1998 GC Laredo AC help.

SherylUpchurch · #1 06-14-2007, 10:27 AM

Hi, You can tell it is summer with all the AC questions!!! I hope someone can help me. I bought my jeep in October 06 and the person that owned it said they never used the AC cause they don't like it. (ARG!! Can you believe that!!) Anyway, I brought it to an AC guy and he tested it for leaks and charged it up for me. He said there were no leaks that he could find. It works to a point. If I turn it on it takes a good 20 miles or so before it actually feels cold. (I have a 45 mile commute) Does anyone know what might cause that.

SteveB05 · #2 06-16-2007, 07:53 PM

So once it cools off, does it stay cold? Is there a big difference between the vent temp when you are stopped compaired to when you are moving?

SherylUpchurch · #3 06-18-2007, 07:25 AM

Hi,
Yes, once it cools it stays cool. When I stop it stays the same temp, I don't notice a difference.

dksob81 · #4 06-18-2007, 04:36 PM

Do you have the ATC (Automatic Temperature Control) aka Climate Control.

If so, turn both knobs to AUTO and AUTO HI and see if it gets colder.

I have a 98 Grand Cherokee and if I have it on the VENT and the RECIRC button pressed the air from the vents gets down to about 35 degrees, if the air is coming in from the COWL (outside air) then the air from the vents is only about 50 degree (maybe a lil higher). and whenever you first turn it on it automatically coming through the COWL, so I have both the knobs turned to AUTO and AUTO HI so it will already select RECIRC and the jeep will be cool when I get in it (using the remote starter).

SherylUpchurch · #5 06-19-2007, 07:49 AM

I do not have the fancy knobs. There are just the dial knobs.

dksob81 · #6 06-19-2007, 04:28 PM

maybe it is a lil low on freon still. Should have 1.63 lbs of R-134a

Check to see if the compresor clutchs are cycling on and off. It shouldn't take that long to cool down maybe a couple minutes (Idling, even quicker if driving).

When my Expansion valve was clogged my pressure reading (high side and low side) were high and it would take a little while for it to cool down, but would never get real cold like now, but driving on the highway it would get to a comfortable temperature.

SteveB05 · #7 06-19-2007, 10:34 PM

Okay, sounds to me like it has too much oil in it. Was oil added with the last charge? I would replace the dryer and while you have it open, change the o-tube, then charge it with the proper weight of refrigerent (as Joe stated). A good amount of oil will be removed with the dryer. Was the system empty when you took it in? Could also be moisture in the system (same fix).

SherylUpchurch · #8 06-20-2007, 08:47 AM

Actually dksob81 you are right, it never really gets "cold" it is just better then it is outside. LOL. How hard is it to change the Expansion Valve? IS that something I (or my husband can do)? Steveb05 what is involved in doing what you are suggesting??? Thanks

SherylUpchurch · #9 06-20-2007, 09:03 AM

When I brought it in it was blowing warm air. I had nothing!!! They mechanic said he put in 1 lb cause it still has some in it. He told me that this system will shut down when it gets low on freon so it doesn't ruin any parts!! I know I know it sounded weird to me too!!!

dksob81 · #10 06-20-2007, 04:20 PM

Quote:

Originally Posted by SherylUpchurch

When I brought it in it was blowing warm air. I had nothing!!! They mechanic said he put in 1 lb cause it still has some in it. He told me that this system will shut down when it gets low on freon so it doesn't ruin any parts!! I know I know it sounded weird to me too!!!

My jeep was the same way no A/C at all just warm air, but I had nothing in it either so I was expecting a leak (Evaporator Core is very common among jeeps and dodge trucks) but no it kept the freon in the system but both my reading got really high after awhile. And STEVE suggested replacing the ORIFICE TUBE/EXPANSION VALVE and I did that now my a/c works great.

dksob81 · #11 06-20-2007, 04:36 PM

I would have the shop recover everything in the system, vacuum it down and add the correct amount (1.63 lbs), then get a copy of the readings from the guages (high side and low side) at the time,also take note of the ambient (outside air) temperature at the time. Steve may be right it, if they added oil when they did the recharge it may be too much. My readings were too high which indicated an OVERCHARGE OR MOISTURE IN THE SYSTEM, which neither were the case, it was actually a blockage int he expansion valve.

SteveB05 · #12 06-20-2007, 07:55 PM

Well, some technical info here first.

The o-tube is essentially the expansion valve for this and most modern vehicles. Rather than having an actual valve, they have a plastic tube with a very small opening in it that gives you the pressure differential between the hi and low sides of the system. There is also a screen on the hi side of the tube that can get clogged or in some cases rips and allows junk to get into the orifice and clogging it.

The dryer is a big can that has desiccant in it to remove moisture from the refrigerant. Moisture does two things, 1) it reduces the efficiency of the refrigerant (so does too much oil) and 2) it can react with some types of oil and refrigerants to form a caustic acid, which can eat holes in evaporators. I'm not saying this is going to happen, but with enough it could.

Now to your question on what's involved. You will need some special tools. Chrysler borrowed a bad idea from Ford and put "spring lock" fittings on their vehicles. You will need a special set of tools to separate those fittings. Aside from that, you will need to "evacuate" the system. This involves a machine to recover the refrigerant in the system now and then, once the parts are replaced, put the system in a vacuum to evaporate any remaining moisture and prep the system for the charge. These are not difficult jobs, but you will need to buy or rent the spring lock tools and a vacuum pump. Have your local shop recover and charge the system. The o-tube is in the hard line that runs up the passenger fender and as I said earlier, the dryer is that big can with hoses coming out of it and will come as an assembly with the hoses attached.

SherylUpchurch · #13 06-21-2007, 08:15 AM

Oh Boy, sounds like a job for someone that knows what they are doing!!! I called my mechanic and will bring it to him tomorrow. The only thing I don't know is how much this mess is going to cost me!!! Guess we will find out tomorrow. thanks so much for all the replies!!! Much appreciated!!

SteveB05 · #14 06-21-2007, 08:52 AM

Parts and labor, I'm guessing will be $400.00 to $500.00. The Dryer will be 180 or so, the o-tube will be 30 or so, labor and the evac/recharge will be 200 or so, possibly higher depending on the shop rate. If you were to do this yourself, you would be about 110 for the dryer, 15 for the o-tube, 35 or so to rent a pump and 75 or so to have a shop recover and charge the system. (this is not a quote...just my guess)

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