Help With Car A/C ....

[marc3039]

Let me start by saying I'm the most car illiterate person out there ...

That said, my car's A/C stopped blowing cold air a few days ago ... it is still blowing, it's just that the air is warm (not hot).

What are the chances it could just need more freon ?

It is giving off sort of a weird smell everytime I crank it on to test it.

Any motorheads have any advice ?

Should I take it in to get looked at, or could I solve the problem ?

Thanks.

 

[accuratehorn]

There are several reasons why the system will blow, but no cold air. The most common is low or out of refrigerant, but this is not the only reason.
There is a low pressure switch in the system which will cut off your compressor if the system is real low, or completely out of refrigerant. So you may be turning on the switch, but the compressor is not functioning.
If you have a slow leak, adding some refrigerant may get you some cold air until it leaks out again. If you have a fast leak, it won't last very long. If you have a car made after about 1994 or 95, you don't have freon (R12)., you have R134A in the system, which you can buy yourself. But you won't know if you are putting exactly the correct amount in the system if you just add some. You might put too little or too much. The systems have started using less and less in them as the efficiency and desire to help with global warming has increased.
If you put too much in the system will work inefficiently and it is hard on the compressor.
Then there is the possibility you are not even low on refrigerant, but something else is wrong-compressor failure, compressor clutch failure (A/C fuse blows, indicating the clutch is drawing too much current, getting old) , A/C relay or wiring problem, or A/C switch (or heaven forbid-climate control system problem, which is computer controlled) all can go out at some point.
As a shop, if the system is low, and we can't see an obvious leak, we evacuate and recharge with the right amount of refrigerant and add a flourescent leak detecting A/C oil to the system. This dye shows up eventually under a black light. If the leak takes two years to leak out, you won't worry about fixing the leak, but if it leaks out in two months you will want to fix it, most likely.

 

[utexas_61]

This happened to me, and I was hoping it was just the lack of freon. So I got it refilled. A month later, warm air again. son of a ***** cost $600 to fix.

 

[marc3039]

NOT what I wanted to hear ...

Did you refill your fluid yourself ?

 

[capnamerca]

Personally, when this happened to me, it was a busted compressor - had a leak. Would blow cold for ~2 months. Quoted $800 to fix, cause apparently it's hard to get to. I haven't had it fixed yet since I bought a new car, but my uncle (ex mechanic) said he can fix it. Still a pisser.

 

[marc3039]

**** !!!

 

[marc3039]

Can anyone explain the smell coming from the vents ?

 

[Horneius_Maximus]

Damn Car A/C's I am in the same situation. And what accuratehorn said is bang on the money. Exactly what my mechanic told me yesterday. I am dreading the monetary damage on this one!

accuratehorn, do you work at Midas on El Camino and Charleston in palo alto? Just kidding, good info though

 

[spidey69]

Vent smell could be unrelated. Moisture condenses in the vent ducts under your dash and can mold causing a foul odor.

Car repair stores have an anti-bacterial/fungal spray that you can spray into the recirc and outside air intakes to clean this up. I have had to do this with one car and it does work.

A/C. You already have some good advice. Hopefully a slow leak that you can recharge yourself. You may have to jumper the Low Pressure cutout switch to actually charge the system. An Expert will tell you should monitor both sides (Low Pressure) and High Pressure sides and they would be correct; however, more often than not you can get away with the a $20 recharge kit. It might take more than one can to get going. I kept my jeep AC running for 4 years by charging every summer.

 

[accuratehorn]

Yes, the odor, if it is a musty smell, is most likely leaves and oak tree droppings along with dust and moisture that collects in the fins of the evaporator core. Newer model cars come with "cabin A/C filters" or some call them "pollen filters," like your home A/C unit, in order to trap this junk before it gets to the evaporator.
The debris can be bad for allergies, and it can smell bad. It can also clog the evaporator so much that you cooling capacity is reduced, sometimes significantly, and it can contribute to the tubes in the evaporator corroding enough to leak-which could be where your refrigerant has gone.
If the clogging is minor, one of those sprays can kill the mold and help with the odors, but if the housing is really clogged up, the only real fix is removal of the evaporator core, and either cleaning it with a strong cleaning solution, or replacing it if it is leaking.

 

[TyWebb]

On the same note, my air conditioner will blow cold air out the vents, but sometimes it wont blow any air out the vents, almost like there is something stuck that prevents the air from coming out of the vents. You can hear the air trying to get out, but it won't for a few minutes. Is this a coil problem?

 

[accuratehorn]

The A/C vent problem is likely nothing to do with the parts of the system that carry the refrigerant or with the compressor.
It is probably a problem with the vent control-there are flaps that open and close to direct the air to the windshield, under the dash, or through the center vents. These flaps can get warped with the Texas heat over the years, and get sticky. Or more likely, there is a vacuum system which pulls the flaps open, and it may have a leak somewhere. There is a tank in most cars under the hood just for this system to hold the vacuum so the system will always have enough to operate, and a hose or the tank could have a leak.
This is just a typical system, and some models may operate electronically, and be computer controlled.
The fix could be fairly cheap if it is just a vacuum leak under the hood, or could be expensive if the flap unit itself had to be removed from under the dash, or if some electronic control is bad.
Also, on the original car, there are inexpensive things that go wrong. We have found a loose ground wire for the compressor in one car, and everything worked fine after tightening the connection. But it could also be a compressor that came apart internally, sending pieces of metal throughout the rest of the system, and cost a lot of money.
One car had wires chewed apart by a nesting field mouse under the right inner fender panel. Ants can get in the relays and short them out. We have found filed mouse nests in the cage of the blower fan motor under the dash.
It isn't always a leak of refrigerant that can be fixed by a can of R134A.

 

[BigWill]

******* mice.

 

[frogballs]

About that smell...

Automakers are downsizing components under the hood as much as possible these days. This includes making the evaporator in your A/C system smaller. To make the evaporator more efficient, they added more fins and packed them closer together This has made the evaporator more prone to trap moisture that contributes to the growth of bacteria and fungi.

To fix this, if you have a Ford you can buy a Purge Module which cycles the blower motor to dry out the evaporator for a period of time after the engine is shut off. The module will work for most Ford cars, but it requires a special harness depending on the type of electrical system used in the air conditioning in the particular car. You can call your local Ford dealer to see if one is available for your car.

General Motors has a similar system called Electronic Evaporator Dryer. The EED turns the blower motor on and off in 10 second bursts where the Ford Purge Module runs it continuously. This will save your car's battery. There is also a temperature sensor that will turn the blower motor off when the ambient temperature is low enough that the possibility of microorganism growth is at it's lowest. The good thing with the GM product is that it is not based on what type of electrical system is used; it can be used on any General Motors product without any modifications. GM claims it pushes out two to three times more moisture from the evaporator than the Ford product, but that is an unsubstantiated claim, and like most things GM motors says, cannot be trusted.

If you're like me and own a Honda Accord, neither of these products would do me any good. But then again, I don't have a problem with A/C stench, so I don't have to worry about it. My last car was also a Honda Accord, and I never had any problems with A/C stink either. Therefore, I've never checked to see if Honda has any such component for their cars.

If you don't want to buy equipment like that, you can keep a can of Lysol in the car and spray it in the air intake about once a week. There are other chemical treatments, like Frigi-Fresh. It isn't a long term solution, but it lasts longer than Lysol. Another option is Clean N' Coat, a two-part chemical that embeds an antibacterial in an acrylic coating that sticks to the evaporator. It comes in a spray can that you can spray on the evaporator and offers protection for about three years.

 

[MrPhlegm]

Or instead of forking over big bucks to Ford or GM for their fancy schmancy blowdryer battery runner downers you could turn off the AC and just run the blower a few minutes before you shut down the engine for the day.

 

[accuratehorn]

Frigi-Fresh is a good product, but it is mainly sold to shops. You put the system on outside air instead of recirculate and spray it on the air entry ports at the base of the windshield. I just did this on my wife's car.
One more possibility that could account for your odor and reduced cooling-a clogged drain hose. Is the water still dripping out under the car when the A/C is on? If not, there may be a pool of water in the housing for the evaporator, and the drain hose needs cleaning or blowing out.