any a/c gurus in here??

I've got a honda and a ford I'm doing the a/c on and both are giving me some problems.

the honda is a 93 civic, I've got a leak on that I cant find. how can I pressurize the system to check for leaks using soapy water??

I've got a harbor freight manifold gauge set and the electric 2.5cfm vac pump. no nitrogen charging system lol.

on the ford...its a 95 mustang gt. the system pulled -30hg just fine and took the oil/r134a charge just fine up to the specifications. only problem is the compressor wont cycle off. it just stays on constantly (did this for 10 minutes straight) and the engine started getting kinda hot. I know this will only get worse the hotter it gets. temperature at time of fill was 80*F and after hitting spec, the low side was reading 42-45psi and the air was blowing nice and cold.

cant figure out why on either.

 

Quick idea on the Mustang....I would guess the cycling switch may be stuck.
It is the switch on top of the drier bottle.

You could take it off and test it. If I remember it should be open without any freon pressure on it. I think too it is supposed to open around the mid 40psi range.
You can unscrew/take it off, there is a shrader valve under it.

As far as the Civic, any black, greasy stuff on any of the lines?? Usually a good sign of a freon leak.
Not to sure on the idea of soapy water....My thoughts are that it would take a pretty large leak to show "bubbling"...

Just some ideas,
good luck,
IZ

 

well the system on the civic has been off in a box for a few years so there's no actual grease buildup from where pag oil would have leaked if thats what you mean.

how can I test the switch itself on the mustang??

like if its stuck and I take it off and leave it hooked up to the wires and the compressor is still going then I can assume its bad or something??

I mean, when I was first charging the system and it was beginning to build pressure, it would cycle on/off really quickly and then as more gas was added it would lengthen its cycle on before switching off and then once I built up 40psi it just sorta stayed on...though its blowing nice and cold lol.

I'm thinking I'll just replace ALL the o-rings on the civic system and recheck after I do this and check all the connections. its probably a loose connection or bad o-rings at this point.

 

For the civic, best thing to do is inject dye into the system and use a black light to see where the dye comes out. To get pressure into the system, you have to recharge the system with freon. Sometimes if the leak is bad enough, you can hear it hissing out, if not, the dye will show you where its coming from.

X2 on the cycling switch. What is your high side pressure? Might be the pressure switch that is bad if your AC system has one...

 

How are you determining your refrigerant charge, [how much your putting in]?

Without nitrogen the only way to spot a leak is either with dye, the oil residue at the leak, or a leak detector, [not cheap].

If you did not use new O rings when you reinstalled the system in the Civic then I would be willing to bet it is at an O ring where the leak is.
Also, did you retrofit the Civic to R134A?

For the Ford I have the same question, how did you determine the refrigerant charge?
Was that 42-45psi on the low side when when compressor was on?
What was the high side pressure, [compressor running]?

If you remove the pressure/cycling switch on the Ford, [still plugged in] and compressor continues to run the switch is bad, [low pressure] and needs to be replaces, the switch is a high/low switch, cycling is done when pressure exceeds the switches upper limit.

I will check at work... http://airwolfeautoair.com/ later on charge amounts and pressure/cycle switch for the Ford. 94

 

the sticker on the core support on the mustang stated max refrigerant was 2lb-2oz = 34oz

I added a 14oz can that had 11oz in it + 2.5oz oil +.5 leak detector, and 1 full 12oz can of fluid and just about all of another 12oz can of fluid. total added was approximately 34-35oz I would say by the weight still in the last can as if I added all three cans complete would have been 38oz. not exact but it worked for me and the air blew **** cold.

I'll give that pressure switch thing a try this afternoon.

42-45psi was on the low pressure side and the high pressure was reading 210psi I think if I remember correctly. I can check again this afternoon and verify if need be.

oh yeah, until I put the caps back on the line ports after I shut off the car, they were hissing a little but after I tightened down the caps, it was all quiet. is this a sign I have too much pressure in the system and its forcing past the port ball plugs??

 

oh and as for the 93 civic...I have and havent swapped it over to r134a lol.

its actually a hybrid system. it uses the evap housing and some of the lines from the 93 and uses a 94-00 compressor and condensor and drier.

I had a 95 I was parting out that had good a/c on it so I kept all the stuff from it until I realized the evap housing was different on 94-95 due to the airbags.

I tried using the 95 compressor on the 93 only to realize the lines wouldnt match up as one was for r12 and one was for r134a.

then I just sat back and looked. sure enough, if I swapped out the condensor as well, THEN the hard line that breaks under the core support could be spliced using the newer stuff right there, and the outlet to the evap from the condensor (the big one that has the rubber bend on the end) would also bolt up universally.

I blew out the lines and evap from the 93 and filled with some of that conversion oil and then blew them out again. then just filled regularly and it worked nice and cold for 2 years before I took it off for a turbo install.

found a greddy setup cheap and tossed that on so I could put a/c back on as its hot as ***** here in the south and now I'm having the leak problems. I'm thinking the old r12 o-rings that I left on the evap housing back in the day must have degraded from the r134a oil or something...

 

At 38oz you are over-charged, a .5oz+/- is OK, 4oz is too much, the clutch cycling switch is 39 on/22 off, at 42-45psi it will never shut off.

The service port valves should be good to 600psi, if they are leaking, replace them, the cap is a dust cap, they they will not hold a leak, just slow it down.

Also a head pressure, [high side] of over 200 psi is too high, 200psi should be the max, is the condensor fan turning on, how is the air flow? 94

 

LOL, that is pretty much a R134A retrofit, when we do a retrofit we change the dryer, service ports, oriface tube if used and do a flush, then do a 90% refrigerant charge, works great.

The evaporator does not have to be changed.

Change the O rings and you should be OK. 94

 

well why was the temp chart also saying that @ 80*F the low side should be showing 40-50psi? I'm just trying to understand is all.

and man, I dont want to replace that big manifold line...thats the expensive one lol. also, I checked the pressure switch by taking it off and hooking it up and the compressor wouldnt turn on. put it back on assuming its good as a result and now the compressor cycles. lol. I hate learning troubleshooting on new systems.

cant wait to see the blunders I make learning to paint haha.

replaced all the o-rings on the civic and there was one that was torn. held -30hg for 2 hours and charged it and its ice cold wooo.

 

Is the 40-50 psi with the compressor running? 94

 

yep.

also, the system leaked down through those ports.

dammit I dont wanna replace that stupid $$ line...

 

change the shraeder valve in the ports.

 

there isnt one, there's these ball looking things. they are definitely not shraeder valves like in tires though if thats what you mean.

actually after looking at the ports again real quick, they arent even *****. its like a piece of metal that must be spring loaded on the backside to keep it pressed up against the inside of the port opening...weird.

 

They usually are replaceable however. And the caps on them are not dust caps as was stated earlier. All AC sysytems leak through the service ports. the caps help slow the leak down.

 

I'll take a picture to show them. they are one piece...

 

Replace the service ports.
Ford does not use valve cores in their service ports, [most cars].

A/C systems are not supposed to leak, from anyplace.

The only accurate way to recharge an A/C system is with a charge cylinder, [where you can see the amount of refrigerant you are putting into the system, or with an automatic unit, [done by weight].
It is very important that the charge amount is correct, as I said a 4oz overcharge is too much, it will lead to high head pressures and damage to the system. 94

 

Not supposed to but unfortunately they do. From the service ports, hose connections and other breaks in the sytem. This is why cars require periodic recharging of the system. Refrigerant is NOT a gas the evaporates or dissapates in any way, shape, or form with in an automoitve AC system. If the systems were truly airtight the refrigerant would remain fully charged in the system forever. All manufacturers have what they consider acceptable levels of leaks. If you have Alldata or MOD simply refer to the sytem descriptions or operation for further education on the subject. It should also be noted that many state enviromental agencies also have rules on what they consider acceptable levels of leaking.

 

If you mean one or two molecules at a time, then yes, A/C systems leak, hissing, ["until I put the caps back on the line ports after I shut off the car, they were hissing a little"] from service ports is unacceptable, if you think it is, your very wrong, take my word for it, I am pretty sure I know what I am talking about, my shop... http://airwolfeautoair.com/ 94

 

Small threadjack, but still relevant for this thread -- since you did a full A/C reinstall on your Civic, how much PAG46 refrigerant OIL did you add? Assuming all other components were flushed clean of all previous residual oil.

Also, does the full amount of refrigerant OIL go into the compressor on a full retrofit, or do you spread it around to the other components, too? I've received conflicting information on this topic - would be nice to clear it up finally.

 

When we do a retro-fit we add oil, [Ester] to the compressor and the filter/dryer, [filter/dryer must be replaced when doing a retro-fit] although once in the system, [wherever it is added] it will circulate throughout the system suspended in the refrigerant. 94

 

where can I get the replacement service ports and do you have any idea how to replace them? I'm serious when I say I look at them and they look like they are physically a part of the hose assembly itself...

 

Not not one or two molecules more like .25 oz a year. Your little shop is all fine and dandy, but Im an L1/ smog tech and I know what Im talking about as well.