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Grover
05-25-2011, 02:18 PM
So, here is a long account of the A/C system in my car. I will be taking it out to Rob Grady for a third time next month and really want this issue solved. Any ideas would be greatly appreciated.

The evap. Box in the car was always leaky since I picked up the car. I planned to have it taken to Grady to get fixed (which I did), but before I got there a heat shield fell off the car, causing one of the A/C hoses to crack and release the Freon. So here is the sequence of events (ps. A/C was FREEZING cold before the hose cracked):
1.) Brought car to PJ Grady. Hoses replaced with split hoses, a/c evaporator core, Replaced when box was out to get leak fixed, upgraded from early style accumulator connections to later style (with high pressure switch, orifice tube was replaced).
After this visit, the A/C made an audible sound as the pressures changed (from the evap box area) which never happened before. I am told this is how it should operate, and upon being in other cars, I have observed this as well.

After taking the car back and driving around, the evap. Box was still not draining the water and would spill all over the passenger footwell.
2.) I took the car back to PJ Grady, and has the box removed a second time. It was found that the box was deformed and a new box was needed (entire assembly). The entire assembly was replaced. No more leaks!
a. But, the A/C was NOT cold, no where close. It was almost unbearable to drive in the summer. Also, that winter, I found the defrost wasnít working (or any heat for that matter). It turned out that the knob that controls the Hot/Cold flap was stuck on part of the evap housing. I fixed and moved it to allow for the flap to move again.
b. Even since fixing this, the A/C does not blow cold. For example, on an 80 degree day, the air outside having the window down is cooler than that coming out of the vents.
c. I no longer hear the flaps move (is this because the foam on the flaps was replaced in the new box?)
d. The compressor cycles at the correct time (about 10-11 seconds), and both radiator fans come on as needed
e. I had the Freon checked last summer, it just needed a VERY SLIGHT fill up, but it still did not blow cold.
f. From a thermometer I used, the change in temperature from outside was AT MOST 15 degrees cooler. So if it was 90 degrees out, the coldest I got it was 75 degrees, in the shade, in my garage, on Max.
So, what could be the problem here? I am taking the car out to get a dent repaired but wanted to have the A/C looked at. Instead of troubleshooting on the spot, I figured it would be ideal to have a list to go through that the community puts together. I really want this fixed as it is almost unbearable to drive the car, and after being in other Deloreans, I know that something is wrong (some are so cold it has to be put on speed 2, I need mine on speed 4 just to get enough air flow to cut through the hot air in the car).

Ideas I have come up with:
When the box was replaced, the flaps are stuck or not functioning correctly, diverting hot air into the cold air.
Compressor dying?
Accumulator needs replacing?
High/low pressure switches need to be adjusted/tweaked
Could the condenser be blocked?
Orifice tube blocked, even though itís new?

The car still drips water and drains, so to me itís functioning correctly, but I just never get cold air. Also, the mode switch was replaced when I first got the car 3 years ago when the a/c was functioning fine, and continued to do so afterwards.

I am at a loss and any information/troubleshooting suggestions would be very helpful, thanks!

Cory W
05-25-2011, 02:27 PM
Are the vacuum hoses hooked up to their respective flaps (actuators)? You won't get the airflow if the flaps can't open.

Grover
05-25-2011, 02:47 PM
Cory, thanks for the response.

When I was replacing the dash I took note of all the lines. The colors match up to where they are supposed to be on both the back of the mode switch, as well as the different actuator points on the box. I followed the colors and diagrams of the workshop manual.

Bitsyncmaster
05-25-2011, 03:18 PM
Did you change to R134a? Are you using the standard orifice?

Did they run pressure checks?

Grover
05-25-2011, 03:37 PM
Did you change to R134a? Are you using the standard orifice?

Did they run pressure checks?


I decided to stay with R12. I'm not sure which Orifice tube was used. I think maybe the one Hervey has, as I know Rob gets some of his A/C parts from there.

As for the pressure, I'm not sure. I think that is something you would see when adding some right? If so, then the person who topped it off said it looked fine.

Bitsyncmaster
05-25-2011, 03:54 PM
I decided to stay with R12. I'm not sure which Orifice tube was used. I think maybe the one Hervey has, as I know Rob gets some of his A/C parts from there.

As for the pressure, I'm not sure. I think that is something you would see when adding some right? If so, then the person who topped it off said it looked fine.

I got less cooling with VOV orifice that Hervey sells. It may work better if your system is very clean (all new parts).

If your condenser is not clean it can limit your cooling but that should show up with pressure tests when your charging the system.

axh174
05-25-2011, 04:05 PM
Technically this shouldn't be an issue because the door flap is supposed to move and cut off air flow through the heater core, BUT, is it possible the hot water valve that diverts engine coolant to the heater core is not fully closing when you stick Max AC on? :dunno: (I'm assuming you are testing with Max AC)

If it's not closing, and your flap is not sufficiently moving to cut off air flow to the heater core, then it's feasible you're getting a mix of hot/ambient air and cold air.

nullset
05-25-2011, 04:16 PM
There's no way to tell how much refrigerant is in there without evacuating, storing/measuring, and recharging it.

The only thing you can really tell from the pressure is whether or not there is ANY liquid refrigerant in the system.

You need to get some gauges and look at the pressures to determine if the A/C is working properly or not from that side. It sounds like your problem is more related to air flow/directions.

--buddy

Grover
05-25-2011, 04:28 PM
Technically this shouldn't be an issue because the door flap is supposed to move and cut off air flow through the heater core, BUT, is it possible the hot water valve that diverts engine coolant to the heater core is not fully closing when you stick Max AC on? :dunno: (I'm assuming you are testing with Max AC)

If it's not closing, and your flap is not sufficiently moving to cut off air flow to the heater core, then it's feasible you're getting a mix of hot/ambient air and cold air.

I have put the A/C on max and have seen the Heater Control Valve change/move by looking behind the engine.

Malevy
05-25-2011, 04:52 PM
Do you hear the flaps move at all when you move the control?

If you turn the temperature to hot, does it get hotter?

Grover
05-25-2011, 05:16 PM
Do you hear the flaps move at all when you move the control?

If you turn the temperature to hot, does it get hotter?

Since I got the car back, I do not hear the flaps move. I assumed it is quiet because of the new foam installed.

As for does it get hotter, yes it does when you move the heat/cool knob.

Malevy
05-25-2011, 10:43 PM
SO, you feel air.. it is just not cold. I am wondering if the temperature flap is not closing all the way..

Also, does the low side line get cold? with the AC on, is the receiver/dryer (front passenger wheel well) get cold?

Grover
05-26-2011, 09:11 AM
SO, you feel air.. it is just not cold. I am wondering if the temperature flap is not closing all the way..

Also, does the low side line get cold? with the AC on, is the receiver/dryer (front passenger wheel well) get cold?


Yes, I feel air, and it is not cold at all. Felt like the heat was on the other day.

I will test it this weekend, but as far as I remember the receiver/dryer gets moisture all around it and drips onto the floor.

Malevy
05-26-2011, 09:53 AM
then the problem has to be with the flaps. Either the actuators are not working properly, or there is some internal leak.

Grover
05-27-2011, 01:47 PM
Does anyone have any ideas/suggestions/ways in which I could test the actuators are working properly?

Malevy
05-27-2011, 05:58 PM
Check it with a hand pump vacuum. Move the knob, and see if the actuators are moving. May have to pull the center console to get access