A/C Question

[jerrymac]

I have a 97 Eldo ETC and the A/C just doesn't seem to be cooling as good as it used to.

I didn't place a thermometer in the vent to check actual output air temp. , but it just don't

feel quite as cold as in years past. I am assuming that the system is not extremely low on

refridgerant as there is no info on the DIC stating that it detected low refridgerant level.

What I was gonna do was to recover the refridgerant to measure the charge amount,

then vacuum it down and recharge with the proper amount to see if it helps . The problem is

that I don't see any sticker under the hood anywhere that states the proper amount.

Can any of you guys tell me what the proper A/C charge amount is for a 97 Eldo? Thanks!

[Cadillac Jim]

This should be on a sticker on the compressor or under the hood somewhere. From the 1997 FSM page 1B-35, all models have these capacities:

R-134a Freon: 2.00 pounds (0.91 kg)

Refrigerant oil:

Compressor - 2 fl. oz. (60 ml)

Evaporator - 3 fl. oz. (90 ml)

Condenser - 1 fl. oz. (30 ml)

Accumulator - 3.5 fl. oz. (105 ml)

You should make sure that there isn't a simple external problem or a blockage before you recover the Freon. According to the FSM troubleshooting chart on page 1B-12, you should start by running the codes. Here's how to bet the OBD II trouble codes:

<a href="http://www.caddyinfo.com/readingcodes.html" target="_blank">http://www.caddyinfo.com/readingcodes.html

</a>

If finding and fixing problems revealed by the codes doesn't fix it, the highlights of the three-page troubleshooting chart for insufficient cooling on pages 1B-12 through 1B-14 are:

• Clean the condenser of dirt, leaves, etc.
• Make sure that nothing is between the condenser and the radiator.
• Examine the condenser and A/C hoses for dents, kinks, etc.
• Observe the A/C compressor with the A/C on and make sure that the clutch isn't slipping.
• Look at the cooling fans with the A/C on. The left-hand fan should be operating at low speed and the right fan should be operating at high speed (this may be incorrect -- I believe that both fans should be on low speed).

If all the external things are OK and it still doesn't seem as cold as it should be, then you need to look at the Freon and such. Push the temperature knob in, which resets any switches and puts the A/C on Auto, and put the temperature down to 60 F, which turns off the temperature control and puts out the coldest air at high fan speed. Give it 10 minutes with the car moving 30 mph or faster and see what you think; make sure that the vents you check for cold air are on. The air should be at least 15 F cooler than the outside temperature at high humidity (over 50%) and 25 F cooler than the outside temperature at low humidity.

If that doesn't do it, observe the compressor over a period of time. If it cycles, then there is an obstruction in the system.

You can charge the system using pressure gauges if you have them. With the system operating for 10 minutes at 80 F outside temperature, the low side pressure should be about 45 psig and the high side should be 260 psig. Low side can vary about 10 psig and the high side can vary 30 psig due to humidity. Higher pressures mean that there is an obstruction or the system is overcharged. Lower pressures mean that the system is undercharged.

One thing I've seen in other cars is that running without the air flow shield between the bumper and the bottom of the radiator exposes the condenser to road debris. Over a period of time the condenser picks up tiny leaks and the A/C will need recharging more and more often. The only cure is a new condenser and a replaced air flow shield. People knock those shields off parking in lots with those concrete tire stops and don't replace them. It takes a year or so of occasional highway or freeway driving to ruin the condenser.

[KHE]

jerrymac, If you have recovery equipment, the easiest thing to do is what you described. The system capacity is 2.0 lbs. My guess is that the system is slightly low on refrigerant but not enough to set the low refrigerant code.

If you have a manifold gage set, pressure readings would help - with the climate control panel set to AUTO 60 degrees, check the high and low pressures right before the compressor cycles off.