AC up and quit

[MAshley]

So took a drive yesterday and WOW no AC in a truck in rush hr traffic sucks.

So today I hooked up my scanner and pulled the following info.

Truck says it is 84F outside
With AC off pressure is 135 PSI
With AC ON pressure Jumps to 268 PSI

Again this is what the truck is seeing VIA its sensors VS actually hooking up AC gauges on the low and High side. Pretty sure it only has the 1 sensor.

But I get ZERO temp change out of the vents.

Looking under the truck I see a line of stuff on the coolant hose to the radiator, "Assuming it is clutch material" the clutch on the AC does engage and it spins with the belt, no idea if the RPM is exact or not, and it is a bit noisy.

Past history AC Clutch replaced, broken line to dryer and new dryer installed with recharge. Sense then no issues, been a few years.


SO here are my thoughts, the AC clutch is dying as seen with the material on the coolant hose right exactly in lin. Pump appears to be functional seeing as the pressure is changing but I suspect the clutch isn't engaging enough to pump enough fluid to cool....

So new pump and or new clutch? Looking for ideas I'm no expert.
AC brands?
Thanks everyone.

This happens to be on a 06 3500

 

[Wayne M.]

Hey.
You really have to diagnose this all the way through. Hook up the gauges and tell us what you see.
The last ‘06 I helped diagnose the ac on was a mega cab, and it had horrible Black Death in the system. Let’s hope that’s not the case with yours.
We need the same info you just gave, but real low side and high side numbers from a manifold gauge set.

 

[Dan_69GTX]

Yea, What Wayne said. There is a lot of info missing to properly diagnose.

So on top of that other things to help with an educated guess on where to start....
- What is the temp of the A/C line into and out of the condenser.
- What is the temp of the A/C line into and out of the evap?
- Did anyone ever use a sealer in the system. If so, game over....
- Any pics of the "line of stuff"?

Wayne said "Hook up the gauges and tell us what you see. " So...what that means is
- are the needles steady or bouncing
- What does the high side do in relation to the low side?
- What are the pressures when the compressor cuts off?
- What are the pressures when the compressor cuts in?
- etc

As an initial guess, based on what you gave us - if the high side goes up to 268 and no cooling at all,
- something failing internal to system plugging the orifice (compressor or accumulator)?
- bad blend doors

 

[MAshley]

OK Here are some numbers
After 24hrs resting which I know shouldn't make a difference.
Engine off, Same with engine on.

Outside temps today were 90+ reading were in the evening at it was about 75 outside.
Low 112
High 112

AC On
Low side 10
High 230

Gauges move fairly quickly, pretty smooth, no bouncing no spiking or changes. Both sides move in unison.
I only ran the truck for 5 min

So the pump runs but zero cold not even a hint of cold.
So if i'm reading the 134a charts right the low side should be 35-45 and the High side 150-170.
To me it sounds like there is a blockage maybe as the high side is epic high for the temp and the low side is low assuming it sucks down the low side to increase the high side, and the fluid isn't flowing.... But this is my speculation.


Black Death ... don't want that but interesting in knowning what it is.

No sealer to my knowledge, no AC in a can either. Last and only person to touch this was Midas about 4 years after I replaced, the dryer and a line that rubbed a hole in it. Line that goes to the dryer and the back of the compresor which I think is a tandem line to the consendor on the front of the truck

Would Love feedback on this, Thanks
David

 

[Wayne M.]

I think your charge is low, but that’s not your issue. The compressor is working. I think you may have a blend door issue in the dash.
Black Death? I it’s when the entire system turns black on the inside from a catastrophic failure. Worst case scenario. I don’t think you have that.
With those numbers, you should feel at least some cooling.

 

[Dan_69GTX]

I feel Wayne is correct! (He's good!)

Also if you would have given answers to...
- What is the temp of the A/C line into and out of the condenser.
And especially....
- What is the temp of the A/C line into and out of the evap?
Then that would confirm what he said.

I'm assuming the 90+ temp is not when you tried working on this?

The pressure charts are good when everything is working fine. Your high side could be higher than expected for several reasons. One would be the air flow over the condenser. Does the 06 have a separate fan motor for the condenser - don't remember, been a long time for that year range. Want the numbers lower, run water over the condenser and the pressures will drop amazingly fast. (not that this would help your problem - just an example of changing numbers).

Was the compressor cycling fast? (on for a bit, off for a bit, etc) or running normally (on for a while, off for a bit). Fast cycling is also an indicator of low refrigerant.

What speed was the blower motor on? Tests should be done with the fan speed on MAX.

When you figure out the main problem, please get the system serviced. The refrigerant in the system is what carries the oil. When you are low on refrigerant you do not have proper lubrication! Most A/C system failures occur due to this, NOT because of defective parts. Yes, the system has a low pressure cutout switch, but that is just like a low oil level cutout switch on a motor. By the time that happens you have created damage to the system.

 

[Dan_69GTX]

Sidenote.... Wayne - you answered at 3:59AM - don't you ever sleep!??

 

[Wayne M.]

Sidenote.... Wayne - you answered at 3:59AM - don't you ever sleep!??

Thanks for the kind words Dan, I was up getting ready for work. Early shift today.

 

[HHhuntitall]

... don't forget, with the truck just started, if fan clutch isn't engaged pulling air over condenser, head pressure will be very high, perhaps not indicating a blocked orifice. From what I'm reading, it sounds low on refrigant. Pop off valve on compressor, if equipped should be around 35-425psi. At 90* ambient temp, low side should read near 35psi, with high side in the area of 175-225psi, depending on air flow over condenser.

 

[Tuesdak]

With those numbers you are nearly out of refrigerent. All you are getting is hot foam into the evaporator. There is no low pressure cut out switch as Dodge uses a temp probe on the evaporator. Case in point the low side pressure is so low it should have tripped off any low side switch.

At this point do you have the tools to recover, vaccum, and charge the system by weight? Further do you have leak detection tools?

I have posted how these systems run the high side over 450 psig and dump 1 lb of refrigerent out of the safety relief valve due to no fan and no high side cut off. This may be how you system became undercharged, but, a leak detector should be run over the system.

So leak check system, fix if needed, recover, and charge by weight.

I would take a closer look at the compressor clutch for oil as your description of something being slung off the belt could be a leaking compressor shaft seal or something else asking for attention.

 

[Dan_69GTX]

Hmmm, JDoremire, I'd have to question you on the high and low cutoff. I'm NOT saying you are wrong!!! I don't have access anymore to OEM service manuals for the mid 2000 trucks. But, from memory.... There is a transducer on the line that monitors pressure of the high side. This is what the computer should use to command the fan and prevent over pressurization of the A/C system (turn off compressor). So, IF functioning correctly the system shouldn't blow out refrigerant. Yes, the temp probe in the evap - a PIA when intermittant. Chrysler has used those since the mid 90s. There isn't a low pressure cut out?? I don't recall there not being one, but I don't recall having to diagnose a problem with a low pressure cut out either - for this year in question.

So again - I'm NOT bashing you, I'm questioning so I can learn and, I don't have the reference material to look it up myself.

 

[petersonj]

I have posted how these systems run the high side over 450 psig and dump 1 lb of refrigerent out of the safety relief valve due to no fan and no high side cut off.

There is a transducer on the line that monitors pressure of the high side. This is what the computer should use to command the fan and prevent over pressurization of the A/C system (turn off compressor). So, IF functioning correctly the system shouldn't blow out refrigerant.

I have read many of JDoremire countless hours of documenting and troubleshooting with the help of some very knowledgeable people regarding the woes of the 2003 through 2007 AC problems on Dodge Cummins trucks. This problem he mentions above hardly ever happens and is not predictable. When it does happen the operator will probably never know that it happened.

I had the fortune of actually witnessing the event twice in a few minutes. The 2003 Dodge truck had been shut off for a couple of hours when I moved it in front of the shop to recover and recharge the refrigerant. If I recall ambient temperature was just under 80 degrees. I hooked up gauges and then re-started the truck. By the time I walked around to the front of the truck to read the gauges, the high pressure side was approaching 400 psi. I quickly shut off the truck and started scratching my head. I couldn't really see anything wrong, so I started the truck again. This time I got to the gauges a little faster, again the high pressure gauge was showing extremely high pressure - 350...400... and climbing - this time on the way back to shut off the engine, I noticed that the engine fan was not turning. So I started the truck a third time and immediately checked the engine fan which was now turning at an appropriate speed. The high pressure gauge was reading steady at less than 150 psi. The problem never resurfaced again. And yes, you would think that the PCM would have made sure that the engine fan was running during the high pressure condition, but it apparently did not receive the command. JDoremire probably can explain it better that I can, but I believe this is a design flaw in the software for control of the AC system for this generation of truck.

- John

 

[Tuesdak]

@Dan_69GTX I bleed GM orange and that is the system you are thinking of to have working high and low side cutouts. I have continued the work of others where 2003-2007 Dodge AC systems don't cut out on high 450 psig pressure. It should, but, doesn't. Pressure sensor is a glorified fan control. IMO I like the Dodge design better.

https://www.turbodieselregister.com...rams-ecm-defect-opening-the-ac-relief.258779/

 

[Wayne M.]

Charging by weight on a pulled down system is THE way to go- if you have the equipment available. Nowadays you almost can’t trust a shop to do the right thing.

 

[Dan_69GTX]

Good to know. Thanks! I was unaware of that flaw. Guess I'm not dead yet (always told the kids you stop learning when you are dead).

Years ago when the retrofit craze was happening from R-12 to R-134a I added a lot of high side cutouts when folks "demanded" that I retrofit their system. For the record I'd still rather not retrofit and just use R-12. Think I still have around 80 lbs left over.

Back then an identifier was a new thing - I used that a lot to prove someone didn't retrofit properly and that is why the system wasn't working correctly. Couple years ago I bought a new one and still use it to detect air that is causing problems. But don't do much work for other folks anymore. Just buy, fixup, and sell a few older cars. But I'll still work on the "classics" for folks since no one else around here will do R-12. One of the last ones was on a 64 Caddy - Nice car. Amazing how many A/C parts you can still get for these older cars.

So anyhow - thanks again for the education.

 

[Dan_69GTX]

Charging by weight on a pulled down system is THE way to go- if you have the equipment available. Nowadays you almost can’t trust a shop to do the right thing.

So true about shops. That is why I was VERY happy to find out the 2016 Rams were NOT using the new R1234yf refrigerant. I'd never recover the cost of new equipment.

When I had the water pump recall done (If it wasn't for warranty coverage that never would have happened), I saw that it appears the tech did a good job, so I found out who it was, bought a box of chocolates and brought it to him as a compliment. My goal is to ask for him anytime I need warranty work done and HOPEFULLY he'll remember the truck, chocolates, etc and do a better than average job - which would of course get him another box of chocolates. I know I'd try to jump over backwards for a box of chocolates, so hopefully he will too. (And if I tried that jump, I'd be in the hospital).

 

[Wayne M.]

Yes the new refrigerant poses issues, namely a huge investment.
The ‘17 ford supers still use 134 while the current Fusion hybrids use the new stuff. Bossmen haven’t sprung for the equipment yet. I hear R1234yf is flammable.

 

[Dan_69GTX]

Yea - "investment" is an understatement!

$70 per pound. Last year I spent $68 for 30lb cyls of R-134A (if you bought at least 4 at a time). I now it is more now but...
$5150 for the "automatic" R/R/R machine - https://www.tooltopia.com/robinair-ac1234-6.aspx
$130+ for the manifold gauges X2 if you want to do Hybrids too.
Hoses and fittings for the recovery only machine for "contaminated" refrigerant.
etc. etc. etc.

So, it is a no-go for me. But....the pressure/temperature characteristics are almost identical to R-134a. But it would be illegal to use R-134a instead of the new stuff that helps line the pockets of the manufacturer.

Also, my identifier doesn't do R-1234YF. The one that does - doesn't do R-12, which I do, so...I'd need another identifier.....sigh.
I have the RI-2004DX
https://refrigerantid.com/products/automotive-refrigerant-identifiers/