AC lines freeze up

SamCarroll

SamCarroll

Faux Runner
Staff member
Jan 25, 2011
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Northern California
So i think i found why my air doesnt blow after 30 minutes after being on. my lines from the compressor back to the condensor completely ice up. Now ive done some reading and have found it could mean im low on freon, low pressure hose sensor of some sort is bad or my orifice tube is clogged?

What is the best way to go about this? Ive never had AC issues before and really want this fixed.
 
well you have a few options.

first you could go to a auto parts store, and buy the AC hookup with the guages and see what your pressure is. (not sure if this applies in cali)

Secondly, i have a similar issue with my OBS, its not that the lines freeze up as much as the clutch is junk on my fan.

Third, There may be moisture in the system allowing it to freeze in the lines.

Ill text my buddy who is a certified AC guy and see what he says.
 
First off, how is your air flow? If your evaporator is clogged up with dirt and crap it can cause this, a sign would be poor air flow out of the vents.

Second, after checking to see that it is clean, check the condenser behind the grill, make sure it isn't obstructed/full of dirt, bugs, paint, etc.

After you have done those simple checks, now go put some gauges on it, real gauges, not that vhatozone on a can crap with the little green "good" range that doesn't mean jack.

An obstruction in the orifice tube is possible, if this is the case it must be evacuated, replaced, a vacuum pulled and recharged.

Low on refrigerant (hint, it's not Freon) could be a possibility, again, won't know until you put gauges on it, don't just go around recharging it, find the leak first, AC guys will have a leak detector machine, if that doesn't find it they can put dye in the system and look for it. Usually they aren't too difficult to find on these trucks, the o-rings at the compressor block, pressure switches, etc are common places to look.
 
Also should have mentioned, a lot of city driving with a dying fan clutch, or a weak blower motor can cause the same results.
 
Ginger said:
well you have a few options.

first you could go to a auto parts store, and buy the AC hookup with the guages and see what your pressure is. (not sure if this applies in cali)

Secondly, i have a similar issue with my OBS, its not that the lines freeze up as much as the clutch is junk on my fan.

Third, There may be moisture in the system allowing it to freeze in the lines.

Ill text my buddy who is a certified AC guy and see what he says.
Click to expand...
I have a friend whos got gauges and will look at it monday, hes going to see if he can bypass a low pressure piece and see if it works still, then we know where to tackle.

GCncsuHD said:
First off, how is your air flow? If your evaporator is clogged up with dirt and crap it can cause this, a sign would be poor air flow out of the vents.

Second, after checking to see that it is clean, check the condenser behind the grill, make sure it isn't obstructed/full of dirt, bugs, paint, etc.

After you have done those simple checks, now go put some gauges on it, real gauges, not that vhatozone on a can crap with the little green "good" range that doesn't mean jack.

An obstruction in the orifice tube is possible, if this is the case it must be evacuated, replaced, a vacuum pulled and recharged.

Low on refrigerant (hint, it's not Freon) could be a possibility, again, won't know until you put gauges on it, don't just go around recharging it, find the leak first, AC guys will have a leak detector machine, if that doesn't find it they can put dye in the system and look for it. Usually they aren't too difficult to find on these trucks, the o-rings at the compressor block, pressure switches, etc are common places to look.
Click to expand...
Im pretty sure the condensor is brand new, or newer. Not original. There very well maybe low refrigerant. That will also be checked on Monday.

HankScorpio said:
Agree with above clean the evaporator and condensor and try again
Click to expand...

Might try to clean it or double check it.
 
SamCarroll said:
I have a friend whos got gauges and will look at it monday, hes going to see if he can bypass a low pressure piece and see if it works still, then we know where to tackle.


Im pretty sure the condensor is brand new, or newer. Not original. There very well maybe low refrigerant. That will also be checked on Monday.



Might try to clean it or double check it.
Click to expand...


well if its getting cold enough to freeze i imagine its not from being dirty . a clog is possible but would not be me first suspect you said you believe its a new condenser right, do you know who or why it was replaced? was it a shop that refilled it or the previous owner? alot of people dont understand that our cars ac needs a vacuum then filled just atmospheric pressure is 14.6 psi so that = a lot of extra fluid that is in a system that is only intended to be a refrigerant. Also what year is your truck? might be r12 (expensive) not r134a ( cheap) most commonly when people try to fix their own ac they dont charge it properly, either dont pull a vacuum, overfill, or under-fill to spec. inside a vacuum water will boil until it freezes you can do repairs yourself with proper tools. they are not that expensive,
pressure chart for r12 and 134a
http://www.ackits.com/aacf/ptchart.cfm

got both of these on sale gauges were 45 buck and vacuum was 90 bucks.
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so we recharged it, it was a tad low. It still ices up but doesnt freeze.

Still trying to figure out my blend doors. It keeps going off after awhile.
 
Ok now I think my AC is on full time. On cool with ac in the off position it blows REALLY cold air like as if ac is on. Eventually the air felt like it was freezing up and stopped then I turned to hot and blasted it. About 3 min and it came back. So SOMETHING is freezing up and making it just blow into the box and not out the vent.
 
Ginger said:
maybe the compressor is stuck on? thats the only way you should be cycling the air to be cold
Click to expand...

its just far too cold to be just cool air from outside. Shit was cold and its hot out. something just isnt adding up. It would also explain why i dump a shit ton of water.
 
Do you have the air on Recirc? I can't recall on OBS, but NBS, recirculate cycles the compressor as well.
 
GCncsuHD said:
Why not.... once you get it cooled down a bit using A/C-fresh air, it will make the system run much more efficiently on A/C-Recirc, use less fuel, cycle less, etc, and less likely to freeze up.
Click to expand...

:hmm: I just honestly never use it. Probably will now but i just wish i could figure this shit out. Not sure whats going on with it but its confusing. Im debating just taking to shop i know and say fix it.
 
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