2006 Dodge Durango Issues

[dsar592]

Hello to all. It's amazing how many forums I belong to, most of them hunting and fishing, and yet now this one. I'm going to try and keep this short. About 2 years ago my 2006 dodge Durango 5.7 hemi, 4x4, all wheel drive suv with rear a/c began blowing warm. Took to my mechanic and had new compressor, condenser, expansion valves installed. This guy is good and has fixed other vehicles for me but could not get the ac vent temp below 60 degrees. In south Alabama, that just aint cool enough. So he told me to take it to dealer. Boy did that turn out well!. The said it was two hoses to the tune of $800. Picked it up and on the way home it was blowing 70 degrees out the vents. Took it back to dealer and low and behold the evaporator coil had a hole in it. They wanted 1500 so I took it back to my mechanic who confirmed the hole and replaced the evaporator coil for $700. Still could not get temp below 58 degrees. He added another external condenser fan but it only helped by maybe 2 degrees. Now its hot again outside so I took it to another mechanic friend of mine. He has wired the external stock condenser fan to run when the compressor runs. That seems to have helped. Then he found a leak in the rear evaporator coil and changed it. The issue now is that sometimes the vent temp will be 40 degrees and for whatever reason, start blowing 55, 58, 60, 62 etc... I don't understand it. I have spent about $3000.00 on this system in the last 20 months. My mechanic said he filled the system to the correct amount and the low side read 30 and the high side was 450. That seemed a little high for the high side but I don't know. Any ideas? I'm going to buy a set of gauges. In high school, 30 years ago, I took 2 years of a/c at a vo-tec school. But that was 30 years ago so I obviously need help. Thanks Ken

[Dougflas]

It could be freezing up.

[dsar592]

It was freezing up before this last evaporator change because I could feel the restricted air flow and see ice buildup on the outside of the passenger side evaporator coil. But it would take at least an hour for this to freeze up. I haven't noticed any of that since the rear evaporator change.

[Tim]

A high side pressure of 450psi. Is going to kill performance. Spray some water on the condenser and see if the pressures come down.

Things to look at, condenser fins, fans not working or an over charged system of oil or refrigerant.

[Jag987]

450 is way to high! Does this have a mechanical fan with a fan clutch? That is where I would be looking right now.

[dsar592]

Ok I just put my guages on it and the ambient air temp is 85 degrees. My low side reading is 35 and high side is 200. If Im reading the chart right the low should be between 45-55 and the high should be 225 to 250. So doesnt that mean my system is low. I let it run for about 20 minutes with no change. Also when I initially hooked up the guages both pressures were equal at 94 on low and 95 on high. Well I guess that would be considered equal. So any advice would be great.

[Jag987]

Ok I just put my guages on it and the ambient air temp is 85 degrees. My low side reading is 35 and high side is 200. If Im reading the chart right the low should be between 45-55 and the high should be 225 to 250. So doesnt that mean my system is low. I let it run for about 20 minutes with no change. Also when I initially hooked up the guages both pressures were equal at 94 on low and 95 on high. Well I guess that would be considered equal. So any advice would be great.

How was the vent temp? My problem with the charts is they are made to be a guide. There are many things that will cause your reading to be different and still acceptable. Things like if it is in direct sunlight or shaded, relative humidity, and if the doors and windows are opened or closed can all change vent temps and pressures. That is why so many people advocate having systems recharged by weight according to manufactures specs. When the system is off, the high and low sides should pretty much equalize so your 94/95 is fine. But that brings up another thing, quality tool and equipment. Are you gauges accurate? I have two good sets so I can verify if I think one is off or for the rare occasion I'm working on two systems at once. Stick around, we will do our best to help you figure this out.

Oh, read my signature line. And yes, I am being sarcastic there.

[Dougflas]

Ok I just put my guages on it and the ambient air temp is 85 degrees. My low side reading is 35 and high side is 200. If Im reading the chart right the low should be between 45-55 and the high should be 225 to 250. So doesnt that mean my system is low. I let it run for about 20 minutes with no change. Also when I initially hooked up the guages both pressures were equal at 94 on low and 95 on high. Well I guess that would be considered equal. So any advice would be great.

At what RPM are you getting these pressures?

[dsar592]

I didnt look but the engine was at idle.

[Dougflas]

Idle could be the reason you're getting high low side and low high side readings. Step the idle up to 1500 and post those readings. You may find you're actually slightly undercharged. Low side should be about 35 and high side 230 to 245 at 1500.