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2000 Durango

bfox on Sat October 13, 2012 8:13 PM User is offlineView users profile

Year: 2000
Make: Dodge
Model: Durango
Engine Size: 5.9
Refrigerant Type: R134A
Ambient Temp: 75°F.
Country of Origin: United States

I know these durango's have a real problem cooling good. I'm just trying to get something out of this thing.
Was blowing 65°F. at best in the summer. My daughters truck and she brought to me.
Back in August, system would pull down to 35 psi low side @ 1500 rpm with blower on low speed. High side was moving between 200 psi then start climbing and might go up to 350 psi. then drop back to 225-250psi No cooling to speak of. If I turned the blower to next speed the system would progressively get worse.
First I put on a fan clutch,,,an aftermarket expansion valve,, and a new dryer. That didn't help a bit and also discovered the evaporator was leaking. Pulled the dash,, changed evaporator,, heater core,, and blower motor. Also sealed around heater core and inside case as needed.
Put on another TXV in the front and the rear unit.
Nothing changed. System still would not cool properly.
Ordered Front expansion valve from Dodge. After that installation,,,, Still nothing changed. Since I had one I changed the compressor to make comparisons. Used a new Sanden. Still No change.
Today it is around 75°F. I jumped across low pressure switch plug,,, clamped the heater hoses and went and drove the truck. With blower on low the vent temp will pull down to 45°. Any higher blower setting brings the vent temp up. At 65 mph and blower on high the Durango blows 55°F. Slow down to 40 mph and vent temp goes up to 65°F. I sprayed water on the condenser but got no real change in pressure. If anything it seemed to climb some. (believe it or not)
I did notice the new fan clutch drops out and all but stops spinning. However the auxillary electric fan seems to pull fairly strong with my hand in front of the condenser.
I need a little help here.
Thank you for your time.

God Bless America.

iceman2555 on Sun October 14, 2012 12:19 AM User is offlineView users profile

There are several factors that need to be answered.
The original problem was 'insufficient cooling' this point what was done to the system. It appears that the fan clutch was replaced, but was the system checked to insure the proper amount of pressure testing...was the system recovered, evac'd and recharged utilizing the correct equipment...a R/R machine or other method of charging that would allow for measurement of exactly how much refrigerant was added to the system. NO CANS---NO PRESSURES
The only method to begin a evaluation of a performance issue is to know the system is properly charged.
The fact that the evap was leaking leads to the belief that there could be possible condenser debris within the system due to lack of lubricant flow....this material tends to settle in the inlet side of the condenser.....and excessive liquid line pressures may not be an indication of this condition. This factor alone could be contributing factor to your lack of cooling.
Also, the system has had multiple parts was the system recharge each time....was the system flushed and cleaned properly...was lubricant added to the system when these parts were changed....was lubricant added to the system when the compressor was changed....did the compressor arrive pre lubed....was this drained to establish a lubricant charge much lubricant in the system can affect performance.
It is felt that first the amount of refrigerant in the system must be established.
The amount or approximate amount of lubricant in the system should be established.
If the system has been charged properly...with a metering pressures...know how much is in the system, then the system could be evaluated.
Pressures are not an indication of a fully charged system...they are a diagnostic tool for evaluating a fully charged system.
Obtain a method to measure temperatures at various positions of the system. There are several thermometers on the market that will accomplish this task. Sears sells a Multi meter with a thermo probe for less than 50bucks. Once a tool is obtained, and the system is properly the vehicle is a high heat load....MAX AIR...HIGH BLOWER....DOORS OPEN...ENGINE AT IDLE...allow the vehicle to operate at this condition for app 3-5 minutes....then measure the inlet and outlet temps of the close to the inlet and outlet ports as possible. Measure the outlet temp of the close to the fire wall as possible. Compare this temperature to the actual vent temperature (prefer center vent). Also what were the ambient temps when the system was 'blowing' 65 degrees?
Were these temps taking at MAX COOL or at NORMAL cooling? Varying engine RPM is good....prefer both at idle and 1500 rpm. Not a fan of water on the condenser....temps tell more about what is happening.
Opps...almost forgot...does this vehicle have 'rear' air? If so, what temps are being produced by the rear unit?
Conduct these evals and post info. But foremost...the system must be completely and properly charged.
It may be necessary to go back to 'square one' that you have a completely clean system, and know the amount of lubricant and refrigerant within the system.
This will require that the system be recovered, opened and flushed completely..both front and rear if equipped. The correct amount and type of lubricant added to the system.....a valid evacuation and recharge with the correct amount of refrigerant.
There is a concern about the fan clutch....does it actually stop rotation.....this should not occur...there should always be slight 20% fan speed to water pump speed. Although it is doubtful that this is the root cause of the lack of cooling.
It appears that parts are being thrown at this vehicle in hopes something sticks.....a very expensive method to determine a cooling performance issue.
Evaluate the results....perhaps there is a 'fix' without going back to 'square one'...but often times it is necessary to return the system to a true base line and proceed from there.
Good luck

The strongest reason for the people to retain the right to keep and bear arms is, as a last resort, to protect themselves against tyranny in government.
Thomas Jefferson

bfox on Sun October 14, 2012 11:33 PM User is offlineView users profile

Ambient temp 80°F.
Charge 2lbs with a RR machine. weighs out to 1/4 ounces
Have already measured oil in compressor and balanced system. added 2 ounces PAO.
engine @ 600 RPM with original Compressor on system. oem TXV with new dryer.
max A/C, blower on high, doors open.
Low side 55psi
High side 148 psi.
cond inlet 112°F.
cond outlet 103°F using fluke dual temp meter.
Vent temp @ center vent front 68°F
Rear unit @ 75°F.
Evaporator outlet @ 67°F

Increase RPM to 1600.
low side @ 38psi
high side moving from 175 psi to 225 psi. and back again
Center vent temp 58°F.
Rear unit @ 65°
outlet evaporator @ 53°F.
cond inlet 142°F
cond outlet 112°F

Fan clutch kicked in.
High side drops to 175psi.
low side @35psi
cond inlet 130°F
cond outlet 110°F

God Bless America.

Dougflas on Mon October 15, 2012 6:46 AM User is offline

Looks like the fan clutch to me. When it kicks in, there is the 20* across the condenser I like to see. Sometimes, non-oem fan clutches are not the answer.

iceman2555 on Mon October 15, 2012 1:15 PM User is offlineView users profile

Where these temperatures based upon the doors open or closed?
Was the Fluke meter a 53-2 series and what type thermocouples were being utilized? The posted pressures and temperatures vary a bit...but not too far out of line. It appears the evaporator is starving for refrigerant. A suggestion would be to add 2 oz of refrigerant and re test the system. If a positive change is noted, adjust the charge level according. It is possible the scales/metering of the R/R machine is out of spec. How old is the machine? A variation of charge on this system by 2-3 oz is sufficient to cause this lack of performance.
Could be a TXV out of spec, but since this is a New TXV, error on the side of it being correct. Have seen this same issue with aftermarket this a OE Chrysler valve or a valve the dealer purchased. Insure that the valve has the correct Chrysler markings and part numbers.
The fact that the fan drops out...does offer and area of concern....the fan should never stop rotating and pulling air. A minimum air flow would be acceptable at idle and a cool engine...the fan speed should increase with heat load of the engine....not just RPM...but heat load between the radiator and fan clutch face. Monitor this to determine operation.
Good luck

The strongest reason for the people to retain the right to keep and bear arms is, as a last resort, to protect themselves against tyranny in government.
Thomas Jefferson

bfox on Mon October 15, 2012 6:40 PM User is offlineView users profile

The fluke thermometer is a dual 52 with I don't know which Tcouple it has. I tape one on each side of condenser or use one taped to evaporator. I use hvac tape.
I've already tried increasing charge by 3 ounces. It doesn't change anything but head pressure.
An automotive A/C unit with a 2lb charge will make cold air 6 or 8 ounces low on refrigerant. I see it all the time.
This unit will not get below the posted numbers running 65 miles per hour on Max A/c with all the windows up.
That in my view would eliminate the fan clutch problem.
Also,,, The expansion valve came in a dodge box with the right number on the valve.
I put that on after going thru 2 aftermarket TXV's which I returned for defective.

This has been my problem from the get go. The truck is on the third expansion valve and still no cooling.

I'm going to warranty the fan clutch but I can tell you it won't matter. Highway speed should give some cooling which it doesn't.
Just don't know what to do next.

Thanks for your time,,,

God Bless America.

iceman2555 on Tue October 16, 2012 10:42 AM User is offlineView users profile

Check the max cool/normal ac door. We have encountered various problems this year with this condition. The doors seem to bind or the actuator does not close the door for true MAX operation
Also these are suggestions for additional accessories for your temp tool. This is a very good unit, but these accessories offset a more valid test over the 'bare wire' type thermocouples.

80PK-27 SureGrip™ Industrial Surface Temperature Probe
80PK-8 Pipe Clamp Temperature Probe

Re reading you post, it is indicated that the evap was changed. Was an OE unit used or an aftermarket unit? Just interested, because some of the aftermarket units have flow issues due to the placement of the outlet of the evap where it is mated to the TXV mounting flange.
Also, if possible measure the inlet and outlet temps of the evap. This is a bit difficult with this vehicle due to the placement of the TXV. However, it may be possible to pull the TXV/Evap mounting toward the front of the vehicle to expose the true inlet and outlets. If possible measure these temps....if the system is properly charged, it would be expected to see a temp difference of app 5 degrees.
The evap outlet temps are relative to the indicated vent temps....for some reason the evap does not seem to be cooling sufficiently. Typically this would indicate a 'starved' evap. An undercharged system can actually be cooler than a fully charges system, given a certain heat load on the you statement about undercharged system can valid, however, it can also be incorrect if this undercharged does not produce sufficient refrigerant to properly cool the evap.

These are photo comparisons to OE vs Aftermarket evaps. This could product a problem similar to your. These are not Durango evaps....but the problem could be the same.

Notice the difference in the flow of these two units. This is not the case in all aftermarket evaps...but this could account for a problem similar to yours.
Good luck 1

The strongest reason for the people to retain the right to keep and bear arms is, as a last resort, to protect themselves against tyranny in government.
Thomas Jefferson

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