ac problem

purchased some 134-a refrigerant today because my a/c was getting "cool" and that isn't cutting it,when I threw the gauge on it,it shows it well into the green,then down to low,two seconds later back up,two seconds later back down,so on and so on. I can hear the compressor kicking on and that is when the gauge goes into the green,but like I say that only lasts 2 seconds,what is the deal here?

On a hot day with a full charge at idle the compressor should stay on steady and cycle when the engine is sped up. Sounds like for the most part it is working like it should, but it does sound like the charge is low. What year car is it? Was it a 134a conversion? If it was, the only right way to convert is to change over to the FS-10 compressor, and new style condensor with narrow tubes, and Motocraft YT-12D oil. Also, to really tell whats going on you need a set of pressure gages. The throw away bottles with the green and red dials on them aren't much help. You can get a set of cheapy set of gages from Pepboys for like 40 or 50 dollars. I made a lot of money with a cheap set like that. But, you need to know what your pressures are.

my car is a 93,I took the car to autozone because I was not sure what type of freon it took,when I removed the cap he istantly said 134a,not sure if you can tell from that or not.the compressor is definitly going on and off the funny part is that when the front of the compressor starts to move the pressure goes way down,when the front stops moving it goes back up into the green,of course the compressor is always spinning because the belt is on it but when I see the front of it move the gauge goes to the part of it that says low.

bumpskier45 said:

my car is a 93,I took the car to autozone because I was not sure what type of freon it took,when I removed the cap he istantly said 134a,not sure if you can tell from that or not.the compressor is definitly going on and off the funny part is that when the front of the compressor starts to move the pressure goes way down,when the front stops moving it goes back up into the green,of course the compressor is always spinning because the belt is on it but when I see the front of it move the gauge goes to the part of it that says low.

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OK - what you see is the compressor PULLEY spinning, not the COMPRESSOR itself.

It's normal for the pressure on the suction side to drop when it kicks on. When it drops too low, the cycle switch will shut the compressor off until it builds back up.

I'd suggest a good read on A/C before doing anything else - you seem to be missing some of the basics here (note: no, I'm not calling you stupid, as I've been accused of! Just suggesting knowing HOW it works will answer your current questions.)

Also, since you have a partial charge, it may be worth it to pay a profesisonal to top it off. I'm lazy and paranoid - so far every time I've charged it, I was able to do from bone dry, and was able to weight the R134a in. That's the proper way to do it, BTW ... unless you have a REAL gauge set and know how to read it, complete with the temperature compensation.

RwP

what you just said makes perfect sense to me now,I am going to take it in to a shop today just have them give it the once over,I will bet im just being perinoid and all it needs is some freon and it will be good to go.Thanks again guys always such good information here.

bumpskier45 said:

what you just said makes perfect sense to me now,I am going to take it in to a shop today just have them give it the once over,I will bet im just being perinoid and all it needs is some freon and it will be good to go.Thanks again guys always such good information here.

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Ralph forgot to mention that A/C never needs topping off. You have a leak that needs to be fixed. Otherwise you'll have to add refrigerant again and again. The shop should identify the source of the leak(s). If its Orings on a springlock joint.. those are super easy fixes. If its a hose (which never go bad) its more work. If its the compressor, thats an easy fix. The condenser is not too bad.. the evaporator = major job. Any repair will require evacuating the system, fixing the problem, usually replacing the drier/accumulator, vacuum test, and recharging. Its not usually a cheap job and there are few corners that can be cut.

For example.. using leak sealer. Sure it might get you fixed up for a while, but at the cost of replacing just about everything the next time it needs service.

However... one corner that can be cut: If you have a relatively new drier thats been in a sealed system and you have to open it up again, just vacc it down and reuse the stupid thing. The amount of dessicant in that can is HUGE.. it isn't going to become saturated from seeing open air for 10 seconds. Thats $50 you really only need to spend once.

TbirdSCFan said:

However... one corner that can be cut: If you have a relatively new drier thats been in a sealed system and you have to open it up again, just vacc it down and reuse the stupid thing. The amount of dessicant in that can is HUGE.. it isn't going to become saturated from seeing open air for 10 seconds. Thats $50 you really only need to spend once.

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That MAY depend on where you live.

*checks* Yep, still at 98% RH ... if you think hard about cracking a system open, that dessicant is TOAST!

And if you have the 5.0HO like I do, since the accumulator/compressor hose is part of the accumulator assembly, it's more like $150

RwP (who is replacing his - AGAIN - since he'll be replacing the evaporator while doing the dash and heater core. And since he has/had signs of dye leaking out the drain ... )

RalphP said:

That MAY depend on where you live.
*checks* Yep, still at 98% RH ... if you think hard about cracking a system open, that dessicant is TOAST!

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Presuming that the out of the box drier was sealed until the moment it was installed, its exposure to air is very limited. That and due to the fact that the tubes are small, there is virtually 0 air movement into/out of the can while its initially installed. Nothing moving dry air out of the can nor pushing moist air into the can. If it were to sit open for a long time, hours maybe in humid air, then I could understand the concern.
After installation, normal procedure is to promptly vacuum down the lines which boils off and sucks out the moisture that found its way in. Afterwards, presuming a sealed system which was properly charged, charging hoses burped correctly, then there is no further exposure to moisture from the air because there is no air. A new drier should then be good for the life of the vehicle. When things wear out after 10-15 years of service, IMO, its a good idea to replace it.

When you have new one that you installed, charged up and it blew out 6 months later from a leak that you didn't find.. then IMO your spending $$ needlessly. Shops have different practices because they don't want come-backs.. They'll spend $100s more to pacify Mr. Justin Case and tack it onto your bill if theres even a possiblilty that something related might be worn. That is why they replace high pre$$ure manifold ho$e assemblies... when there's nothing wrong with them. If I followed all their practices the same with my 3 drivers... I'd only have 1 driver instead..

If I were you and I had to replace a $150 part... I'd look into alternatives. If its original or unknown, I'd no doubt replace it. I wouldn't trade it out everytime I had to work on it. Its a judgement call.

Be aware, I drain/strain/reuse tranny fluid and coolant... If I didn't, I'd be broke and my back would hurt from carrying all those things up to the recycle center.

RalphP said:

RwP (who is replacing his - AGAIN - since he'll be replacing the evaporator while doing the dash and heater core. And since he has/had signs of dye leaking out the drain ... )

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Fun job. I've pulled dashes out more times than I can count. Let me know if you want any tips. e.g. chocking the wheels in case you knock it out of gear..

TbirdSCFan said:

Fun job. I've pulled dashes out more times than I can count. Let me know if you want any tips. e.g. chocking the wheels in case you knock it out of gear..

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Oh, the wheels will be chocked. Front end may still be on jack stands, since I'm also doing a partial front clip, reflaring the end of the hard brake line to the passenger front brake, redoing inner fenders, replacing cruise control servo, and redoing the line to the vacuum canister on the passenger side.

I has much planned.

Oh, don't want to forget - new windshield glass!

RwP

TbirdSCFan said:

Fun job. I've pulled dashes out more times than I can count. Let me know if you want any tips. e.g. chocking the wheels in case you knock it out of gear..

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Oh, I chocked the wheels - and didn't KNOCK it out of gear, I had to shift it out of PARK so I could remove portions of the dash.

Which is still not coming out ... I removed the two nuts hidden by the console, the two bolts/screws on the left side, the two on the right, and the four across the top. Are there any others that hold it in place?

*wistful* Wish you were closer - maybe you know the proper profanity to get it to remove so I can swap the dashes and put it back together.

RwP

RalphP said:

Oh, I chocked the wheels - and didn't KNOCK it out of gear, I had to shift it out of PARK so I could remove portions of the dash.

Which is still not coming out ... I removed the two nuts hidden by the console, the two bolts/screws on the left side, the two on the right, and the four across the top. Are there any others that hold it in place?

*wistful* Wish you were closer - maybe you know the proper profanity to get it to remove so I can swap the dashes and put it back together.

RwP

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Oh yeah.. the super secret hidden nut. LH side of the steering column. Behind the ac vent panel. Just below the opening. About 6" back.
Id suggest take the whole steering column out. Theres a 13mm bolt that couples the ujoint to the shaft and 4 13mm nuts that hold the column to the dash.
On the RH side, take the whole glove box out. theres a bolt on the UR inside.

On the center A/C panel, 2 U bent pieces of coat hanger will unlock the clips. There are 2 plastic studs with 10mm nuts holding the vac hoses onto the back. You wrestle with the thing and unplug the connectors, turn it over and pinch the plastic clip that holds the blend cable with needle nose pliers and work it out to get the whole thing out.

Back on the LH side, unbolt the harness. 10mm bolt. Under the hood, you unbolt the harness connector, another 10mm bolt. Grope around and push 3 of the plastic tabs and push the housing into the inside.

Last, the antenna cable feeds through the firewall. You unscrew and pull the fender liner back, unscrew the felt panel fasteners with your fingers. Pull it out and grope wayyyy up and unplug the motor connector and the antenna cable. Once loose, push the firewall grommet up into the pass compartment.

You also have to disconnect everything under the pass side kick panel.
That should be enough to keep you busy for a while.