Jeep A/C Problem....Help?

[Danny]

I know this is really off the wall and I haven't seen any posts on vehicle problems, but I just hope someone is a Mechanic in our Forum Family.

1999 Jeep Grand Cherikee Lorado 4.0 motor
         When car is in motion we have GOOD cold A/C....
     When car is stopped we DO NOT have any cold air?
Freeon has been checked and is at normal level.  Just don't know.  Help
                           Thanks in Advance....  Danny  :+(

[Gabby]

Not a mechanic by any stretch of the imagination, but it sounds like it isn't turning the pump enough at idle. I'd check the fanbelt first off, to see if it is slipping. If that's OK I would take it to my favorite mechanic.
Gabby

[Russ C]

Vacuum leak or bad vacuum chamber/valve. The doors that control the flow of air, either across the heater core or the AC coils is controlled by vacuum. It defaults to the heater with the help of a spring so when you slow down, low vacuum, no AC. As you speed up vacuum increases witch over comes the leak/leaking valve and opens the door and you have AC. So you have a vacuum leak somewhere in the vacuum system or the vacuum valve/chamber. 

[Danny]

Does anyone know what the A/C CONDENSER (like a small looking radiator) does?  Neighbor suggested this? 

Rick I am not really sure wat your telling me.  The same amount of air that is blowing thru each vent is the same whether in motion or stopped.  Help
          Danny  :+)

[GrayBeard]

Sorry Danny...no help from here.

I prefer 2/60 - A/C...2 windows down and 60 mph!

Good Luck with it!

~~~GB~~~

[Russ C]

The compressor pressurizes the refrigerant and what was a gas becomes a hot liquid. The now-hot liquid refrigerant flows into the condenser which is made up of groupings of long hollow coils filled with the hot liquid, cooling/condensing the liquid.

The AMOUNT of air will be the same in a vacuum leak. It will just be warm stopped and cold when you speed up. The door directs the air. It does not change the flow.

I have fixed two vehicles in the family with a vacuum hose leak doing the same thing.  

[lwilli]

Danny, I'm not a mechanic either, but I do know a little about the condenser. It serves the same function as an outside condensing unit for your central air unit at home. There is a refrigerant that runs through the system and it's job is to absorb the heat inside the vehicle or your house whichever. The heat that is absorbed by the refrigerant is then dissipated to the outside air with the help of a fan blowing across the coil. So therefore the refrigerant is then cooled and then able to once again flow through the evaporator which is inside the vehicle and once again absorb more heat. It's just a continual cycle.

As for the problem that you're having it sounds as though Russ has it figured out. I hope this helps!

Louis

[chief]

The condenser cools the superheated gas refrigerant and turns it into a liquid state again.  If the condenser doesnt get enough airflow the refrigerant will not condense.

[Danny]

Howdy EVERYONE....I have read and re-read all suggestions and think I need the night to digest all.  I have a strong feeling that what you all are telling me will some how lead me to the answer to fix my problem.  Like some one said more than likely I will have to spend money to have a person fix my problem.  Anyway....its....Friday and lets all have a real, real good evening.  Later....  Danny  :+}

[marmoh]

My monies on Russ ....

[dgman]

I'm not a mechanic but What Russ has explained is correct!

[cliveg]

no just come to theuk its always old here lol

[Danny]

Hi Russ....After sleeping on all this information I remember the OLD engines that did have some vaccume hoses that controled different things, but would a 1999 use the same principle?  Where would I look to investigate a vaccume hose in the A/C assembly?  All of you have been very helpfull and I thank each of you.  Danny  :+}