A/C Cooling Issue

[Wildcard]

sounds like a bad thermostat. Your temp dial should have a sensor in the coil. It should shut off the compressor via coil temp.

[kozakvod]

(04-17-2020 )Lonestar10 Wrote:  probably need to make sure the hot water to the heater core is off. might help soon as i put a hose clamp vise grip on one of the hoses to heater core last year my life was never the same as far as how good the truck cooled down on a real humid day i could be throwing fog out the vents it was so cold.

Yep. Did that too. Hot water off, or on, nothing changed. Dang thing will do what it does regardless of what I do. If I can figure out how to make money idling, I'll stay cool as a cucumber! :)

From the Evap all the way back to the compressor the low pressure line is freezing. A buddy told me the TXV sounds bad OR the Evap isnt free flowing enough (dirty), OR both. So I'm going to clean to Evap and replace AGAIN the TXV and see what I get.

[kozakvod]

(04-17-2020 )Wildcard Wrote:  sounds like a bad thermostat. Your temp dial should have a sensor in the coil. It should shut off the compressor via coil temp.

Copy that Wildcard, another item to check.

[Waterloo]

I would put money on the evaporator, they do not last forever. Change the cabin filter at every oil change, and when you fuel, pop the hood and make sure the drains for the condensation are clear. The evaporator is not difficult to change, just takes some time digging everything out. If I were in there, I would also replace the heater core.

http://www.truckersac.com

[kozakvod]

(04-17-2020 )Waterloo Wrote:  I would put money on the evaporator, they do not last forever. Change the cabin filter at every oil change, and when you fuel, pop the hood and make sure the drains for the condensation are clear. The evaporator is not difficult to change, just takes some time digging everything out. If I were in there, I would also replace the heater core.

http://www.truckersac.com

Waterloo you're probably right about the evap. What keeps racking my brain is the decrease in air flow. The only thing that would cause that would be freezing of the evap. as best as I can tell. As my buddy told me that normally a bad TXV will cause line freeze back to the compressor, but I contend it's originating at the evap and freezing back through the TXV to the compressor.

Well, I'm going to walk into this again with the idea that a full replacement (as you speculate and suggest) of the evap is probably going to happen and I'm going to clean it first and see if that makes a difference or not.

[Lonestar10]

I would have the system drained and refilled to proper lbs, and also replace any evap temp sensors replaced since it seems like its freezing also would try to wash the evap out to remove any possible contaminants that could be absorbing any moisture

[SquareOne]

^^^ ---- to add to that, anyone who is familiar with reading A/C gauges should be able to diagnose what is going on. The high/low pressures will give you what you need to know in order to come to a conclusion about freon level, health of the compressor, expansion valve (or orifice tube if that's what you have), clutch fan, condensor...etc...

[kozakvod]

(04-18-2020 )Lonestar10 Wrote:  I would have the system drained and refilled to proper lbs, and also replace any evap temp sensors replaced since it seems like its freezing also would try to wash the evap out to remove any possible contaminants that could be absorbing any moisture

I actually did replace both sensors, but it was done as a thought of one or both being bad and or being the cause of the problem. Ultimately neither had an effect on what it was doing. Why it only will do this at highway speed is the real pickle.

I do agree with you. I think the thing to do is to have it drained then set it back in my yard and pull the Evap. But most likely I will simply replace it instead of cleaning. I don't know, but my guess is that its the original Evap from factory and at 580k it's probably ready. We bought the truck in Nov of 17 so we didn't even really use the AC until the following summer and it had the problem then. So I have no idea if it just started or existed in summers past.

[kozakvod]

(04-18-2020 )SquareOne Wrote:  ^^^ ---- to add to that, anyone who is familiar with reading A/C gauges should be able to diagnose what is going on. The high/low pressures will give you what you need to know in order to come to a conclusion about freon level, health of the compressor, expansion valve (or orifice tube if that's what you have), clutch fan, condensor...etc...

You'd think that living in TX finding a good AC guy would be easy...surprisingly difficult. However, there are a LOT of shops that can screw it up. And yes I do agree with what you said.