Hi all,

how do you know when it's time to recharge your AC? I've have my expy for a couple of months now and it's only recently been hot enough REALLY need the AC. It blows cold, but it's not super chilly. It doesn't do a real effective job of cooling down the vehicle quickly, especially after it has been sitting in the sun for a while. I notice that when I'm sitting at idle, say at a stop light or such, it will blow cold, but when I'm moving it blows colder. Still not freezing cold, but noticable. It is time for me to recharge the AC or is this normal for expys?

 

You gotta check the compressor under the hood. If it is clicking on for a couple seconds and then off for a couple, then it is most likely low. It is possible that it was overfilled also, as the compressor will cycle like that due to overpressure.

 

First lets clear something up. You never need to recharge an AC system that is leak free. It is a sealed system and in theory is sealed for life. Refridgerant is not considered a consumable material, any leaks should be repaired. With that said, is the compressor cycling alot? With the front and rear ac on high what is your register temp at idle and highway speeds. If you have 50k plus it might not be the AC it could be the clutch fan. If it is warm at idle, cold at highway speed this is your problem. Finally the only way to tell if the system is low is to use a gauge set to look at both the high side and low side pressure. OK that was alot right? If you do feel the system is low there are alot of cheap recharge systems at your local parts store that anyone with two hands can use, but whatever you do, do not use any product on your AC system that has any leak stop additive. It is a total gimic and can cause major problems, if you need more info fire away. Also if there is a leak it is a good idea to add oil also (ester only).

Dave

 

Something on this issue: I have a 97 Expy EB and mine appears to get slightly warm at idel but cools great at speed. Some one told me that it could possible be my clutch fan, but since I am not running hot at temp, they did not think that was my problem. If I am running under 1/2 the temp, could the fan still be the problem for the A/C not cooling properly?

 

I agree, the only real way to know if your system is low on refrigerant is to hook up gauges. And yes, in theory these systems are completely closed and shouldn't need additional charges. Although realistically many do due to the number of hose connections, seals and fittings that are not "perfect" but don't necessarily need expensive repairs/replacements either.

 

I find that without the the rear vents blowing cold air...no matter what I do on a hot day the beast does not cool down enough to suit my tastes (arctic wasteland is my goal)

 

I agree with last post... what I do first usually is go to an Auto Parts store... They usually will hook a guage up for you and check. If it's low a $6 can of R134a will sure beat any costly diagnosis of the system and if that doesn't work your only out 6 bucks and you can go from there

 

6.00 more like 18.99 for a can or r134a now.

 

Don't get me wrong guys I am not saying run to your nearest AC shop for a small leak. Also as mentioned virgin 134a is about 14 bucks a can where I am at. Since his truck is an orifice based system without a thermal expansion valve it is considered a critical charge system based on weight. Charging one of these systems blind or with only a low pressure gauge will work but will never yeild maximum effiency. If it has to be done blind and you know the system is low this method will get you by... With both AC's front and rear on max windows up and engine RPM slightly about 1500 (A brick will help with this). Then slowing add refrigerant and let stabilize. If the system is low the temperature will start to drop, keep adding until temperature drops and comes back up about 2 degrees, don't open doors while checking. This is the best method to get close without doing it right. Right would be to recover the charge and weigh it back in and add whatever more you need. Next to right would be to watch both the high and low side and us a temperature pressure chart. Then the above mentioned procedure, and lastly the add a can and pray. If you add to much it will flood back and kill the compressor.


Itmerill, I have seen many trucks run normal temps and the fan clutch be totally shot. Try this turn on all AC systems to max and let it sit and idle in drive like at a stop light. Then drive off, if the fan is not howling it is shot. Another check is to let the truck idle with AC on and get nice and hot then shut it down and open the hood and try and spin the fan by hand, it should be basically locked up with maybe a slight slippage. If you wanna get real fancy you can use an optical tachometer.

Dave