A/C ,Very Cool,NOT Cold. Need Possible Causes.

[FlaAveo5]

Ok, my 06 Aveo hatchback, with 28K miles on it, has been hissing INSIDE the cabin for about a month. It started to make the noise and it lasted for 1-3 seconds upon A/C start up a month ago. Now I am up to 10-15 seconds on A/C start up , it is blowing very cool, but not COLD. I checked the refrigerant level and it is full, I forget the number, but it is full, dead center of the low and high of a fully charged A/C unit.I am taking it in to my mech. on Monday. BUT I cant afford a $1,400 A/C repair, and don't want to get screwed. So I want to ask if it could be other things, if his answer is WAY expensive.I told him on the phone today that it is blowing very cool, but not COLD like I like it, and I am use to COLD. That the pressure is correct, and it makes that hissing noise, inside only. That it has been hissing longer and longer, but it blows very cool. just not cold. He says it sounds like an evaporator core problem. I am looking on the internet for the part, and I see it costs from $50-199 new. BUT, can anyone give me ideas of what else it could be besides this evaporator?. I read that hissing INSIDE a car is usually a hole in a vacuum line someplace in the system. I did replace my inside cabin filter about a month ago, and this started a little later. I got a Fram filter with Fabreeze and carbon in the filter, instead of just the plain folded paper one. Could I have pinched a vacuum hose or punctured one? I have replaced it like 4 times, no problem, it comes right out, new one goes right in. But this one is the first one that is not JUST paper. Is it to thick? It went right in and is the right one for the car.So.... what else could it be ...and if it is this evaporator, what kind of price range am I looking at to repair. low-high price. No hissing in the engine compartment, fuses are ok, and no leaking of the refrigerant. The hissing stops after 10-15 seconds now, and it still blows very cool, but I like ice to form on my windows! Hard to do in south Fla. So I have to get it fixed. But any ideas of what it could be, or how much it could be to fix worst case???Does the access. belt need to be tightened or replaced? It is 7 years old and I think it is to loose, but it makes no noises or causes any problems,....unless THIS is the problem???Would that be the issue? I keep asking him to replace it, but he says it is in fine shape and it is an expensive part, plus replacing it is expensive. How expensive could it be? Anyone know that to? HELP!

[milesvinson]

A belt is only about $30 at NAPA. There is no adjustment on the belts. If it is not tight enough, the belt tensioner must be replaced. However, that is probably not problem. Being a former A/C Tech, it sounds like you have a leak in your evaporator coil. A tiny leak will lower the pressure in the coil and prevent the coil temperature from dropping to the lowest available temp. You also try removing/ replacing the filter. You said you installed a different than normal filter. If the filter restricts the air flow too much, the temp will not drop properly. I'd take it to your mechanic and let him double check everything, especially the refrigerant levels.

[FlaAveo5]

Well it is going in on Mon. I just THINK the belt doesn't feel tight, i push on it and it bends down, I always thought it should have only a little bend to it, and this bends down a good inch. But he has seen it like 4 times in a year, and he insists it doesn't need replacement, I just have it set in my mind that it is 7 years old and needs replacement. That is just MY idea. I was thinking about pulling out the new A/C cabin filter, that maybe it is constricting air flow. But why would it be made to fit the car, if it does that. The plain paper ones work,and trap a lot of dirt etc...but this I finally found and it makes the air smell better, but hell if it is the problem, its gone! The refrigerant is at the right level, but of course I am sure he will check that first, or during the search for the issue. Is an evaporator coil the same thing as the evaporator core? The part isn't expensive, but is it a $1,000 repair IF it is that? I know my luck.

[milesvinson]

First, in regards to the belt. If it is 7 years old, I would replace it any way. I have seen and known of sepertine belts to fail/break even thought the appeared fine. When they do fail they usually tear things up like the radiator etc. For example, I was driving a delivery truck at a former job and the belt broke. When it broke the belt wrapped around and ripped loose the transmission lines going into the radiator as well as the lower radiator hose and busted the radiator causing it to have to be towed in. I always believe in doing maintenance PRO-actively rather than post-actively. I would rather change a part at my convenience (timing, affordability) rather than waiting for something to brake /fail and then have to get a tow or roll-back ride and also probably cause more thing to be torn up. I always put on a new serpentine belt when the timing belt is changed. If the old belt still looks in good shape, I put it back for emergency use. I always try to keep one in the vehicle. They are easily and quickly installed. I have installed them before with only a broom handle (no joke). If one of them breaks on you while driving and it does not tear up other things, that used belt can get you back on the road with minimal work and save a tow bill.

[milesvinson]

Secondly, as to the filter. It may not be the problem, but it could be a contributing factor. I know it may be manufactured to fit the opening, but if the cfm going thru it are not enough it can reduce the performance of the A/C. In home heating and A/C systems, most of the sytems are designed with the MINIMUM sized filter usable. That means designed to use with the cheap filters. Many time when people then upgrade to the higher filtration filters like the HEPA or 3M filters the cfms are then reduced below what is needed for the system to run most efficiently.

[milesvinson]

And yes, an evaporator core and an evaporator coil is the same thing. As far as costs to replace goes, I don't know. It depends upon the vehicle and how much the labor rate is. Like most things, Labor is going to be the main cost here. I do know it is usually a major undertaking. As of right now, I need to replace both the heater core (which is located next to the evaporator coil) and the evaporator coil in my 1999 Dodge Dakota. I have all of the parts already and am waiting upon warmer weather to do the repair. I hope you the best of luck and I know what you mean about "your luck"!

[Thymeclock]

I read that hissing INSIDE a car is usually a hole in a vacuum line someplace in the system. I did replace my inside cabin filter about a month ago, and this started a little later. I got a Fram filter with Fabreeze and carbon in the filter, instead of just the plain folded paper one. Could I have pinched a vacuum hose or punctured one?

The hissing is probably a vacuum leak and it may be affecting your A/C in the cabin. Try to find out where the hissing is coming from. It may be unrelated to your changing the filter and mere coincidence that the leak started at that time. The car is old enough to have a deteriorated vacuum line, or something that is causing a vacuum leak.

Either that or you have a snake in there... <LOL>

[milesvinson]

IDK about the 2006, but on the my 2007 Aveo5 I do not think their is anything vacuum driven that deals with A/C systems. According to the GM Service Tech manuals it appears to be completely mechanical and electronic actuated. I know on my older American-made vehicles, the actuator for the mixing door were vacuum driven.

[FlaAveo5]

VERY INTERESTING. I took out the Fram cabin filter and started it up, and I only heard the 'hissing' for 1-2 seconds, and the air is ice cold again! When I took out the filter I noticed there is a permanent dark grey filter with a wire mesh covering, that looks like this Fram filter with the carbon in it, just to the left of the replaceable cabin filter. Does THAT one have carbon in it and other things for filtration? Anyway, I put the filter BACK in this time I THINK the right side up. I THINK I had it in upside down, not sure, but the arrow on it was now pointing up. The hissing still stopped at like 3 seconds. BUT with it totally out, glovebox back in, and radio on, I hear it for 1-2 seconds and it is ICE cold. I put a regular room thermometer, you know glass with that red water/fluid in it, and put it in front of the middle vents and it goes to 58 degrees in 1 min. THATS cold...even for me! Is that about right? Has anyone else done that 'test'? And I get a nice puddle of water under the car, from dehumidify the air, and that has been missing for the past month to.While I still will take it in on Mon. to have it looked over, and maybe to demand to replace that access. belt, IF nothing is wrong with the A/C, other than it needs a cheap replacement filter for some reason. I am doing all this as preventative maintenance to keep it running, that is why I am keeping it, not because I love the speed and grace of the car. Its paid for, it has 28K miles, its still showroom shiny new. So....any opinions on what I just did, and could it have been THAT simple? Because it is ICY cold now, and with the 'normal road noise' and radio on, I probably was hearing the 1-2 second hiss, and ignored it, as normal noise, because it isn't a Lexus stuffed with sound deadening pads or whatever makes high end cars so quite, it is a cheap car, and it took the 10-15 second hissing and lack of COLD air for me to notice it ??? I am just hoping this is the fix, and maybe I was pressing on a vacuum hose of some sort, or a refrigerant hose, but I couldn't find one behind that filter. So...any opinions would still be great, esp. has anyone tested how cold the air is with a thermometer in a min? I got 58 degrees, .....anyone else?

[milesvinson]

58 degrees is about right. Under normal conditions an A/C sytems in vehicles that uses 134a refrigerant should have approx. a 25 - 30 degree temperature drop. This is measured by reading the outside air temp. (or inside cabin temp. if the unit is on recirculate or MAX) and subtracting the temp. reading at the vents. So I'll bet it was about 83 degrees outside when you read the temp. Correct?