want to get my ac working...

[Workin' Rig]

It wont blow cold air. The line running into the top of the condensor is hot...compressors running but i get no drip and no cold air??? Had it converted and charged...

Any ideas?

Also i cant seem to find an evaporator anywhere...the dryers are cheap and readily availiable. Any idea where to score a evaporator?

 

[dustybumpers]

the other line should be cold, or sweating. Have you put a set of guages on it yet?

Could be that someone has jumped the low pressure switch, and the compresser is running without a charge

 

[Workin' Rig]

No i havent put gauges on it..,but the compressor didnt run before i had it charged..,i kno crap about ac....just want it to work

 

[5.0Flareside]

Check and make sure the compressor is kicking on.. And in what way was it charged?

If not done properly it will blow hot..


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[Workin' Rig]

I had a shop do it so i assume it was done correctly....whats the psi rating to fill it to?

 

[SuperCab]

Iirc 40-50 psi on the low pressure fitting with the compressor running.

 

[5.0Flareside]

More like 35-50ish depending on ambient air temperature read off the low side..


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[5.0Flareside]

But you don't fill to a psi.. You fill to a weight (I.E. 1.32kg)

And by putting correct weight in, the pressure will be in the right range.

By working at valvoline I've see. Several shops do ac work and recharge the system at too high of weight of freon and it blow hot..

To much freon=blow hot. Also blown seals etc..


And that canned freon shit at parts stores, it over pressurizes systems. Cause if the system doesn't cool it's been leaking or has evaporated off. So oxygen has taken its place.. Adding more freon puts to much stuff in the system..

And it'll blow cold a couple days then got..



You have to check for leaks, evacuate system, change high and low valves, recharge at correct weight check for leaks again..



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[Fellro]

The way you make it sound, there is no way to service a/c short of total evac... Not necessarily true. Sure, that is the most accurate way, as the charge is based on volume, which is measured by weight. However, you can also measure the volume of a gas by the pressure it exerts on a closed system surface. That is why it is most certainly possible to properly service a system without going to those lengths. R-134 is a smaller molecule than the R-12 was, so over time, refrigerant will be lost to simple diffusion through the hoses. There does not have to be a verified leak to allow it to seep down. The ONLY way oxygen can get into the system is if it is open, which can happen with hooking up the gauges yes, but not enough to be an issue. Just because the system is down on charge does not guarantee a serviceable leak, and most definitely does not guarantee oxygen got in. If you blow a seal to the point of complete failure, or blow a hose, then it is possible to get outside air in. Atmospheric pressure will not override the internal pressure of the system.

Over filling the system will trip the high pressure switch. THAT is more why it runs hot, however, the whole reason behind the cooling effect is that the pressure has to be different between the high side and low side, so in the event there is no high pressure switch, the system could theoretically get to the point of near equalizing the pressure, and no cooling effect will take place. However, in reality, if it is that much over filled, hoses/seals/compressors tend to blow. If it were to be too high, the high side would become liquid, and liquid does not like being compressed.

It is most definitely possible to add charge properly without having to start from total empty. That is only necessary if the system needs to be serviced. I have had many systems that got low on charge over the years or from extended sitting that maintain charge for well over a year, not just a few days. The only times I have had any issues is if there is a bonafide leak, which means it would be starting from nothing. (My old man will throw a can in and within days be gone, I will not do that.) If a system is completely down, then a vac test will find a leak big enough to lose charge within days. Then a scale could be used to fill. The pressures will guide you to the right charge. The problem with the cans is not so much that they over charge, it is that the operator puts too much in. They are no different than starting from nothing, in that it still has to be metered, it is just a pressure check instead of a weight check. Otherwise, how would you be able to test for proper charge without taking it all the way down and weighing it? BOTH are guidelines, not absolutes.

If you had a shop service it, take it back to them and have them explain why their work is not doing the job. Did it cool at first after picking it up? If not, you should have gone right back. It could be that the orifice tube/ expansion valve is plugged. This would let it keep the compressor running, yet not effectively cool. If a conversion is not done properly, this can happen.Otherwise, it is possible it leaked down enough to keep the low switch tripped to keep the compressor running, but not enough to get the required change in pressure after the expansion valve.

 

[Workin' Rig]

Wow good response.

I had the shop charge it. It didnt blow cold and i figured there was another issue besides having no charge.

Where is the oriface tube located on these trucks? I may just have the whole system evacuated and begin replacing shit.

Also does anyone know where to get a evaporator?

 

[fatherdoug]

It wont blow cold air. The line running into the top of the condensor is hot...compressors running but i get no drip and no cold air??? Had it converted and charged...

Any ideas?

Also i cant seem to find an evaporator anywhere...the dryers are cheap and readily availiable. Any idea where to score a evaporator?

Blue Oval Truck Parts sells them but are NOT cheap.

http://www.blueovaltruckparts.com/i-4885-0-5689-Evaporator-Core---For-models-w--factory-AC.aspx

 

[dustybumpers]

Check for leaks before you buy anything.

I had a shop tell my wife she needed a new evaporator. Turns out the door to the heater core had come off it's hinges, and was putting heat on it. New door and actuator, and it cooled like a brand new one.

 

[Fellro]

Definitely before replacing parts, proper testing and checking needs to be done. The problem can be pinpointed without a teardown. It is no different than dealing with an engine issue, start changing a lot of things, and it is hard to tell what the problem actually is. Proper testing and checking is needed to figure out the issue.