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My manifold gauge reading

kwoo510 on Thu March 20, 2008 3:46 PM User is offline

Year: 1999
Make: Dodge
Model: Dakota
Engine Size: 3.9
Refrigerant Type: R134
Ambient Temp: 70
Pressure Low: -10
Pressure High: 125
Country of Origin: United States

I have a 99 dodge dakota, V6. My compressor won't turn on; it's cycling when it wants to and no cool air at all. I hook up my gauage, the low side is -10 and high side is about 125 (when I bypass the pressure switch). It has high side restriction, right? I disconnected all high side hoses and trying to look for the orifice valve. I have no luck. I had done some research; I know the orifice valve should be located next to the condensor, right. I even looked at the inlet of the evaporator, but there is none.

My main question is what would the manifold gauge read IF the orific valve is missing?

mk378 on Thu March 20, 2008 4:16 PM User is offline

If you were trying to run without an orifice tube, the low side pressure would be unusually high. That's not what you measured. Was it properly charged when you measured? Seeing the readings you have, the first guess would be that it is very low on refrigerant. When fully charged, a negative low side does indicate a blockage.

Edited: Thu March 20, 2008 at 4:21 PM by mk378

TRB on Thu March 20, 2008 4:46 PM User is offlineView users profile

Have to agree with a low refrigerant level for starters. Not really going to get a whole lot of pressure change without an OT in the system. Compressor just pumps it through with it not doing a whole lot.

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kwoo510 on Thu March 20, 2008 5:50 PM User is offline

I don't think my a/c system is low, in fact I am suspecting it's over charge. I bought the truck last september and found the a/c didn't work. So, I added a can of freon in it that time. It's still didn't work. Since it was in winter, I didn't bother to pull out my gauges. Until last week. I added a can of freon with UL dye in it last week, that's when I took the reading. I didn't see any leaks.

So, you guys recommend me to put the new dryer in, evaluate it and put two cans of freon in to see what the gauge reads?




Chick on Thu March 20, 2008 6:09 PM User is offlineView users profile

I recommend have the refrigerant recovered, a long vacuum pulled and the correct amount of refrigerant put back in, then check pressures. If you added anything other than virgin R134a adn UV dye at any time, you may need a little more work..But first check the pressures when "properly" charged from a vacuum to full.. Leak area's on the Dakota are usually the evaporator..Hope this helps..

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Chick
Email: Chick

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Freedoms just another word for nothing left to lose

kwoo510 on Fri March 21, 2008 1:23 AM User is offline

Here is the result after I flushed the evaporator, hoses , condenser, and installed a new dryer. I evaluated the system for over half hour and waited few minutes; the vaccum stayed at 29-30. I put in 2 cans of freon. The result about the same. Ambient temp was about 70F, The low side read -10 and hi side read 75 and the air at the vent was blowing 88F. The low side hose feels warm in the engine comparment. The clutch wouldn't engage unless I bypassed the pressure switch.

any suggestions?

until this point, I still can't find the Orifice tube. I went to the local part store and flipped thru the manual. The orifice tube should be on the left hand side of the condenser. The tubing coming out of the condenser is like half of the lenght of the dip stick. I swear it has nothing in it; I was able to stick a pencil in it. anyone know where the orifice tube might be at? any pictures?

Chick on Fri March 21, 2008 6:39 AM User is offlineView users profile

First, is this a front air only or dual air. Capacities are "28" ounces for a front air unit only and "32" ounces for dual air. You do need the proper amount in before your pressures will be correct. The O tube will be in the from the condenser to the evap, if dual air, it will be after the line breaks to go to the rear, so that would mean the evap inlet. Dual air has an expansion valve (Block type) on the bottom of the truck to feed the rear evap (passenger side as the line goes up into the truck) So, I'm thinking this is a single air unit? Very hard to have both expansion devices clogged to that much resistance.. So check the inlet to the evap, and also look for "dimples" in the line out of the condenser, if you see them, thats where the O tube will be held. The below pic is of a Grand Cherokee, but you can see the crimps in the line. In this case, the O tube is not replaceable, rather the whole liquid line needs replacing..I just don't remember on the Durango..


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Chick
Email: Chick

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Freedoms just another word for nothing left to lose

kwoo510 on Fri March 21, 2008 4:37 PM User is offline

Mine has only front air. The only dimple I see is right next to the condenser. Again, I can stick a pencil in. unless the o tube is located below the dimple (I don't see how you can get in out because of the bent).






The evaporator tubing (inlet/outlet) only stick out 3-4" from the firewall. The dryer connects to one of the evap. tubing, the other one connects to one of the a/c hose. No dimples. see picture below




Edited: Mon March 24, 2008 at 11:36 AM by kwoo510

steve325is on Fri March 21, 2008 5:32 PM User is offline

The info I have shows a two-piece liquid line, with the orifice tube between the two sections.

-- Steve

kwoo510 on Fri March 21, 2008 5:47 PM User is offline

Quote
Originally posted by: steve325is
The info I have shows a two-piece liquid line, with the orifice tube between the two sections.



-- Steve

Can you share your info?

is it the one that has a ground strap on my second picture?

Chick on Fri March 21, 2008 6:00 PM User is offlineView users profile

Try a wire and see if it hits it, if so you can use an O tube removal tool, or sometimes a long dry wall screw to remove it. But yes, that is where the O tube should be, stopped by the dimples..Hope this helps..

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Chick
Email: Chick

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Freedoms just another word for nothing left to lose

steve325is on Fri March 21, 2008 6:14 PM User is offline

Quote
Originally posted by: kwoo510
Quote
Originally posted by: steve325is
The info I have shows a two-piece liquid line, with the orifice tube between the two sections.







-- Steve



Can you share your info?



is it the one that has a ground strap on my second picture?

There should be a tube fitting in the middle of that line.




kwoo510 on Fri March 21, 2008 6:54 PM User is offline

I will try a wire tonight.

Thanks Steve. A picture worths thousand words. I think it's the one with a ground strap on my second picture. I will open up the insulation to see if there is any fittings in there tonight.

Now, I remember the auto part guy ask me if my truck equiped with nornal usage or heavy usage orifice tube. I had no clue what he was talking about. he showed me the heavy usage O tube picture. It's a pre-bent metal tubing with o tube in it.

anyways... just curious; is there any tricks to check if the O tube any good if mine equiped with heavy usage o tube?

Chick on Fri March 21, 2008 7:26 PM User is offlineView users profile

The "heavy" usage O tube is "most likely" the VOV which causes more problems than they are worth. Take it out and use the Purple O tube your truck is supposed to have..Hope this helps..

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Chick
Email: Chick

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Freedoms just another word for nothing left to lose

kwoo510 on Mon March 24, 2008 11:42 AM User is offline

Quote
Originally posted by: Chick
The "heavy" usage O tube is "most likely" the VOV which causes more problems than they are worth. Take it out and use the Purple O tube your truck is supposed to have..Hope this helps..


Chick, I believe what you say. So far I am unable to find a shop that can cut and weld the liquid line for me.



Here is what I found in the line.

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