I live in an area (deep south Texas) that's just hot and humid, ac is a must. 

 

My ac use to blow 45 degree or colder air no matter the temperature humidity outside, recently the ac performance began to degrade. As the ambient temperature increases so does the temperature of the air coming out of the ac. On a day in the 90's temperature of the air coming out of the center vent (temp readings done with max ac, fan on high, center duct) would run from 55-65 and humid air.

 

The ac system is still all original parts from 2002, other than being recharged 2 years ago at the dodge dealer and few weeks ago.

 

After putting gauges on here is the basic findings (center vent temp is about 55-65): 

 

Static pressure is same both sides (100 psi)

 

At idle Low Side 40-55, High Side: 200-350 (ambient Temp, 84-95). The high side does show “spikes”  occasionally, sometimes they are rapid spikes meaning a jump on high side of 50-100+ (low side stays the same as I recall, might go up a bit), then high side drops to previous psi reading, sometimes the high side will start say at 200, then gradually go up does not come down, low side will go up as well, not sure if that means anything ?

 

At 1500-2000 rpm Low side 35-40, high side 200-250 (both sides steady pressure, no spikes etc.)

 

Other findings:

 

The condenser seems to have a the same temperature (running my hand across condenser), anywhere I place my hand. Dryer / Accumulator seems to have good sweating, high side to me should feel “hotter”.

 

When using the gauges I recover some r134a, in the sight glass the color was reddish / brown, is this normal ?

 

Once in awhile (mainly when ambient temperature is 95+) when the ac compressor first starts, you can hear it strain , the belt does slip a bit on the compressor pulley when this happens. Overcharged system ? I evacuated enough freon to start short cycling (thinking overcharged), then added back 1 120z can. This seems to have stopped the “hard start” as I call it, seems to cool just a tad better. Can't test for a hot day as cold front came threw last night.

 

Could I have a blockage (orifice or dryer/accumulator), evaporator plugged with years of dirt, ac flush needed, to much ac oil ??

 

Thanks for any help 

Hua?

 

It's replaceable. The whole tube has to be replaced. I'm also 2002 Dodge truck and the tube from RockAuto or Autozone is cheap like $30 bucks. Just release both ends and replace.

tube.png

 

I did replace the entire liquid line as its called. I should have clarified that to replace the orrifce required replacing the entire line, on other auto ac systems I've worked on the orifice tube only had to be replaced, that is the orifice tube was not imbedded within the line, once the line is removed the orifice tube comes out then insert new orifice tube reuse existing line.

 

Auto zone sells a kit which allows one to make the orifice tube replaceable without changing liquid line, kit is 20.00 the orifice tube is 3.00. Basically the you cut out the old orifice install the kit.

 

I replaced the whole liquid line easier lol

 Does the suction line get "beer can cold"? If the evaporator is dirty the suction line should actually get so cold it can ice up on the outside. 

 

I'm rereading all the tips in this thread as I have missed something somewhere.

 

I notice the other day that the suction line was obviously cold all the way to the compressor as I could see it sweating a lot "beer can cold".

 

If I understand this corretly this indicates the evaportor has restricted airflow or plugged from dirt etc. 

 

What other effects would a dirty plugged evaporator have on the ac system ?

 

Is it also possiable for a condensor to have no leaks fins in good shape but due to age the condensors ability to give up heat degrades causing poor ac performance ?

Edited June 15, 201410 yr by tonyjsan

A dirty evaporator will cause the symptoms you are having. The suction line will be cold no matter if the evap is clean or not since the system will cycle on the low pressure switch. Have you by chance checked the blend door on your truck?

A dirty evaporator will cause the symptoms you are having. The suction line will be cold no matter if the evap is clean or not since the system will cycle on the low pressure switch. Have you by chance checked the blend door on your truck?

 

What is the best way to check the blend door ? This is the blend door that is controled by the tempurature knob. ?

Yes, the blend door is the one controlled by the knob on the dash. The symptoms are just exactly what you said is going on. Here is a little bit of reading: http://dirtyshirt.info/auto_dodge_blend_door.html

Decided to replace evaporator. Run into problem ac lines at accumulator refuse to come apart 3 hours no luck

Last time they came off easy. Yes using the cheap *** plastic tool.

Any suggestions? Fixing to get the dremel out cut the freaking things off

Slide the tool into the lock. The while hold pressure against the tool twist lightly back and forth of the pipe to free the o-ring. Now it should come off. Typically that's how I free a connector the rocking back and forth will seem to get some oil on the o-rings and get it to slide off for you.

Evaporator plugged bad and leak

Edited June 17, 201410 yr by tonyjsan

Evaporator plugged bad and leak

Secret. Any time your off road or in dusty conditions make sure to be running MAX A/C to close the air off from outside so you not drawing dust into a sweaty evaporator.

Well after changing out the evaporator, heater cored checking hvac box. 

 

I still have an ac that is unable to cool when temps get above low 90s,  below low 90s works fine. At this point everything in the ac system is new. 

 

The symptoms, if travelng at high ways speeds with ambient temps above low 90's some cooling occurs much better now evaporator is replaced.

 

If driving in town ambient tempe above low 90's poor cooling vent air is 60 at best, in time the comprssor will kick out to very high, high preassure i'd say 450-500, then once preasure drops down compressor kicks back in and you can tell it's straining to start.

 

In ambient temps above low 90's in stop and go traffice ac is not  usable at all due to the compresor cycyling and and high side preasure being so high.

 

Engine does not overheat at all, 

 

Assuming the new ac parts are not failed or I screwed somehting up, could the intercooler and radiator be dirty enough to cause poor airflow over condensor, but the engine still cools okay. 

 

Has anyone hooked a secondary fan to the ac condensor if so how is it working ?

 

When the fan clutch kicks in (which is also now), while in stop go traffice etc, seems like the cooling starts to want to work.

 

Open to suggestions.

Almost sounds like its over charged in compressor oil.

Almost sounds like its over charged in compressor oil.

Have you actually checked the compressor? When it shuts off the pressures should get a lot closer to each other and there should be no strain on it. Is it possible that it is overcharged?

The reason I would know about the oil issues is I've got the same problem on mine. I'm slightly over on the oil so it pumps for about 1-2 second and grunts then its gone. But to watch the gauges the pressure spikes out for a short time as the oil is pumped. But I knowingly added a 8 oz bottle to the compressor knowing I was going to spill some of the oil trying to get most of it in the tiny hole with a tiny funnel. Then I changed my accumulator/drier and orifice tube and assumed the little oil in the rest of the system would be minimal. Nope. Just a tad over done on the oil. But my OE compressor only had barely 1 oz of oil in the sump and it holds 7.1 ozs.     

Well it's been months since this project was sort of completed, lol. Thought I'd share the few additional things I discovered as I did this.

 

I did take it to an ac shop and they charged it to factory specs, back in June.

 

I still have the poor cooling problem (when idling outlet temp climbs to 60+) when freaking hot 90+ degrees in the South Texas sun, when not 90+ plus works great, so at this point I'm feeling like 98% it's a air flow issue over the condenser, before summer 2015 gets here going to pull the radiator and intercooler take em to a shop to be cleaned. Also going to replace the clutch fan with one from the dealer, so far I've been threw 2 of them, hayden first one I took back as it failed within a month of install. Anyone know where I can get a good high quality clutch fan ?

 

One other thing, when idling or stop and go traffic (when 90+) if I turn the fan down to lo or say 2nd fan speed  setting, it will maintain cooling. If not 90+ works just fine.

 

In a previous post in this thread I posted that, I had lot of difficulty getting the liquid line to separate and re-install as well, I found out that to get enough clearance I had to remove a bracket that was designed to hole the stock air cleaners, air opening. Once this bracket was removed, install and re-install was a breeze.

I would clean the condenser really good with simple green and a high pressure washer. Do this several times. You be surprised of how much bugs and junk get pack in. How the fins are they all bent up? Straighten them out if so. Fan clutch only comes into effect when the coolant temp rises over 210*F then it locks up. Beyond that it should be free spooling.

 

I'm curious what pressures your seeing? (Lo and Hi)

 

Your 90+ temps down in Texas are just as much as our 105-115*F here in Riggins, ID. But I still can hold a consistent 40*F at idle in 100+ heat. 

i had to replace my wet line during rebuild. i started refilling but i cant get the compressor to kick on. may have to manually trip the switches to get it flowing.

I use a bucket of hot water for discharging the cans into the system. If your waiting for the gas to generate and flow you might be in for a long wait been there done that. I typically use hot water to push it into the system. Most Dodge trucks need three 12oz cans. That roughly speaking. I normally tune and tweak the pressures to keep the compressor running solid. But I've never had to jumper a compressor yet to fill it.

even from bone empty? so you put the refrigerant cans in hot water sitting upright and let them fill? or let them sit in hot water then turn them upside down and fill

From what is typical you would fill with GAS or upright on the lo side only.