our gd1 aircon coolness turns off after a few hours of driving specially in traffic. usually the coolness goes back after a while but sometimes we have to it or the engine off for a longer time then once we open the aircon the coolness goes back. what seems to be the problem?

 

Sounds like your "freezing" the condenser inside the car. Is there more than normal amounts of water under your car after you shut it off for awhile.

Try running the A/C on outside air setting for awhile or turning it off for awhile and see if it blows cold again when you turn it back on.

If that works you will need to see if your are low on A/C gases or run it on hotter temp settings so the condenser doesn't freeze.

 

Hey b16sir_stock, I had the same problem on a long, hot, 7 hour drive to San Diego. Every hour or so, I pulled over to check for blown fuses, loose wires, etc., but couldn't figure it out. It wasn't until I checked the "cabin filter" that the problem went away.
Apparently, the filter was so filthy, that it was impeding the air flow. All I did was "bang" as much debris out of the filter as I could. That was all I could do "on the road." Anyway, that got me by until I got a new filter.
Give that a try, it is a quick and inexpensive test. With some luck, maybe that is all that is causing your problem.

 

thanks a lot for the much helpful hints.. will try them out and hopefully problems will be resolved.

 

It sure sounds like evaporator icing to me. This will happen when you are slightly low on refrigerant. The system will run too cold and eventually the condensate (moisture out of the air) will will collect and freeze. This prevents the normal air flow from moving through the evaporator and cooling.

The next time this happens to you, leave the fan on full speed and the temperature on full cold. Keep driving and turn off the AC. This will allow warmer air to melt the ice. You should feel it getting colder as the ice melts and after 5 minutes or so it should get warm again because the ice melted away. At that point time turn on the AC again and see if it cools correctly.

You can also stick a thermometer in one of the dash air vents and see what temperature the AC is normally operating at. 40 F. is a good target. Anything cooler than that will lead to icing. You can buy a digital thermometer at Walmart in the housewares department for around $8.00. I have several around but I work on automotive AC systems frequently in the summer.

If this is your problem, the fix is to add a slight bit (2 or 3 ounces) of refrigerant to the system. If you add too much then the system will not cool correctly. The other thing you can do when it happens is simply turn off the AC for a few minutes and keep driving. I have a Blazer that occasionally freezes and I have not bothered to add some R-134. The last time I struck a thermometer in it the temp was running around 37 F.

Good luck.

If you are going to add refrigerant yourself, do not add too much.

 

thanks for the inputs... what is the normal measurement of refrigerant on the guage for refilling up?

 

The answer to that question is "it depends" Here is the problem in answering that question.

Most modern auto AC systems do not specify what these pressures should be. Instead they specify what the total charge by weight of refrigerant should be. There is usually a label under the hood stating the correct charge by weight. When you take your car in for a recharge or top off you (and the tech) can not tell how much is left in the system. So knowing the total charge weight is pretty useless. What they do to get around this is they pump out all of the existing refrigerant and then recharge the system with the correct amount by weight.

Most home people do not have an AC machine to do this so they revert to the old system which was monitoring the pressures.

There are two pressures you can monitor. Low side, which is the input side of the compressor and high side, which is the output side of the compressor. All pressure measurements are usually done with the engine running at idle, with the AC full cold, and the fan running full speed. The biggest thing that affects the pressures is Outside Air Temperature.

What I would do is set it up the gauge(s) and read the pressure on the input (low) side. On an 80 degree day it should read somewhere in the neighborhood of 40 PSI to 45 PSI using R-134 refrigerant. Note: On the high side you never want to exceed 400 PSI. You should never see anywhere near this value except on a very hot day with the engine running at cruise speed.

I would read the pressure on the low side and then add refrigerant to raise the low side about 5 PSI. NO MORE THAN 5 PSI. Then go try it and see if it works for you.

If you add too much refrigerant the system will not work as efficiently and you will probably exceed the high pressure value of 400 PSI on very hot days. Most automotive AC systems have a high pressure sensor that will shut down the compressor if you go over 400 PSI. So, with too much refrigerant in the system when you need the cooling the most on a very hot day is when the compressor cycles itself off and on reducing it's duty cycle.

If you do not have a gauge you can get a single gauge for the low side for around $17.00 from Wally World that has a screw on port for a R-134 can and a trigger. You attach the hose on this device to the low side and read the gauge. Then squeeze the trigger to allow some refrigerant to flow. Let go of the trigger and you can read the low side pressure again. Continue this until you have added how much you want.

Note: The can will get cold as the refrigerant flows out of the can and into the system. The colder the can gets, the slower the refrigerant will flow. You can tell how much refrigerant is left in the can by feeling the bottom and sides of the can for temperature. A completely empty can will feel the same temperature right side up and it does up side down. It usually takes about 5 minutes to empty a completely full can. I do not expect you to use a full 12 oz. can. Walmart (and Sam's Club) is also the cheapest place I know of to buy those 12 oz. cans. I haven't bought any recently because I buy refrigerant in 30 pound containers and that lasts me a few years. It use to be less than $5.00 a can but I heard O'bama's EPA doubled the price of it so I would expect a can to be somewhere in $9.00 range at Walmart.

Good Luck. This is not difficult.

 

thanks for the info... hope i get it right...

 

More like $15/can thanks to the employment prevention agency.