My air isnt getting very cold anymore. Is it normal for a 134a converted system to look like smoke going through the sight glass on the receiver? I think the compressor was disconnected for a few hours at some point last month when i had my car worked on. Im thinking maybe theres some moisture or other contaminant in my system now.

what should i do? and can i fix it myself?

 

did you racharge it after hooked the compressor back up? how?

 

Moisture in the A/C system is very bad.

What is the MM&Y of the car?

You say "a 134a converted system" I assume you mean retrofitted from the R12 system, is that correct?

If so, who did the retrofit and what kind of retrofit was done?
Back yard special, [Red Tek, Duracool] so sad.
Basic, change service ports.
Minimum, flush, replace receiver/dryer, O rings and service ports.
Proper, flush, replace condensor, reciver/dryer, O rings and service ports.

How long was the system on a vacuum pump before it was recharged, [very important to remove moisture from system].

My guess is the receiver was not changed as the retrofit reciver would not have the sight glass, [not used in 134a systems] meaning system is contaminated with R12 at the very least, if Red Tek or Duracool, [or one of the other back yard "refrigerants"] was used then the system is also contaminated with hydrocarbons, [propane] and sealers, not at all good. 94

 

thnx for the reply.

its a 1990 crx with a sanden compressor. Yes, the car was originally r12 and now 134a. I just bought the receiver and expansion valve from advanced auto parts! i didnt know there was a retrofit receiver. after i installed the parts I went to a professional that i trust to have the system charged and swap the two service ports. He said it was on the pump for an hour.

The system was already flushed and filled with 134a before i put the the new receiver in.

It was blowing cold until i got a motor swap. It was cold right after, but slowly has been losing its chill. I have no idea if it was even pumped at all when the compressor was reinstalled. Visually it doesnt look like theres any oil coming out any of the connections. Im not sure which type of freon was used, but i assume whatever it was was reused when the compressor was reinstalled.

 

sound like you have a leak. your gonna have to recharge it again and this time install ac dye so you can locate the leak

 

Ditto the above^^^, it sounds like you have a leak.

It also sounds like the retrofit was done OK, you can still use the R12 reciver, [W/sight glass] as long as you replace it, 45 min. is the minimum time on a pump, 1hr is what we always do, so it is unlikely that there is R12 or moisture contamination in the system, and if you used someone you trust it do the recharge it is unlikely that they used anything but R134a.
I would go back to the pro you trust and have him put a set of gauges on and see what the charge is.

Unfortunately it is not something you can check yourself and tell, other then if it is empty, remove a service port cap and press the schrader valve real quick.

A compressor that "short cycles", [turns on off, on off, on off] is a sign of a low charge, and not turning on at all could mean a really low charge, and progressively less cooling is a sure sign of a leak.

How long it takes to go from normal cooling, [working A/C] to no cooling, [non working A/C] will depend on the size of the leak.

We hear this every day, "my A/C system isn't working as good as it used to" or "it's cold but not as cold as it used to be" or "My air isnt getting very cold anymore, 99% of the time the A/C is not working at all.
Have you checked to see if the compressor is turning on at all?
Check that^^^ and press a schrader valve.
Let me know what you find. 94

BTW, you said this happened after the engine swap, a common mistake is not replacing "O" rings at fittings that have been opened because they "looked good" this almost always results is leaks at the fitting, A/C "O" rings are one time use items, and should be replaced every time a fitting is opened.

 

The ac is working. Its just not as cold as it was before. The compressor does turn on, and one of the lines i think the low pressure one is cool to the touch. There is refrigerant in the system.

My main questions are:

Can you actually tell anything from the sight glass anymore once the car is converted?
mine shows a steady stream of grey/white gas.

Would moisture or contamination cause the ac to lose its chill over a few weeks? or will only a leak cause this in such a short amount of time?

 

Sightglasses are basically useless as far as any real a/c diagnostics go.
Moisture or old refrigerant would not cause the system to decrease in performance over time.
There could be a leak. Most likely. = something you cant check
If your weather is like ours is right now. Cool mornings/hotday/ cold night. Maybe you have changed the postion of the heater valve1---2 your heater cable is out of adjustment the heater valve is not closing all the way. = something you can check.

 

Ditto the above^^^, make sure the heater valve is closing, pinch off the line to make sure.

As mentioned, the sight glass will tell you nothing on a R134a system, [that's why the retrofit reciver does not have one.

I disagree that moisture will not cause low output, the absolute worst thing you can have is moisture in the system.

Poor A/C operation can be caused by a number of things, the main one being low refrigerant, too much is even worse, [poor cooling and high head pressures, the second most common cause is poor air flow through condenser, check for obstructions.

Make sure the rad fan also comes on when condenser fan turns on, both need to be running for proper airflow. 94

 

thanks thats exactly the info i was looking for.

both the fans come on. I did further inspecting, one of the connections that come out of the condenser looks oily/grimy. It was hard to see until i got under the car.

I read in another post that the vacuum pumps that hook up the compressors arent very good so Im just going to take my car back to the guy who charged it the first time.

 

fcm you are baaaaad!

good info

 

Oily residue around fitting indicate a leak, [bad "O" ring] when refrigerant leaks out it evaporates instantly but the system oil, [Pag oil or Ester oil] will leave a stain around the leak.

Not sure what the post about "not very good" vacuum pumps is about. 94

 

well I just got back from getting my ac checked out. the estimate said:

condensor is bad (leak at fitting),
Left cooling fan bad (no room for heat shield),
Expansion Valve erratic,
Drier
compressor is bad (will not pump properly below 2000rpm)

how could all this stuff break in three weeks, during which time ive used the ac like 8 times. I just changed the drier and expansion valve 3 months ago.

everything was running smoothly before 3weeks ago.

Also the compressor seems like it is running more rough at idle than when i brought it in.

 

When you did the "retrofit" to 134a, did you put oil into the system?
No or low system oil would cause all the above problems, except the leak. 94

 

Also when a compressor goes bad it, the oil that is in the system will carry all the metal flakes, which will clog up the expansion valve/orifice tube and condensor and any other small hole it encounters. The drier should be replaced anytime the system is opened, (technically speaking you can sometimes get by without it). That sucks for ya, AC **** is expensive to replace, especially the compressor

 

yes the system was oiled properly three months ago when the retrofit was done. however, like i said i have no idea what happened to the system three weeks ago during the swap.

So do you guys think everything listed needs to be replaced now? Or can I just fix the leak, vacuum, and oil/recharge properly?

The entire reason i went with a b-series is so i could keep my ac, and now it looks like close to 1k dollars to keep it working, when it worked perfect for three months prior, already. Im so sad right now, I wish I could take back the last three weeks and keep all my new car money. I love this car, but its not loving me back.

Also, thx everyone for your advice i appreciate it.

 

I find it hard to believe all those things went bad at the same time also.

I would like to know how the shop came to those conclusions and why???

EG;
"condensor is bad (leak at fitting)" why would you need to replace the condensor if it's the fitting that is leaking, a new "O" ring should be all that is needed, unless the fitting is damaged somehow.

" Left cooling fan bad (no room for heat shield)" is the fan damaged, not turning on?

"Expansion Valve erratic" possibly, but why?
When you replaced it did you make sure the capillary tube was mounted to the suction line and wrapped with cork tape properly?

"Drier" what about it?

"compressor is bad (will not pump properly below 2000rpm" a low charge would possible account for that as would a defective or improperly installed expansion valve.

Question,
How long was the car in the shop, what did it cost you for the estimate?94

 

the fitting looks fine to me, but i am no expert.

cooling fan does turn on.

expansion valve is mounted to the pipe properly, i just reused some of that black tar stuff. I didnt know what it was. most of it was crumbly so i just packed it all around the tube.

no idea whats wrong with the dryer.

it was there for a couple hours, i left so i dont know how long they worked on it. it was like 50 bucks for the estimate. and the air was cold again when i left, i think bc it was fully charged. but at idle you could hear my compressor louder than before.

Update: So i got someone to put some guages on the system while i was watching. the low pressure side went up to 62psi when the ac was on for like 10 minutes. It went up to 60 and then stayed there pretty much. it didnt look like it was losing any pressure. then when i turned the ac off it went up past 100 psi. I think the guy who gave me the estimate might have over charged the system. Also the ambient temperature inside the garage was about 90° if that makes a difference.

 

^^^
the low side was 62 while operating then when turned off went to 100?

what was the high side while operating/ turned off?

let me guess, the high side was 100 while turned off right?

 

somethings not right the average low side psi should be around 20-30 in those conditions what about humidity.
sounds like a lot of oil in the system.
what was the high side like ?

 

High side was 160 during idle, I didnt watch it after I turned the ac off.

20-30 is normal at idle for low side? what should the high side be?

 

As mentioned, low side @ 62psi when A/C on is way too high, should be lower then 30psi.
High side when A/C on will depend on cycle switch, but 160psi is OK.

Air flow, [condensor/rad fans] seems OK as high side is well below 200psi.

An over-charge would result in poor cooling and high high side pressure.

This sounds like a blockage problem, the first thing I would check is the expansion valve, as problems arose after expansion valve was replaced.

Try this, turn system on, let run for a few min. then grab both the lines going to the evaporator, let me know if they are hot or cold. 94

 

Also if you can give the line temps also high side pressure readings are crutial also. Their is so many variables that are not beign told. Restriction would increase high pressure and low side will vary but high oil content will bump low side temp. Over charged system will still show about normal readings and the high will be high.

 

Like i said, the high pressure side was 160. I dont know how to measure the line temps. All I can do is tell you the Low pressure line is cold going into the evaporator and hot coming out. The ac does currently blow semi-cold after the estimate, but im afraid to use it, as i dont want break anything worse.

This is the order things happened in, in case there is confusion.

AC did not work for many years.

I had the system retrofitted flushed and charged. It didnt work so i replaced the compressor, drier, and expansion valve.

Got the system vacuumed and charged, presto everything is cold.

3 months pass with everything working.

Motor swap. Get the car back. Air is not as cold, but still good enough. Air loses its chill slowly over three week period.

Got estimate.

Hooked up gauges and started the ac and saw the low line psi at 62.

 

At this point I would recover the system, flush it and recharge with proper amount of system oil and the correct amount of R134a, [80% of R12 charge].

The fitting at the condenser that is leaking will need a new "O" ring for sure, I would also do a nitrogen check before charging the system to make sure it will hold at least 200psi for 1hr, overnight would be better. 94