A/C not working ??

No it's not.

 

but air horns are r134a. which seams super odd to me

 

but anyways u need to check the refridgerant charge and check for a leak

That sucks. Just a little more info, your schrader valve cap should have a seal in it to stop any low rate leaking.

 

if you had a guage set on the lines it would be normal to see the dye on the schrader vlaves. and to see it bubbel a bit right as the hoses are taken off as the residual refridgerant evaporates;)

I dunno....but like 5 min

 

 

actually, what will happen is the unit will short cycle. It will cool all the air in the room really fast and the thermostat will turn the unit off. But then cause all the walls and everything in the room are still hot, it will heat up the air fairly quick again, and the unit will turn back on. This will cycle like that untill the walls and stuff in the room cool down.

 

according to Walmart....18,000 BTU is good for 700-1000 sq ft

 

and if walmart says so, it must be right

Because car AC and and heat loads are ALOT different than building ones. The car is mostly glass, has little to no insulation, and has a ton of infiltration.

 

The compressor is rated at 18,000 btuh, but at what RPM? When you're sitting at idle, it might only 8,000 btuh, while 2500rpmmight be the 18000btuh.

 

I made mine idle at around 1000rpm with the AC on and it works alot better.

 

Something isn't designed right with our HVAC system and I havn't been able to figure it out...I also havn't taken the time to try and figure it out.

 

most car AC systems are in the 3-5 ton range. 1 ton of refrigeration = 12,000 btu.

 

most houses....full houses....have a 1.5-3 ton AC system.

I dunno...it does work eventually though..it just takes a while

If the 134A is low, you have a leak. Take it to an AC shop and they can put Guages on the system and tell you what is wrong. This is normally free just to get a chance at a repair. Usually, it it the condensor (under the dash) not the evaporater (in front of the radiator). The clutch should engage and then disengage right away if the 134A is low. The only way to know is to have it checked with gauges.

^^^ The evaporator (cold) is inside the car. The condensor (hot) is in front of the radiator.

Sorry, i should have proofed the post! All the ac systems i have repaired and i screw up an explanation! Oh Well!!!!!!

If the 134A is low, you have a leak. The clutch should engage and then disengage right away if the 134A is low. The only way to know is to have it checked with gauges.

 

Well, with my car, i evacuated 0.1 pounds of refrigerant (blowing warm air) and my compressor clutch was always engaged with the A/C set on... It wouldn't cycle on and off or anything Put dye in it, saw the leak (see above post), and ordered the new valve which should be in tomorrow..

And PRAY your evaporator isn't leaking, getting to the heater box in a lot of cars is a pain in the arse!

 

Put it this way, at work i just replaced the evaporator on a 1999 Mercedes-Benz S500 (140 Chassis) and the labor time was 36 hours.

well that's an MB. I tried to do a radio in one of those once and we gave up after an hour. We couldn't even figure out where to start without breaking anything.

well that's an MB. I tried to do a radio in one of those once and we gave up after an hour. We couldn't even figure out where to start without breaking anything.

 

Chances are the radio would've came out with radio keys, which MB?

Getting the actual radio out was easy. Euro Din tool. getting the dash apart to do the rest of the work was the issue.

Funny thing happened to me today. Had the A/C on, no problems. Stopped for gas, and when I left again, the A/C wouldn't come on. The HVAC controls are working, and the fan blows air, but the idle never changes and the compressor never engages. Checked the fuse and it's okay. Going to have to crawl around and look at the condenser. If it's anything like my windshield, I guess it will probably need replaced.

took mine in today..my ac blows cold then hot...they told me to turn on the circ .....i started cursing after that.

i have the same issue with the a/c, when i turn it on it blows out nothing but warm air, my mechanic told me that its the radiator compressor. only takes a pin size hole to screw it up. guess its like $75 for a used one. and not very hard to install.

have same thing happening. So what did everyone find to be the cause ?

 

Mine works perfectly with the engine coolant below 90 C. anything above and it is not working. When it is working, it is freezing. When it is not, hot air is coming. I am thinking electrical...since even my engine fans seem to be only working half speed.

Anyone figure out what the problems were to these issues? I am currently having the same troubles, vents blow warm air and A/C clutch never engages, fuses are OK.

you probably have a leak

If there is a hole in the condenser can I just replace it and have a shop recharge the system? I don't know how much compressor oil is left in the compressor/system, and I don't know how a shop determines how much to add...

They'll need to replace the drier... pull the system down (full vacuum), and recharge with oil/freon.

I thought I'd post up on this thread on some issues I've been having with my AC in an attempt to keep the AC conversation in one place.

 

I drive the same route to work every day. Weather is about the only changes the car undergoes between the air conditioning working and it not working. I have linked the air conditioning problems to what seems to be the outside ambient temperature.

 

During highway driving the air conditioning is cold and works well. Occasionally there is a quick and short lived "warm up" in the air coming out of the vents. I think this may be an attempt for the automatic AC controller attempting to maintain the set temperature. This behavior was pretty consistent for temperatures below 90 degrees Farenheit. Just to be sure that it was controller related and not refrigerant related I bought a can of r134a fitted with a pressure gauge and 'topped off' the system. After closing the valve and reading the pressure gauge it was evident I got a little too much refrigerant in the system.

 

The system, running while filling the refrigerant, started to cycle the compressor on and off 1 second at a time. I then bled some of the pressure off a bit until the compressor ran in normal cycle times.

 

The air conditioning system seemed to work normally throughout temperatures up to 90 degrees. Things changed, however, when the temperature outside crept up over 90 degrees. During the same highway driving the air conditioning would "drop out" after running well for 10-15 minutes. The compressor would start the rapid cycling at the same time the air conditioning went into this mode. Air temperatures out of the vents become warm and humid in this mode. Occasionally the AC button can be cycled and I may get lucky for a short time with some cold air. Eventually it goes back to warm and humid.

 

This past week we experienced above normal temps near 100 degrees. I again purged some of the refrigerant to lower the pressure a bit more. I didn't notice a big difference in the behavior of the system. I can still get cold air for around 10-15 minutes of the drive and then the car goes to the quick cycle and warm humid air out the vents.

 

This may be a case of still having too much refrigerant in the system but I also am thinking a possible faulty pressure switch. I consider the switch because at idle the air isn't as cold as when the car is at operating rpm.

 

I apologize for the long winded post but I wanted to throw out some of my experiences that may help others chase their symptoms to a solution. I don't really have a lot to offer on the system since I'm not a HVAC guy. I can say that I don't have a leak in the system although this thread has seemed to prove this as the catch all answer.

Rapid cycling is usually indicitive of LOW system pressure... not high.

do the cooling fans work when the ac is on. should both be on in a high speed mode

I can agree with you on rapid cycling "usually" being from low pressure or refrigerant charge. In my case I do not think I am low being I put a full can of refrigerant in, the gauge red high on the refrigerant level and I had to purge out of the low pressure side a few times to get the AC compressor to even stay on long enough to cool the cabin. Can there be another system component that's affected by the high temps outside that would cause the AC to drop out of operation while running? When the AC drops out it goes into the rapid cycling mode while driving. If its cooler outside I will have no issues.