civic_dork

A/C system isn't putting out very cold air on my 91 civic si, matter of fact only getting about a 8 degree drop from ambient weather. The compressor comes on, the refrigerant is flowing (as viewed through sightglass), and fan is pushing out air... though certainly not an amazing amount of air.

I hack jobbed the r134a conversion: repaired leak (it was rupture valve on compressor), drained as much oil as i could from the system but did not flush, did not replace drier, did not replace expansion valve, put system in vacuum to 30" and it held for more than 8 hours, put in about 11.5 ounces or r134a with 134 oil, etc.

I can't test the high side of the system, because i can't find a friggin adapter (like the one helm's keeps saying is 'commercially available), but the low side is within spec. So i'm thinking either compressor and/or expansion valve and/or receiver dryer is clogged bad screwed.

So a few questions:
1. Where can i fiund the 'comercially available' adapter for the high side?
2. What can i flush the system with and where do i buy it?
3. Is it difficult to replace expansion valve, anyone done it? Is there a 134 specifuic one?
4. Is my evaporator hosed (i think it may be because of lack of airflow)?
5. Anyone replaced a receiver/dryer, and where'd ya get it from... i forgot to order it from majestic and wondering if auto-zone one willl worjjk okay?
6. I really need that adapter for the high side! so i can test it correctly.
tia

ps: typos are due to my broiken middle finger.

And rippiung the a/c out isn't an option, i'm not a butcher.

eda6

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by civic_dork &raquo;</TD></TR><TR><TD CLASS="quote">I can't test the high side of the system, because i can't find a friggin adapter (like the one helm's keeps saying is 'commercially available), but the low side is within spec. So i'm thinking either compressor and/or expansion valve and/or receiver dryer is clogged bad screwed.</TD></TR></TABLE>

are the fans working? condenser coil clean? If the reciever is plugged the inlet will be hot and the outlet will be colder. when the the evap coil is plugged, airflow is decreased and it spends more time in the coil. You'll see a wider split with a dirty evap. Plus suction pressure would be low because the coil can't absorb heat.

to check your thermal expansion valve remove the bulb from the suction line and hold it in your hand. suction pressure should increase.

1. any refrigeration parts house should have it. You may need a mechanical contractors license to buy from them.
2.?
3.you'll see how simple it is when you're cleaning that evap coil.
4.as long as there's no leaks it's good to go.
5.never replaced one but it's just a dessicant stone that absorbs moisture from the liquid line. I
don't see anything wrong with a dryer from autozone.
6. i agree

what's spec for suction pressure? what's your suction pressure?

civic_dork

Thanks for the info and reply.

I'll see if i can pick up the high side adapter this week at a supply house (i have universal refrig. license, but not for cars... so we'll see).

Guess i'm just gonna have to pull the glove box out some time and take a look for myself... but i'm gonna waiikt untikl i (damn finger) can check the high side.

Spec is actually determined by high and low side pressures compared to atmospheric temperature and humidity, and the pressure enthalpy chart etc etc (the 134a conversion kit does some of the math for you, and shows a graph of acceptable). This method however i did not use. I used the guesstimation 'spec' and figured 40 psig was within this particular spec . Which now i'm thinking was incorrect, siunce r22 is higher than that and 134a runs higher than 22... so i think i was thinking backwards (new to a/c business).

Yes both fans come on, condenser is cleanish (i may squirt some coil cleaner on it just for giggles anyway). The suction line is cool... didn't put a thermo on it but guess it was about 65 degrees... and i expect it should be about 44 degrees.

So i threw another 5 oz of regrigerant into it today and got the discharge temp down to about 60 degrees, with the suction line feeling about 50ish or so... suction line @ 47 psig, so i'm now thinkiung i may still have a pinhole leak somewhere in the system... which i should be able to find. And while i have the glove box out i may pull the evap and clean it too, should it look dirty.

thanx again

eda6

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by civic_dork &raquo;</TD></TR><TR><TD CLASS="quote">Which now i'm thinking was incorrect, siunce r22 is higher than that and 134a runs higher than 22... so i think i was thinking backwards (new to a/c business).
</TD></TR></TABLE>

every refrigerant has a specific pressure at a given temperature. r-134 runs about half the pressure of r-22. i'm used to r-22 and i know that gage like the back of my hand. a 32 degree evap coil with r-22 will be about 60 psi. same coil temp using 134-a will be about 30 psi.

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by civic_dork &raquo;</TD></TR><TR><TD CLASS="quote">The suction line is cool... didn't put a thermo on it but guess it was about 65 degrees... and i expect it should be about 44 degrees.</TD></TR></TABLE>

evap temp should be 44 degrees but remember as the r134a passes through the coil it absorbs heat and it picks up more heat from the lines in the bay before it reaches the compressor. temp of suction line before compressor-evap coil temp is called superheat. you have 21 degress of superheat.

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by civic_dork &raquo;</TD></TR><TR><TD CLASS="quote">So i threw another 5 oz of regrigerant into it today and got the discharge temp down to about 60 degrees, with the suction line feeling about 50ish or so... suction line @ 47 psig, so i'm now thinkiung i may still have a pinhole leak somewhere in the system... which i should be able to find. And while i have the glove box out i may pull the evap and clean it too, should it look dirty.</TD></TR></TABLE>

good refrigeration practice is critical especially on smaller systems. what kind of hose are you using to charge the system? are you purging the lines before you connect to the access port?
if you don't purge the lines air is introduced to system and higher head pressure is the result. the condenser ends up with more load and the unrejected heat has nowhere to go except back to your evap coil.

the evap coil is unfiltered. your car is at least 15 years old. yes it's dirty. your coils will be more efficient after you clean them.

post up the high side pressure and ambient temp when you get the hi side adapter.