Need advice from the AC gurus...

[GrantP]

The AC in my 06 has been problematic from the day I bought it four years ago, mostly that it blows warmer out of the passenger and rear vents than the driver side. That's a well documented complaint on this site and the general consensus seems to be that the freon is low when that is happening. In the last 4 years it has been "topped off" professionally and the problem goes away...for a while. I have been unable to find a leak in the system.

Fast forward to last weekend when I was driving down the highway and the AC was blowing cold enough and then it suddenly quit. I took it into a shop that I trust and he claims the compressor is seized and there is no freon in the system. The system will not hold a vacuum for more than a few minutes. Long story shorter, I've ordered a new compressor, condenser, drier, and new refrigerant line with orifice tube. Am I missing anything? What else should be replaced after a compressor failure? Any pitfalls to watch out for doing the replacement? I've never had a compressor fail before and this one only has 69k on it.

Thanks in advance,
Grant

 

[KenHwy61]

I am not a Dodge HVAC expert but do commercial refrigeration everyday. You don't say if you have already, but if you have not, the first thing I would do is find exactly where the refrigerant is leaking out from. There is no point in doing anything else until that is resolved. It sounds like you may be unnecessarily replacing parts. Good Luck!

 

[GrantP]

The compressor is hosed either way, I'm just trying to get a suggested list of parts that SHOULD be replaced after a compressor failure. FWIW the leak may have been from the compressor itself, there is dye all over my oil pan now. There may be another leak somewhere else but I won't know until I get it up and running again. I'm hoping that the slow leak I've been dealing with was the compressor itself and this will fix it but that may just be wishful thinking.

 

[KenHwy61]

You could try putting a little 134a refrigerant in the system to pressurize it. Then get a bottle of gas/vapor leak detector that you can spray all over the system. It will bubble at the leak point. If the leak is big you may actually even be able to hear it. The problem with not confirming and fixing the leak first is when you evacuate the system with a vacuum pump you will suck air and moisture into the system through the leak which you do not want. It is possible the leak was in the compressor but as you said that might be wishful thinking. Murphy's law says the leak is in the evaporator buried somewhere inside the dash!

 

[GrantP]

Murphy's law says the leak is in the evaporator buried somewhere inside the dash!

Exactly what I've been afraid of for the last four years...

 

[cerberusiam]

Only thing I would add is a set of O-rings and replace every single one you can find. Mine has done the same thing for the last 4 or 5 years. Throw a can or 2 of refrigerant it every spring and drive. I have tried dye, I had a shop try dye, no leaks visible but it loses refrigerant. At the age the trucks are it is replace everything, including under the dash, and hope for the best,

 

[Motorhead]

One thing you will have to do also is to flush ALL remaining components that do not get replaced. It is VITAL that the system has ALL debris removed or the new compressor will fail quickly. It is important as said above to get new orings and I will add to make sure that the ones you get are the right size on the "Cross Section" of the oring or the lines will leak. I did a rebuild with new compressor on my '07, 5.9 three years ago at about 70,000 miles. Compressor got noisy. I bought the OE compressor but in the aftermarket. I bought the liquid flushing fluid and a flushing tool that you pour the fluid into and pressurize it with compressed air.
I bought an aftermarket orifice hose and the aftermarket one wasn't built too well. I ordered one from the dealer and also ordered the drier from the dealer. There may be different opinions on this but that's what I did and the system still works well.
Whether it is true or not, I read here on the forums and experienced it with my original factory filled system was that the compressor being mounted so low that when the system was off for a time that the compressor hydro locked due to the freon liquid settling in the compressor. I almost always would hear a grumble when I turned the AC on for the first time. I believe this hastened the compressor failure and perhaps too the leakage of the refrigerant out of the pressure relief valve that is mounted at the bottom of the compressor due to the hydro locking.
I personally ditched the R134 for a different refrigerant composition. It has worked better and doesn't collect in the compressor causing the hydro lock.
One last thing I try to do whenever I turn on the AC for the first time is to do it at IDLE. If I am going down the highway, I put the trans in neutral for a few seconds until the RPM comes down to idle, turn on the AC, match back up the RPM's and put it back into gear. That's me.

 

[Prairie Dog]

I'd like to make sure I understand exactly how to make life easier for our compressors.
>We should let a "cold" truck run for 2 minutes before turning on the AC?
>it's safest to turn it on at an idle the first time. (my compressor hits so hard the first time that I've been startled thinking someone hit me!)
Model year differences?
Anything else?

Thanks,
Scott

 

[Motorhead]

Scott. I didn't say I run my truck for a few minutes before turning it on. My main thought about turning the AC on for the first time of the day at idle means the compressor clutch is spinning at its slowest. When the compressor is hydro locked, the lower the RPM hitting a locked compressor the better.

 

[Prairie Dog]

Scott. I didn't say I run my truck for a few minutes before turning it on. My main thought about turning the AC on for the first time of the day at idle means the compressor clutch is spinning at its slowest. When the compressor is hydro locked, the lower the RPM hitting a locked compressor the better.

Gotcha. Sometimes when it turns on the engagement is brutal, now I know why.

 

[Motorhead]

Gotcha. Sometimes when it turns on the engagement is brutal, now I know why.

I have seen AC compressor lines that had an aluminum chamber can that was right before the compressor. I can't remember whether it was on the suction side or the high pressure side. Since the compressor on the diesels is mounted low, an add on that could be TIG welded to the line and facing down, could catch and store any liquid so it wouldn't collect in the compressor. The chamber can that I have seen is about the size, diameter, but shorter than a small frozen orange juice concentrate can.

 

[Tuesdak]

If you find you have no leaks but always charge the system once a year... As pointed out elsewhere the 2003-2007 trucks have a design defect where when the engine's cold 1) The fan isn't told to turn on for a time 2) The high pressure compressor cut out from the ECM doesn't work. The result is excessive high side pressures that pop the relief valve open dumping 1/2 the system charge about once a year. This is intermittent as "morning sickness" from the fan clutch spinning the fan at startup usually cools the condenser enough to not vent the system or if you get moving ram air cools the condenser. The rare time you start and idle the truck cold with the AC on and the fan isn't spinning from morning sickness is when the system is most likely to vent. The 450-500 PSI the system vents at is not easy on the compressor. Nether is the "slugging" from the low mount on the engine. They make a aftermarket De-slugger for other vehicles as GM and some others split the compressors in half and/or rip the tensioner clean off the engine from the low mount design. One reason OEM's low mount the compressor is for better oil return with R134a. (I have seen where alternate refrigerant doesn't stop the slugging so be careful as mentioned above when turning on the compressor.) Not a fan of dye, but, this showed me the leak from the relief painting everything behind the compressor including the oil filter... Of course after I replaced the evaporator just to be sure. I read where some have stuffed an electric fan in to run with the AC and only recharge every other year... View attachment 2014_4S_Deslugger_Brochure_indvl-pages.pdf

 

[Motorhead]

That "DE-Slugger" is a good idea. Too bad Dodge didn't incorporate that into the AC clutch circuit when they were producing our trucks.

 

[Thump]

After a few blow off situations in my 03's AC, I finally replaced everything but the evap core (was afraid to touch the dash anymore due to it falling apart). It proceeded to blow off, again.
Finally found that my fan clutch was weak. Not dead, just not operating properly. Replaced it and AC was actually cold out all vents for the first time in nearly a decade. You can find the check values on here somewhere. If even close to the out of spend range, spend the cash to replace it.