34 replies to this topic

[Keaton85]

Long story short, I had to replace the AC compressor bearings and then refill the system afterwards. Instead of taking it someplace to have it recharged I just did it myself. The only issue is that you can't do this in the winter time, the temp is to low for the compressor to kick on and stay on once it has been filled. Not knowing this I kept putting in freon!

Now I'm down in FL and found the system to be overcharged since the compressor was having a hard time. Once I took some out it started to function more normal. Nice ice cold AC.....

It work's but I still think it is overcharged and don't know how to get it to the correct amount if it's even possible. My current readings at 80 degrees is 35PSI low side and 250PSI high side.

Anyone have any info on how to get the correct amount of freon into the system? The reason I think it's overcharged is due to a little more strain on the system then normal since I get a idle drop once in a while and the AC compressor turns on and off at highway speed at 3K RPMs.

[Matty Moo]

35 at 80f is low. I usually roll with 42psi at 80f. I always add through my gauges, but carry a dial gauge/hose setup.

Just get a fill hose that has a small dial gauge on it. As long as you fill at 80f you won't overfill from a can as long as your adding gas and not liquid...so keep the can upright.

I've added at 55f using my TP chart and warming the can beforehand....but I always use my gauges. At 42 I'm blowing ice cold even at 95 with high humidity.

I have overfilled and froze up my evaporator but that was filling from the jug and not a small can.

[Keaton85]

I added pretty much all of it as a liquid...

The system works person from the stand point of blowing cold and never cuts out. the pump cycles but never stops blowing cold. I did some reading and read that you can't tell how much is in the system buy the pressure, only how much is in the system by the weight you used to put in.

I have a manifold gauge, so I wil recheck it tomorrow.

perfect not person***

[jschaefer7406]

Hello,

35 and 250 sounds fine. 250 on the high side is a little high, but that'll depend on humidity, whether or not the cooling fan was running, even how much crap is caught in the condenser .

If the system is overcharged, it won't put any more "strain" on the compressor, but will cause the evaporator to freeze up (as the low side pressure never gets low enough to cycle the compressor off). In any case, slightly undercharged is better than overcharged. As long as it's cooling well, I'd leave it where it's at .

Hope this helps,

Joe

[Keaton85]

Fan was running full out (rad. fan) and settled down to the 250-260 mark.

Before I "recovered" some though, I was at like 50 low side and 350 high side full fan! and the compressor was making noises once I let it run for a bit. Also it would cut out at getting up into the RPMS since the high side was sky rocketing up and hitting cut off.

I am just learning this, since I rather spend the money learning then give a shop money. I always just had the machine at work take over and do it all automatically but I wasn't at the shop this time around.

Thanks for the help though, I really want to get this AC stuff down as I have not needed to work on the systems much in my days.

[Matty Moo]

HVAC 101....never add liquid to the low side with the compressor running. Some people do it and shouldn't. Some people will throttle it in which is okay IF you know what you're doing.

I've never weighed in on a car, but there's room built in with the drier/receiver. I always just go by my gauges. Any residential shit always gets weighed in, or at least should.

[Keaton85]

Well, the compressor took the liquid just fine as far as I know.

As long as the AC works until I get back home and run the real AC machine, then I'm fine. But MAN with all new fluid the AC works fast and is perfectly cold.

[JRL]

Two hints
Puts the can(s) of freon in a bucket of luke warm water, then they go in quite easily.
Next a Gen 1 takes 1.65 lbs, so two full 12 oz. cans of R134 is so close... it's perfect

[burnout8488]

FWIW: My Gen 1 took seven cans at ~55ºF garage temp in order to operate properly. (Coming from a FULL vacuum evacuation) This got it to operate at 42-45psi low side. Using the specification of 1.65lbs, the pressure was so low it would cycle on and off constantly. As the RPM of the compressor rises, the low side pressure DROPS and this means I would never get any A/C while driving as the pressure would dip down into the low 20psi range.

No leaks whatsoever, and it never goes high enough to trip the high pressure switch.

[Matty Moo]

after reading your first post, did you evacuate the system before filling it?

[JRL]

FWIW: My Gen 1 took seven cans at ~55ºF garage temp in order to operate properly. (Coming from a FULL vacuum evacuation) This got it to operate at 42-45psi low side. Using the specification of 1.65lbs, the pressure was so low it would cycle on and off constantly. As the RPM of the compressor rises, the low side pressure DROPS and this means I would never get any A/C while driving as the pressure would dip down into the low 20psi range.

No leaks whatsoever, and it never goes high enough to trip the high pressure switch.

Guess what, something's very wrong or you're ungodly overfilled! (and as mentioned, you can't put it in cold)
They really do take approx. 2 cans only

[Keaton85]

after reading your first post, did you evacuate the system before filling it?

Down to 28-29 vac is the best I could get.

[Matty Moo]

Down to 28-29 vac is the best I could get.

Just wanted to make sure, not calling you an idiot of course.

[Keaton85]

Haha, I'm just going over the AC stuff so I'm pretty retarded at it...

You don't even want to know how many cans I used...

[scumcity14]

Guess what, something's very wrong or you're ungodly overfilled! (and as mentioned, you can't put it in cold)
They really do take approx. 2 cans only

For sure. I filled mine twice last year..once after I pulled the engine and once after doing the accumulator..Both times it took slightly less than 2 cans..how in the hell there are 7 cans in "burnout"s system I cannot imagine

Edited by scumcity14, 26 February 2012 - 10:49 PM.

[burnout8488]

Neither "can" I.

I really don't understand it one bit, unless the Wal-Mart 12oz cans are severely underrated...but I doubt it. (Interdynamics straight 134a)

What are your static pressures? (car off) Mine is approximate 80-90psi depending on temperature, and this seems to be normal based on what I've read on MVS. I really don't think mine is overfilled despite the gross amount of R134a it took, everything seems to check out fine.

Addendum: The compressor would function perfectly fine with two cans at idle, around 35psi... but while driving it would shut off. I need my A/C to work even when the temp dips into the 40's, since the car will fog up when it's raining. 2 cans might be enough for summer driving but in the winter it never was enough to keep the pressure high enough for me.

[Keaton85]

It is suppose to kick off in colder temps as it can't function. Pressure readings does not tell you how much is in the system at all.

The AC only kicks on and off in colder weather and should not stay on continuously.

[burnout8488]

What kind of car do you have? I'm 99% positive the Gen 1's A/C is not designed to cycle at any temp. You're right though, some vehicles do. My Subaru was designed to cycle on and off every 5-10 seconds, this was proper A/C operation.

I determined the cutoff temp for A/C is approx 38ºF in my car. So yes, at colder temps the A/C will not run. I'm starting to think I need a new compressor based on this thread's info, though. I'm probably having to add so many cans because the compressor isn't up to the task anymore.

[RobT5.]

Are you still in FL?

There are AC shops on every corner most will do free ac checks.
Just stay with them while they check it... most are shady.

[Keaton85]

Yeah, in Sarasota then going to Naples. How can they check how much though? I have my manifold gauges with me and everything has been looking ok so far. Had to take some out though since the compressor was freaking out.

I'm just trying to figure out if these is a way to test the system for overcharge. As PSI readings don't tell you how much is in the system.