Och

iTrader: (3)

So can anyone guide me in the right direction regarding my AC problem? The previous summers that I had the car, the AC was ice cold, and this summer it just isnt that cold. The air that comes out from the vents is barelly cool when the car is idling, but once on the highway, its more or less cold... still not as cold as it used to be. Also, I remember last summer, when the AC was on, there were some metal pipes under the hood that were covered with ice frost. This year, theres no ice frost on any lines. I don't remember which lines exactly were they. In any case, what should I look into first?

Blavatsky

I'm having the same issue, and I just got it evac'd, charged, and had the top valve replaced. Maybe a slow leak somewhere? Or that evaporator/dryer behind the headlight is not working right?
Mine gets *cold* , but never icy. It sort of works, but when its 94 degrees like today that just irrates me since I just spend some bucks on it.

skperformance

iTrader: (6)

You need to refill it , get a booster or top off which is just butane and is an amazing refrigerant but highly explosive.

Bill Dowd

take it to an air condition repair shop and let them fix it correctly you are low on freon which after a few years some will leak out of your system. Also in the winter always turn on the compressor with the heat on to exercise the compressor the air will NOT turn cold with the heater on but the compressor needs to be run at least once a week for about 10-20 minutes. This keeps the freon and oil mixed in the system and keeps the seals from drying out. And your compressor will last a lot longer. My 91 lexus with 205,000 stills runs with R12 the old stuff gets the the car cold as hell in the summer.

steveski

Under the hood in the right front is an evaporator bottle - mine has a sight glass. With the A/C on and the engine at 2,000 RPM there should be no bubbles going across the sight glass. If you see bubbles then freon is low. This is how I check mine myself rather than going to a shop.

If you don't have a sight glass then you must take it to a shop so they can hook gauges up to test pressure, etc.

It is cerainly not uncommon for the system to experience leaks - even on newer vehicles.

heyhowyado

it may be the excessive heat the last few days is making you THINK it's not working as well....wait til we get to temps a little cooler and see if you feel the same way...

with temps in the mid to high 90's (and very humid), it's hard for any cars AC to do a great job.....

Och

iTrader: (3)

Does a 94 LS use the old type of coolant or the new?

BCP43002

Did you check to see if you are properly charged or leaking? Try these steps first:

A complete check of the mechanics and performance of the A/C system
will quickly reveal areas in need of attention. You can perform simple
and easy-to-do sight, sound and touch" checks before starting the
vehicle or attempting to run the A/C system. These include:
1. Verify outlet temperature (35° 45° F) with a Performance Test (see
Performance Testing in this section).
2. Coolant Level  An overheated engine will not achieve full cooling
performance.
3. Compressor drive belt tension  At full load, the compressor
requires high drive torque to drive the belt. The Vehicle Repair
Manual specifies the correct tension.
A blinking A/C light indicates a possible compressor lockup situation.
After making any necessary adjustments, carefully observe what
happens right after starting the engine and switching ON the A/C.
4. Listen for the loud click" that indicates the compressor clutch has
engaged (energized). Observe any unusual compressor noises.
Confirm that the electric fans immediately run at low speed.
5. Look into the sight glass (on receiver-drier, if available):
• It should appear clear, as liquid refrigerant with a few bubbles of
vapor flowing out of the receiver-drier (an almost empty system
will also appear clear).
• Excessive bubbles may indicate an undercharged system.
• A cloudy flow indicates the desiccant has escaped from its bag
container or there is moisture in the system.
• If there is no movement visible, just cloudy streaks, the system is
empty.
6. Carefully touch accessible refrigerant lines to confirm system
operation:
• Low-pressure lines should feel cold to the touch. In humid
weather, moisture may condense on these lines.
• High-pressure lines should be hot to the touch.
• A high-pressure line that feels cold indicates a pressure drop due
to an obstruction in the system such as a clogged fitting or a
crushed refrigerant line.[/QUOTE]

BCP43002

Heres .02 more, hope it helps:

A variety of maintenance conditions can affect the A/C system that
may not be revealed by standard diagnostic procedures.
• If a system does not blow sufficient air, check for obstructions of the
fresh air intake or body exhauster vents outside the vehicle.
• Restricted (clogged) fresh air filter behind glove box needs replacement.
• The expansion valve may fail in the open mode as a result of debris
in the system (perhaps from a past malfunction). The expansion
valve can also seize in the closed position due to a loss of lubricant.
Apparent expansion valve failure may simply be a case of the
capillary tube (sensing bulb") not being in contact with the
evaporator outlet line.
• Paper, leaves and mud can clog the condenser fins. This reduces
system performance and can cause overheating and a blown fusible
plug or relief valve. The debris can often be blown out with
compressed air or a water hose. If necessary, special combs" are
available to straighten bent condenser fins.
Clearing
Condenser
Obstructions
Bugs or dirt will increase
system pressures and
reduce cooling efficiency.
• A system which does not produce cool air or blows a visible mist
(even though the fan works) may have one of two malfunctions:*
1. An iced evaporator. This can be caused by using MAX cooling
with a low fan speed or a failure in the thermistor/amplifier unit
(to be discussed in A/C controls).
2. The evaporator drain hose may be clogged with leaves or mud
which will cause the evaporator housing to fill with ice and
water. This will restrict airflow. A wet carpet is one symptom of
a clogged evaporator drainline.
* Some mist or fog can normally occur on humid days when the
system is first switched ON.
• A simple way to check the operation of the electric fan system is to
unplug the coolant temperature switch or refrigerant pressure
switch while the ignition is ON. This will result in the fans running
at HIGH speed.

Every system will slowly lose refrigerant through the front
compressor seal, especially if the system is unused for long periods
and the lip seal dries out. It is not unusual to lose half a pound each
year. At this rate, the system will lose its effectiveness in two to
three years. This slow leak will not be apparent during normal
maintenance and is too small to be detected with a leak checker.
• A system that loses more than half a pound per year has a real
leak. Leaking front seals may be easy to diagnose due to the oil
stains on the clutch and in front of the compressor. The seal is
easily replaced and on some models it can be done without
removing the compressor. When handling the front seal, always
coat your fingers in oil to prevent body oils and acids from etching
the delicate sealing surface.

damon

94's are 134A.

damon

BCP,
Is that a cut & paste answer or are you a professional?

I not only added some 134 A the other day but also took in 4 oz of BG Frigi-quiet II. Seemed to help my compressor run smoother.

thanks, mark

BCP43002

Cut & paste but I work on the weekends

damon

Ah, a semi-pro then.
Lots of great info in your post.


How in the hell are you supposed to know if the ratio of oil to 134A is at proper operating levels.
I would assume you loose both over time?

Nhtach provided me with this info for a 10PA20C compressor:

"The factory calls for 4oz of oil into the compressor. The total factory system fill is 6.5oz, I did 8-9oz oil POE100 into my system with 6oz into the compressor/2oz into the dryer/rest into the system".

BCP43002

I think you need a 3 R(Recovery-Recycling-Recharging) station to tell exactly what your ratio is.

As far as what type of oil, you can use this chart:

Compressor Type: Refrigerant : Recommended Oil
Piston (reciprocating) : CFC-12: ND-6
Scroll or Rotary Through-Vane: CFC-12: ND-7
Piston (reciprocating): HFC-134a : ND-8
Scroll or Rotary Through-Vane: HFC-134a : ND-9
Hybrid Electric: HFC-134a: ND-11

Do not mix the different types of oil together. Not all types are
compatible.

As far as what % of the oil is where 50% sits in the compressor, 20% in the evaporator, 20% in the condensor, 10% in the receiver - drier

BCP43002

You could also look at the sticker under your hood to see what type you have and what type of oil. On my GS it is behind the grill.