Dodge Cummins Diesel Forum banner
1 - 8 of 8 Posts

·
Registered
Joined
·
56 Posts
Discussion Starter · #1 ·
Alright, so last summer, I noticed the A/C was being odd. It would only work for the first 30mins of driving, then the compressor would stop engaging, therfore, no more cool air. I was just thinking it was low on refrigerant, and it having 300,000miles on the charge, I just thought a recharge would fix. I evacuated the system and got it recharged properly at my boss' shop, using the right tools. However, the system works the same. For 30mins of driving, the A/C is ice cold, but after that, the compressor stops engaging and the air becomes hot. It will work again once it sits for a while, like overnight, but it will repeat it. Any idea what this could be?
 

·
Mopar1973Man.Com
Joined
·
26,259 Posts
Condenser plugged up? Make sure you condenser is working good. What will happen is the high side pressure will get excessive and 450 PSO or so and the system will shut down because of excessive system pressure typically because of no way to dump heat properly. So make sure condenser, intercooler and radiator are flowing good air and the fan clutch is working good. If the fan isn't locking properly then again there isn't enough air flow to cool the system down high goes too high and shuts down.

Drive it around you neighborhood and when it shuts down find a garden hose and cool the condenser down if it kick back in then you know the high side protect was engaged because excessive freon heat.
 

·
Registered
Joined
·
272 Posts
I would check the air gap on the compressor clutch, make sure it's within specs & that should fix the problem.Hope this helps.
 

·
Registered
Joined
·
56 Posts
Discussion Starter · #4 ·
Condenser plugged up? Make sure you condenser is working good. What will happen is the high side pressure will get excessive and 450 PSO or so and the system will shut down because of excessive system pressure typically because of no way to dump heat properly. So make sure condenser, intercooler and radiator are flowing good air and the fan clutch is working good. If the fan isn't locking properly then again there isn't enough air flow to cool the system down high goes too high and shuts down.

Drive it around you neighborhood and when it shuts down find a garden hose and cool the condenser down if it kick back in then you know the high side protect was engaged because excessive freon heat.
No it's not plugged. I was doing high speeds when the A/C kicked off. I know the fan clutch is operating normally too.
 

·
Registered
Joined
·
403 Posts
The blockage could be internal, and preventing the high side from dumping pressure, acting like a second, more restrictive, expansion valve in the middle of the high side. It bleeds pressure too slowly and eventually the pressure gets high enough it cannot bleed off fast enough, it shuts down.

I'd put manifold gauges on it and see what it does from start til it stops working.
 
  • Like
Reactions: Mopar1973Man

·
Mopar1973Man.Com
Joined
·
26,259 Posts
Very valid too. Orifice tube and filter can be partially blocked. Still triggering the high side switch.
 

·
Registered
Joined
·
86 Posts
I just got done fixing mine, it took a new liquid line, compressor and condensor. I just bought this truck and thought it just needed evacuated and filled too. I tried and the high side went to 450 plus but the low side went to a vacuuum! It was plugged up with drier pellets at the tube in the liquid line. I took it all apart, cleaned the evap so i wouldnt have to take it out (no time) and flushed the other lines. Charged her up and im at 42 degrees out the vents, but i would check the gap at the clutch before all that work.
 

·
Registered
Joined
·
9 Posts
I'm having the same issue. Replaced the orifice tube and recharged but still the same thing. Had the compressor tested and it seems to be fine. I did find that my thermostat was stuck open, replaced that and it seemed to help some...weird huh? Still searching...
 
1 - 8 of 8 Posts
Top