| Subject: | | Re: Recharging R-134a |
| Date: | | May 05, 2004 at 07:00:34 |
| Posted by: | | Fordadicted on via: or 64.83.11.161 |
| In Reply to: | | The message posted by jaason on May 05, 2004 at 06:25:18: |
Stop and take a good look at your A/C system. Look at the front of the compressor. Is there any oily residue around there? If so, this is an indication the compressor shaft seal is bad. If the compressor is over 5 years old, 3 years for Fords (FX-15, FS-10) You may as well get a new one. Always buy new if you can afford it . Good compressors are Delphi , Apcoair , Airpro , Sanden , Seltic , Nippondenso, Visteon .... if you must . DONT use 4 seasons , murray , everco , factory air .
Now, the accumulator/dryer. You don't have to replace if its recently been replaced , or the system has not been open before , but remember, an accumulator can hold up to 40% of the system oil charge , so you may add too much oil to the total amount the system needs , and have high pressures . Most are not terribly expensive, so go ahead and replace it. Also, accumulator/dryers absorb moisture from the air. Don't keep it open any longer than necessary to service it if you decide to re-use it . If its 5 years old ,dont even think of re-using it . If you're vehicle has a thermostatic fan clutch on it. Examine it. The fan pulls air over the condenser and should operate at maximum efficiency. Fan clutches are a very common problem on rear wheel drive vehicles. If the fan clutch has any oily residue on it, (front or back), it will not operate at full capacity. If your not sure, replace it. A bad fan clutch will cause high pressure and compressor failure. Buy a good fan clutch , no cheapies here . IF you have an electric radiator cooling fan , make sure its working . A fan not working will burn up a AC quickly . Now look at the entire hose assembly. Look for oily residue around where the hose connects to the metal lines. This is another sign of leaking. Replace or repair if needed. If its only leaking at the spring clamp , replace the o-rings there , and lube them good with Nylog oil . If everything looks good, your ready.
If your compressor failed , then you must Remove the system components and flush the oil and trash out of each one. It is almost imperative you have compressed air to blow the flush out of the system. DO NOT flush the compressor. Turn it up and drain it. (if not replacing) Sometimes no oil comes out of it. You can also pour about 2 oz's of system oil into the suction port and manually turn the compressor. Keep turning and the oil will come out the discharge port. This will help flush out what ever is in the compressor.
Do a good job on the evaporator flush. Gotta have compressed air to do it right. (You don't have to remove )
Replace the condensor , it is much too hard to clean , and you cannot get all the trash out of it . It has too many little areas for trash to hide and mess up a new system.
Replace the orafice tube / line . Keep the new accumulator/dryer closed up until last minute install . Install it last .
Replace all O-rings with the new ones. Coat them with system oil or Ny-log lube. Pour 4 oz's of oil down the compressor suction port.
1 oz in condenser---, 2 oz's in evaporator---, accumulator gets 2 or 3 oz's.
Total system oil charges vary. Check to see how many oz your holds . Close the system up and start pulling a vacuum asap. Once you have a good vacuum, turn the compressor by hand a full 12 to 14 revolutions. This will clear any oil on top of the compressor pistons. Continue pulling down for about 40 minutes. Turn the vacuum pump off and watch the gauges. The system should hold vacuum. If it doesn't, check your gauge connections and then all the system fittings.
CHARGING,
After pulling a good vacuum , open the 134 can , purge the guage lines , and fill her up until it wont take anymore . Turn on car and put AC on high . Add refrig until you have the recommended amount .
If the compressors clutch dont engage , check cycle switch . If that dont cure it then check for power to it , and compressor .
Stick a thermometer in the vent. Set RPM at 1500 to 2000. Watch gauges, Wait for compressor to cycle. Dash Fan on low speed will let it cycle (Assuming all radiator fan problems have been corrected) When it does, make note of the low side pressure. Compressor should cycle out around, say 22 psi. If it cycles at 25 psi, look at the vent temp. High side will be about 2 1/2 times outside air temp . So if you are doing this on a sunny 90 degree day , 90 x 2 = 180 , plus a half is 270 .
Good Luck.
Follow Ups:
|