BodaciousBlue

Ok guys I'm looking at the aluminum pressure line (passenger side of engine) and I see two protective dust caps. One cap on the pressure line is located near the fire wall and the other cap is next to the container that holds the anti freeze. The instructions says to locate low side service port of AC system. Well, I don't know which is the low side. Need an experts advise to connect the hose to the right service port, and recharge my AC with R-134a. I appreciate all of your help!!! :yesnod: :yesnod: :cheers:


[Modified by BodaciousBlue, 2:27 PM 7/2/2003]

hrdtopv8

I'm stumped on this as well :confused:

Ddaanc5

It will be the larger line returning from the cab. How do you know the AC is low? It is improtant not to overcharge it or the line pressure will go up out of range. I'm assuming you have one of thoes cans with one line. My '98 AC has never covered the heat load of the car in LV, or arizona. This new 'freon' is not supposed to get the output air down to 32 degrees as the old systems did, but mine is within specks so I have not messed with it. If you want to take the chance that it needs one can of coolant alse be sure to attach the line quickly so as not to let too much pressure excape, or you could wind up low on oil in the sustem. a sight glass would be nice. I'll look in my manual to be more spacific. Someone else probably knows which line is low. :D

BodaciousBlue

Any additional help from the CF family. :seeya

Tom Hall

The proper way is to Evauate the system and weigh the charge in. The C5 only holds 1.68 lbs and would be very easy to overcharge.

SFVetteman

The low side is the line that runs from the compressor to the evaporator. The high side is the line that runs from the compressor to the condensor. By the way, the line that runs from the condensor back to the evaporator is called the liquid line.

To do the job right, you need a set of A/C gages.

vetterdstr

Is your AC not blowing cold? What temp does it blow now? (use a pocket temp gauge in the vent to find AC temps)

vetterdstr :cheers:

BodaciousBlue

The AC is blowing cold air, but it takes a few minutes to get to that point of coolness. The process sounds a little more technical than I thought. I'll get professional mechanic to recharge the AC system. Thanks guys.

SFVetteman

When you shut the engine down or turn the A/C off the pressures throughout the A/C system equalize. The next time the A/C turns on it takes time for the high side pressures to build up and the low side pressures to drop. Since the compressor is engine driven the amount of time varies depending on engine RPM.

Like vetterdstr said, get one of those instant read pocket thermometers and check the temp at the vent. You will want to do this with all the windows and doors closed and the A/C set to the coldest temp and the max cool mode. Use the vent closest to the evaporator. Rev the engine to 2000RPM and check what the vent temp drops to. It should be about 45 degrees at 70 degrees outside ambient and 40% humidity. Lower temps and/or humidity result in a lower temp and higher temps and/or humidity result in a higher temp.

If the vent temp is out of line then you have a problem but it may be unrelated to the refrigerant charge. Adding refrigerant when none is needed or adding too much could result in damage to the compressor.

If you need to have the system serviced, make sure it’s done by a shop that has the machine that can recover, evacuate, and charge the system. It’s required by law and most shops have them but stay away from the ones that don’t. While the job can be done with a set of gauges and a vacuum pump, it’s not the best way to do it and runs the risk of undercharging or overcharging the system. In addition, the machines can also identify if you need to have your accumulator changed.

The accumulator stores refrigerant in the system but more importantly it removes moisture from the system. Over time or if there has been a leak the accumulator may have maxed out its ability to remove the moisture and may need to be replaced :cheers:

vetterdstr

Bill, very good info! :)

vetterdstr :cheers:

BodaciousBlue

Wow...great explaination! Thanks. Like you said best to take the car to a mechanic that has all the right tools and equipment to do it right. Thanks for time you put into your post about AC functions. :cheers: :thumbs: :cheers:

CP

If you don't know which port is which, you really shouldn't be trying to recharge the system yourself.

2kbluestreak

The high pressure, liquid line, should be warm when the system is running. The low side, suction line, should feel cool. If this line does feel cool with maybe some condensation, you probably don't need to add refrigerant. :cheers:

Fast one

The fitting closest to the firewall is where to put in refrigerant and where to check low pressure. The fitting toward the radiator is where to check high pressure. Autozone sells a kit for $30 that has most of the hardware including gage but only one hose as well as a graph of pressures and temperatures. I had a fill hose setup already so the high pressure could be monitored as the can emptied. The system took about 3/4 can or 8 oz, about 30 minutes of idling. This yielded a high side pressure of 320psi at 1500rpm at 105 degrees F underhood. There must be detailed help online, check Google.

383LPE

FYI - high side of 320 is too high for 134a.

You can do it yourself and it is better with the right tools. Also, as DIYer, you dont need a recovery machine.

I have a pocket type thermometer in the vent of every vehicle I own. It tells me exactly when something is up. I just finished my wifes dual air split system on her suburban. Nice cool 45-49 out of the vent at 100' ambient.

You CAN do it.