would you say your AC is coming out of your vents? I'm the fourth owner with 255,000 miles and have had the car for a year so I have no idea what has been done to the AC system on this car. I have a small dial gauge that slips into the vent to tell me the air temp. Here is where mine is at:

With outside temps around 105-110 and dial set to 61 AUTO the temp coming out of the vents on city streets and at lights is 70F. When running down the freeway at 65MPH I am getting 60F. All I have is a dummy gauge for putting in a can of freon, it is on the high side of the green range. Was in the red so I actually let some freon out, I need to get a real set of gauges to see what the high side looks like also.
 
#2 ·
do you know if your windshield has been replaced or its original honda?

I think the problem with aftermarket windshields is that they dont have as good heat rejection as the original honda ones, so in a sunny day, the air from the a/c gets heated from the sun coming out the vents before reaching you.
 
#3 ·
Just had it replaced 2 months ago, had the problem with the old one also and have no idea if it was original or not. I've had plenty of cars and even with after market windshields they would get colder then this. Just trying to get a feel for what the system should be putting out of the vents, 70F while running around town isn't what I would call cold AC.
 
#4 ·
Driving at urban speeds at high ambient temperatures, I would think that the A/C condenser cooling fan would be on. The fact that the A/C outlet air temperature is significantly cooler at highway speeds may indicate that the A/C condenser cooling fan isn't working correctly. If the A/C system cannot cool the refrigerant sufficiently, the result could be less heat removed from the cabin air (i.e., warmer A/C outlet air temperatures).
 
#5 ·
Good lead on the condensor fan, may want to check into that.

I'll try to remember to put a thermometer in my vent and measure how cold it is just while sitting idling in my driveway. That should be worst case as far as condensor air flow goes. I can test on all three cars too, so that should give a good indication of where your temps fall.
 
#7 ·
Condensor fan is running like crazy and took a garden hose to it when I bought the car last year. Eli, that would be great to compare all 3 of your cars with the thermometer, let us know what kind of reading you get. I did a check on my other 3 vehicles (non-hybrid) and just sitting in the drive with the AC cranking it is coming out of the vents around 50F degrees, on the freeway it drops to around 40F.

My fear is that the "black death" is clogging my condensor, thus the high reading on the low pressure side. What is Black Death? Anyone know if Honda compressors use teflon rings?

So, if anyone else out there has a thermometer that they can take a reading at the vents I'd still love to know if 60-70 is normal or if my car does have issues.
 
#8 ·
Will do. The only variable will be ambient temps. It's only around 80 here right now.
 
#9 ·
From my experience and knowledge.....AC on........50F out the vents is normal.
HTH
Willie
 
#11 · (Edited)
Ok, here we go.

Climate control set to Auto, dial at 60 degrees, recircle on in all three tests. Just idling in the driveway.

#1:
Car Ambient = 92ºF
Outside Ambient = 84ºF
After about 3 minutes, the A/C began cycling off/on and maintaining the output air temp between ~50 and 52ºF.

#2:
Car Ambient = 87ºF
Outside Ambient = 84ºF
After about 4-5 minutes, the A/C began cycling off/on, maintaining a temperature between 52 and 54ºF.

#3
Car Ambient = 98ºF
Outside Ambient = 84ºF
After about 3 minutes, the A/C began cycling off/on, maintaining a temperature between 50 and 52ºF.

It seems #2's A/C is slightly weaker than the other two cars. Interesting. Not that I ever use it.. lol.
 
#12 ·
I did not read all the black death article, but why not service the AC first by sucking it down and filling with the correct amount of freon? I would have expected Eli to have temps in the mid 40s, but I'm no expert. I guess having 3 alike pretty much tells his numbers are probably right. Just a little moisture in a system will kill its effectiveness. Vacuum will remove it by boiling it out (the opposite of radiator cap providing pressure so coolant boils at higher temp). I think that would be the place to start. What I have done in the past when replacing a component is take the car to someone who can legally remove the freon, then I have taken the car apart, replacing each O ring after flushing the part with brake cleaner and air. Then I take it back for pumping and filling. Has worked well for me. I guess you would see black death if you did that.
 
#13 ·
Thanks Eli, I will try mine in the morning when the temp will be the same as yours. Having all 3 within a few degrees of each other says that is probably where it is supose to be. I am betting if you were crusing on the freeway you'd get temps closer to 40. Will let you know what I find in the morning.

@ Kenny - Because I have no idea what this guy did to the AC system before I got the car I think I may need to do like you said and vacuum it down and start from scratch.

Now I wonder if all that rust across the top of my condensor would have anything to do with how it performs..... nah. haha
 
#14 ·
Put a meat thermometer into the dash vents.

AC only has to pulldown 20 degrees from ambient, to be working as designed.

When you do get a recharge/check make sure they add fluorescent dye to the AC system so the next guy can trace leaks.
 
#15 ·
Okay here are my numbers with controls set to 60 AUTO at idle:

Car Ambient = 96ºF (was in the hot garage overnight)
Outside Ambient = 86ºF
After about 3 minutes, the vent output air temp between ~63 and 64ºF.
After about 10 minutes the vent output air temp was 60, the A/C never began cycling off/on but ran constantly.

I'd say I have a freon issue of some kind? I think I'm going to have to vacuum down the whole system like Kenny recommended and start from scratch. I'm also looking for a reasonable set of AC R134 gauges that I can acurately read both the high and low side to get an idea of what is actually happening with the system.

Thanks Eli for checking the temps, helps me to know my system has issues and it just isn't me thinking that is the way these cars run since I bought it used.
 
#17 ·
Sort of along the line of a/c performance is how hot these cars can get in sunshine with windows up--(we have very sneaky rain showers).
Anyone ever fitted vent shades allowing your windows to be cracked a bit but excluding rain?
 
#18 ·
Yes, I have vent visors along with seveal other INSIGHTERS. There are NO exact fit type made for teh Gen 1..

Willie
 
#19 ·
Thought I would give an update on this thread. Got a set of automotive AC gauges this winter so here is what I found wrong with my car. When I put the gauges on the car the freon pressure was crazy high, like 85 PSI on the low side. I actually had to release freon (I mean recapture it) from the system to bring the pressures back down to where it was supose to be. Now that I've properly set the freon pressures with the right amount of freon in the system the tempurates coming out of the vents gets down to 48F when the compressor turns off and begins the normal on/off cycle process.

I never dreamed that there was to much freon in the system but this makes sense, originally when I would turn on the AC it was like throwing out a parachute. Now that it is set correctly I can feel a slight power dip when the compressor turns on but nothing like before. That AC compressor was creating screaming high pressure with to much freon in the system and it was really bogging down the engine trying to do it.

This was also stealing battery charge from the IMA battery because I was using so much assist to constantly help the bogged down engine. I'm actually not fearing this summer now that my AC is working correctly.
 
#20 ·
Weird that you mention that, one of my Insight's the only one I checked when connecting it to an automotive a/c gauge with the compressor off and not turning it on for at least a day was off the chart, 100+ PSI. The A/C seemed to work fine with it but I never really have used it outside of a roadtrip to Nevada. Even in 85+ degree weather here I have it off to save MPGs so I couldn't tell you. Of course sitting pressure isn't what you should look at. You need to measure pressure with the compressor running and at the specified RPM as per the vehicle manufacturer. The data is in the service manual and Honda specifies that measurements happen with doors open, nobody in the cabin, recirc on, max fan, 60 degrees, at 1500RPM, and some other stuff and it gives a PT chart and instructions to follow it. I've never touched it or really measured it for this car because I haven't had a reason to but for other cars that have had A/C leaks, I've always gotten 40 degrees colder from vent air the car pulling fresh air from outside than what the ambient temperature was. If you need colder than ambient you should turn recirculation on, especially if it's 110 degrees ambient, you'll never get to 70 degrees or lower inside with pretty much any car if you're in the sun with that if you aren't on recirculation.

For what it's worth, this doesn't have a normal Honda compressor in it. It's a 12,700BTU rotary compressor made specifically for the Honda Insight by Sanden. I'm not sure if Sanden made any compressors for other Hondas or not but I'm pretty sure they aren't rotary compressors as all other compressors that I've seen in cars have been piston compressors.
 
#21 ·
Yep, when you turn off the compressor the pressure will equalize between the high and low side, thus your 100psi. Most AC systems on the low side should be around 35-45 psi while running under conditions you stated, it all depends on the outside tempurature when testing happens. I have a chart for R134a that cross reference temp for pressures.
 
#22 ·
I'm curious about the behavior of the compressor that you observed. I'm pretty certain that others in this forum have stated that with our climate control as opposed to A/C system, the compressor runs continuously when the climate control is on regardless of the temperature setting. Temperature is controlled only by mixing in air heated by the engine coolant. So to get the maximum fuel efficiency in hot weather, one should set the temperature to 60º and turn the climate control off and on to control the temperature manually and thus avoid the wasteful mixing of heated and cooled air.

Running the compressor continuously doesn't make sense to me, especially in a car designed for maximum fuel efficiency. But you and Eli describe the compressor cycling on and off as I would expect. So is the temperature controlled by cycling the compressor or mixing in heated air?
 
#23 ·
I'm curious about the behavior of the compressor that you observed. I'm pretty certain that others in this forum have stated that with our climate control as opposed to A/C system, the compressor runs continuously when the climate control is on regardless of the temperature setting. Temperature is controlled only by mixing in air heated by the engine coolant.

(As I drive down the road I watch my thermometer i have in my dash vent, it is pretty easy to see when it hits about 48F I can feel the compressor turn off on the engine, thus the temp begins to slowly rise. Once it hits around 52-55ish the compressor turns on. This is with the temp setting at 61 so it doesn't blast me out.

Also you are correct about the air mixing in the sense that when you turn the Auto temp knob and raise the degree number it will begin to open the hot coolant shut off valve to allow it to warm the air and achieve the higher temp you desire. I need to set it to 60 which will fully close the shut off valve and then disconnect the control rod, that way even if I set it to a higher number no hot coolant enters the HVAC.)


So to get the maximum fuel efficiency in hot weather, one should set the temperature to 60º and turn the climate control off and on to control the temperature manually and thus avoid the wasteful mixing of heated and cooled air. (See answer above)

Running the compressor continuously doesn't make sense to me, especially in a car designed for maximum fuel efficiency. But you and Eli describe the compressor cycling on and off as I would expect. So is the temperature controlled by cycling the compressor or mixing in heated air?
Hope my answers above make sense, take your out on the Freeway and set temp to 61, recerc, fan speed on 1 or 2. If you have a temp gauge that you can put in your dash vents do that, I bet you will see your compressor cycle On/Off as you drive at a steady continous speed down the road. Some times city is hard to see because of constant starting/stopping, especially if you use ECON Auto stop.
 
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