Help - Air Conditioning Problems and DIY solutions for Dummies

[AlabamaDan]

Ok. I've read lots of threads on here about people asking questions about their air conditioner not working as it should. Most of the responses around here start with asking what the hi and lo readings are, etc. Most of those threads just die out.

Many of us don't have those fancy gauges to read all the pressure levels. Yes I could go out to Harbor Freight and buy a set for $50, but then I don't know how to read them anyway.

Now at AutoZone or O'Rielly's they have cans of r134a, with stop leak and oil conditioner. One of the cans even has a connection hose and gauge. This gauge is right up my ally with colors like green is good, red is bad. (I realize I might get some flames from some and "Member Standards May Vary" replies.) But, will buying some of this stuff with that simple gauge work?

Thanks for looking and any help.

[elwesso]

I wouldnt buy a can of stuff until you figure out that you need a can of stuff.. I have this little pencil gauge thats nice for quick readings.. It looks like one of those tire pressure gauges except its for refrigerant. its not accurate like my manifold gauges are, but its a decent alternative for something quick to give you an idea where you stand.

Honestly, what I would do is see if you can get a shop to hook the gauges up. Most AC shops give free diagnosis (since all they do is hook up the gauges) and you can try and see if they'll give you the readings. Should be at 1500 RPM, drivers window open, recirc on, 65F on display, fan on max.

What is the AC doing? Just not cooling as it should? Please give an accurate description of your symptoms.

[AlabamaDan]

OK. I was thinking about it and figured that since I've started working on my car I've spent 1000s on air compressors, air tools, tool sets, good floor jacks, parts, etc. Why be a cheapo now and now spend $90 on guages? So, I went to Autozone, O'Rielly's, and eventually Harbor Frieght. Their $70 manifold gauge set was on sale for $40, so now I'm the owner of a manifold gauge set. AND after conversations with the guys at the parts stores...those guages are nearly as scary. So...

What's the problem? Just blows hot air.

I've checked and the clutch on the compressor comes on when I turn to AUTO and 65 degrees. Just blows hot air.

I'm reading the FSM now. Should I do this self diagnosis stuff? Just it just run through its tests, provide a number and then go back to normal?

I'll have high and low numbers this afternoon.

Also, I bought these three cans. Looks like interdynamic makes the majority of all this auto ac stuff:

13oz ArcticFreeze Ultra Synthetic refigerant 143a+ with advanced leak seaker, mosture and acid eliminator. (Sounds great doesn't it!)

13 oz. Can of High Mileage Refrigerant R134a with Leak Sealer Full Refrigerant Charge with Anti Wear and Lubricant Restoring Additives for the Frequently Used or Older AC System.

R-134a High Mileage 2 oz. Oil Charge

[maxnix]

There is a reason one needs a license to work on refrigerant systems legally. That's all I'll say because this has all been discussed before.

[elwesso]

I dont think you need a license to deal with R134, just R12, unless of course we're talking about operating an AC shop.

Get your readings Dan, call me if you have any trouble when your trying it (my number is on Q45.org) and we'll get you straightened out.

It could be that your low, but we wont know for sure. Do you hear any refrigerant moving? When was the last time you had the system working?

[AlabamaDan]

VERY basic videos: http://www.id-usa.com/how_to_videos.asp More basic that what I was looking for, but I post for others.

License? We don't need no stinking license!

It hasn't worked perfect in years, but I just can't take it any more. I might give you a call later tonight Wes. Probably around 6:30 or 7:00 if that's ok.

Here are some more good videos: http://www.expertvillage.com/v...r.htm
Modified by AlabamaDan at 3:10 PM 6/19/2008

[AlabamaDan]

OK. Let me make sure I'm understanding the table on HA-31.

With the system working properly and the inside air temp is 86 degrees F, then the air coming out of the center vents should be 56-59 degrees F.

AND, with the system working properly with an ambient (outside) air temp of 86 degrees F, the low pressure side should be 28.0 to 31.6 PSI. The high side pressure should read 192-232 psi.

Right?

I notice on the trouble shooting charts on the next pages, none of the causes are 'low refrigerant."

[qsiguy]

Working on the A/C isn't rocket science, you'll be fine. Just get the hoses attached and get high/low readings and report. If it's low on freon both high and low will be low. I've fixed the A/C on several cars and they have all worked out fine. Had a couple with a slow leak, just fill it a couple times through the summer and it's all good.

Couple reminders. When you have the high and low hoses connected do NOT open both valves. You'll pressurize the low pressure side and that will be bad. Also, after you disconnect the hoses from the car they may still be pressurized, check the gauges. If they are be careful taking the hoses off the gauges, where some gloves or wrap a towel around it while the pressure releases.

[AlabamaDan]

It's all fixed. Read about 30 on the low side and and 215 on the high side. I think putting the drive belt helped the most.

[elwesso]

LOL! Glad it was easy..

[AlabamaDan]

In an effort to make this a helpful thread for others...you'll need additional stuff:

The kit from Harbor Freight doesn't have a can tap. I got this Mastercool 85510 R134a Can Tap Valve-Screw-On Model from Napa Auto Parts for about $12.



You'll also need a thermometer to read the temp in the car and coming out of the vents. I used the ac controls to get the ambient temperature outside the car. I had one of these in the kitchen.

[AlabamaDan]

I couldn't find such a thing anywhere else so here it is. For a DIY step by step, here’s how I checked my AC. I do ask that more knowledgeable NICO gurus read what I did and correct me where needed. This will help me learn and also provide a guide for future NICO members.

Please note this is just a step by step analysis of what I did. I am not a certified mechanic and these are not perfect steps for you. Anything you do regarding this system has a risk and if you are not comfortable doing anything here, please see a real mechanic. You have been warned and I am not responsible. Don’t get this stuff on you. Don’t release stuff into the air if you can help it. Don’t put refrigerant into the high pressure side.

Do not mix R134a stuff with R12 stuff. From what I’ve read don’t even use equipment for R134a that has been around R12. The stuff mixes and turns to a jelly or something. Bad! Bad! Don’t do it.

Step 1: Assemble the manifold gauge kit. Looking at the gauge cluster, the blue side on the left is the low side. Attach the blue hose with the angled connector to the bottom of the gauge set. Connect the blue quick connector to the other end of this hose.

The right (red) side is the high side; repeat the connections for that side, using the red hose and the red connector.

The tips on the left and ride sides of the gauge set are for you to connect the quick connector to until you’re ready.

The yellow hose is the hose that will be used to connect to the can of r143a, or whatever you have. Connect the angled end of the hose to the bottom of the center T connector on the gauge set. Connect the Can Tap Valve to the other end of the yellow hose.

Now, make sure all the connections are tight, including where the valves and connectors physically go into the gauge set. Mine were loose.

Step 2: Connect the manifold gauges to the car. Turn the car off. Close all valves on gauge set. Hang the gauges by the hook from the hood latch.

Using the quick connection connect the blue hose to the low side of your system. VERY IMPORTANT. The low side is back toward the firewall. The nipple is marked with a “L” on the green cap. Check fittings for leaks and again make sure the valves are closed by turning the knobs counterclockwise.

Using the quick connection connect the red hose to the high side of your system. VERY IMPORTANT. The high side is toward the front of the engine bay beside the batter. The nipple is marked with a “H” on the green cap. Check fittings for leaks and again make sure the valves are closed by turning the knobs counterclockwise.

Step 3: Prepare:

Refer to page HA-31 of the FSM for more on information checking the pressures. The hood will be up, (duh?), close all doors, all windows up, except driver’s window.

Make sure all the hoses and such are not in the way of the belts, fans, etc. Let idle with the AC on for about 5 mins. Set the ac to auto, 65 degrees, recirculation and coming out of the vents. This is max cooling.

Make note of the ambient (outside) temperature. Helps to be in the shade. It was about 80 for me. Make a note of the temperature inside the car; it was also 80 for me. Take your temperature gauge and stick it inside the center vent, make a note of the temperature coming out, mine was about 100. While you’re waiting for the car to warm up look under the car on the passenger side and see if the magnetic clutch on the compressor is engaging. (This is when I noticed my belt wasn’t on. Should’ve looked here first. . After it was on the temp of the air coming out of the vents was 70. Hey, at least I’m honest to say what it was. Might be someone else’s problem someday. Since it was only 10 degrees cooler I proceeded.)

According to the chart on HA-31, if the temp in my car is 77 (closest to 80) and the humidity is 60-70, which is roughly, is I didn’t measure, the temp of the air coming out of the vents should be 52-56 degrees. I was at 70 degrees.

Then get a helper to sit in the car and bring the RPMs to 1500.

Step 4: Check the Pressure.

Get a helper to sit in the car and bring the RPMs to 1500. Open the valves one at a time to measure the pressure. Turn the blue dial counter clockwise to open it, make a note of the low pressure reading in PSI. Turn the blue dial clockwise to close it.

Turn the red dial counter clockwise to open it, make a note of the high pressure reading in PSI. Turn the red dial clockwise to close it.

DO NOT OPEN BOTH VALVES AT THE SAME TIME – EVER.

According to the chart on HA-31, if the temp outside is 77 (closest to 80), the low pressure should be 27.6 – 31.0 psi. The high pressure should be 178-208.

The ongoing pages of the FSM talk about what to do if things are high and low, but honestly I went with this. If it’s high let refrigerant out, if it’s low add more. Mine was low on both hi and low pressures.

Step 5: Add Refrigerant. Choosing the right refrigerant is just a matter of what you think you need, as long as it’s R134a. If you have to add one you probably have a leak – how else would it get out unless you’ve been playing with those connections. I chose one that had a little oil since it hadn’t been maintenance in who knows how long. My can also had some stop leak in it. Hopefully the leak is small and this can fix it.

Make sure all valves are closed, by turning them clockwise. Shake the can like you would paint for a minute.

Open the valve on the can tap all the way to retract the puncturing device. Screw your can of r134a onto the tap until it stops. Close the valve by turning it all the way clockwise. This will now puncture the top of the can and when you open allow refrigerant to pass into the yellow hose. Open the valve back up.

To allow the refrigerant to pass from the yellow hose to the system, via the low pressure side, open the blue valve. You can watch the stuff through the little glass window (sight glass) above the yellow hose.

Continue to shake the can as stuff flows in. The can will get cold. Really cold.

Keep an eye on the low pressure gauge to determine how much you have in there. Remember, you’re shooting for 27.6 – 31.0 psi. I took that to mean 31.0 psi.

You don’t have to move all the way up to 31 to begin with. Let in some, close the blue valve. You can always let more in later.

Have your buddy in the car keep an eye on the thermometer in the dash. It should drop the temp as more refrigerant goes in and the low pressure goes up.

As my pressure approached 30psi, the temp of the air coming out of the vents was 45 degrees! It’s about 80 in the car and the air coming out of the vents is 45! What an improvement.

Step 6: Finishing. After you’re satisfied with your low pressure and the cooling of the air coming from the vents. Close all the valves – The blue one and the one on the can should be the only ones open. You can open the blue one again and leave it for a minute to get a stabilized pressure reading. Close it good and you can do the same thing for the red one. Again, don’t open them both at the same time.

When you’re happy with everything, keep all the valves closed and disconnect the blue and red quick connections from the system. Connect them back to the sides of your gauge set. Replace the green caps on the car – in the right place.

You can now disassemble the set and put it back into the nice neat little case. The lines will still have pressure on them as will the gauge set. Don’t get this stuff on you, use gloves or a towel. If the can is still partially full, keep the can tap connected to it with the valve fully closed for future use. (I just went over to the QX4 and did stuff on it, using the rest of the can.)SO…….how’d I do? What’d I do wrong? What did I forget?

[DrewQ45]

I couldn't find such a thing anywhere else so here it is. For a DIY step by step, here’s how I checked my AC. I do ask that more knowledgeable NICO gurus read what I did and correct me where needed. This will help me learn and also provide a guide for future NICO members.

Here is my AC conversion thread from a while back with link to a video. I think you found pretty much the same info I did.

zerothread?id=235199

http://www.id-usa.com/video/re...h.wmv

[maxnix]

Here is a post from the Yahoo board that is very comprehensive.

Yes, you do need a license to work with R22 and R134a. Yahoos don't have the machine to captures teh refrigerants so they go into the atmosphere and do no good and are persistent.

A/C systems work through a compression and decompression of gasses/liquids. Much like a can of compressed air gets cold when you release the pressure, liquids inside your A/C system, the portion inside your passenger compartment inside the dashboard gets cold when the compressor-created liquids go through a small valve and expand into a gas. The gas is returned to the compressor and re-compressed into a liquid.

When you run low on this liquid (a refrigerant), one of the symptoms is thatyour compressor will not work, to avoid damaging it. This is done with alow-side pressure switch. In other words, you MUST have X pounds of pressure seen before the compressor will kick on and allow your A/C to work. There is a high side pressure switch for safety purposes to ensure that the compressor doesn't run continuously and blow out the tubes. blockages of compressor parts inside (worn down or broken) can block the expansion orifice where the conversion of liquid to gas occurs (right at your firewall in the engine compartment) which give that cooling effect.

Leaks often come from old/worn seals, corrosion that comes from acidiccontamination (mixture of refrigerants and non-refrigerants, like sometimesair), old/worn compressors, or damaged compressors.

While you can buy a can of refrigerant (R134 in your case), and put it in toyour system via a special hose/connection, it may just escape as well, due to any of the above causes. Sometimes very slow leaks in seals take a long time to leak out, so that may work for you...for awhile.

Air conditioning systems have 2 external connections, a high and low side port. They are different sizes, for safety reasons. A high side port can show several hundred pounds of pressure, which would destroy any can you attach. This high side is seen AFTER the compressor. The other port (low side) is also called a "suction port", because it has a gasseous side that is fed or sucked into the compressor. This is the port that you fill your A/C side on.

You typically attach the hose from the can of refrigerant and then connect to the low side suction port. The refrigerant will flow into the system, andhopefully, the pressure will get high enough to trigger the low pressure safety switch to let the compressor run. But it wont' run as efficiently as it could, due to air in the line that is being compressed.

A proper A/C job would be to diagnose why you have leakage (and it may be a very slow leak, but then it could also be a worn seal or worse).

After fixing it, certain parts are replaced if your system was opened up, assome parts have very small passages that are extremely hard to clean out and it's easier to ensure that it's replaced than to worry you didn't get something out of it. There is also a "drier" in the system that absorbs water and pulls it away from the air conditioning refrigerant. When you get a hole in the system or open it up for service, the water in the air starts being drawn into the drier and uses up the dessicant there. So it's often replaced as well.

Then a pressure test is done with an inert gas to avoid leaving any residue that could mix with refrigerant or eat at the A/C system and lines later.

Then all gasses are vacuumed out with a 2 stage vacuum pump for a long time, to allow any liquid water stashed deep in your lines to boil away - just like you might see a soda releasing bubbles when you turn the cap. But this vacuum takesawhile, and also is used to see if you have any holes in your system.

Then, with a very deep vacuum pulled on your system, new refrigerant (andspecial oils if your system had parts replaced) are added. It will take somepart of the refrigerant on its own, due to the vacuum, but it will require thatthe low pressure switch get activated, and then the compressor kick on, and suck the remaining amount needed.

Filling it too much or too little can lead to poor performance or even failureor non-operation of your A/C system.

Too much to learn, I know. But trying to explain what's going on inside, andhow a can added to the system may help temporarily, but why it might be good to get a service call made. These repairs can be expensive...

My 99 Infiniti had a clutch seize up, destroying the seals on the compressor. I replaced the compressor, seals, drier, hvalve, vacuumed and refilled the system, and it's going great over a year later. I'm also a licensed A/C tech (well, it took 20 minutes online with an exam, but I understand the physics behind what's going on.) I'm also obligated to follow EPA rules regarding the storage of reclaimed refrigerants. My tools aren't cheap. That's why people turn to those little cans on the shelf at walmart to refill their systems. But the EPA is eying the ability for consumers to even buy refrigerants, due to damage to theenvironment. Rather than incur severe wrath of consumers no longer able to cheaply keep A/C going, they try to find safer refrigerants to use that also work well. That's why we all went from R12 refrigerants to R134. It's not as effective, but it's much safer for the environment.

I know, all this is more than you wanted, but shoudl give you a greaterappreciation and knowledge for how the A/C system works.

There will be a test on Monday. :-)

Justin

[AlabamaDan]

Agreed. That is the 100% correct method to fix an AC system. BUT, sometimes we have to turn to a DIY solution - especially in this economy.

[fixer]

you forgot the most important first step. If you were a licensed technician you would know that the refrigerant is under pressure and can cause severe damage to the eyes on contact. dont forget the safety glasses!!!

[Q45tech]

Over oiling from using cans to fix a slow leak can be almost as bad as under oiling.

The correct amount of oil must be within +- an ounce [12%].

[peterr22]

So since we are on the subject maybe you guys can help..

When I got my car the ac didnt work. So i added like 3 cans of storebrand r-134aand got it working sorta..

what it does...works fine in the morning, but after about 20 mins on the roads the compressor starts cycling on and off real fast with no constant sequence to it

So i brought it to a shop and had them do it right (recover, remove oil, vaccum, and charge) and it worked for a few minutes then started doing the same thing. they said when they removed the oil that there was way too much in there.

So it works in the morning but then starts cycling shortly after. and doesn't work often in the heat unless I am actively accelerating..

Any thoughts??

Im thinking a high pressure switch but it also would make some sense with the low pressure witch (accelerating).

I know a little bit about a/c systems but could use any help because the shop told me the compressor was making noise so it might need to be replaced.. but i dont think a compressor would cycle like that without some kind of switch telling it to do so

[qship96]

Sounds like the pressure is too high, measure it with a gauge. Check all fans for proper operation{underhood} make sure radiator/condenser fins are clean and unblocked.

[peterr22]

everything is clean and works like it should (fans/etc) do you know what the high pressure switch is set to cut out at?

[qship96]

You would need to look in the service manual for your model/year of car,the manuals are available for download somewhere on this site.

[maxnix]

http://www.nicoclub.com/FSM/Q45/

[peterr22]

I figured out the problem...It was the high pressure switch connector, there was a bunch of corrosion on there so it wasnt making a good connection. I cleaned it off and it works fine now. Thanks !!!

[SnowSurfLax]

What's the easy way to oil the system? My compressor just started rattling and I don't want to have to replace it. Sorry if I missed it, but I'm at work and websense sucks hairy beanbags and hampers my ability to read long sets of info.

[qship96]

What's the easy way to oil the system? My compressor just started rattling and I don't want to have to replace it. Sorry if I missed it, but I'm at work and websense sucks hairy beanbags and hampers my ability to read long sets of info.

Impossible to determine how much oil is currently in system without complete disassembly/flush components/reoil to spec

Just adding oil to current system is not the answer, and probobly not even the problem

[SnowSurfLax]

Yeah, that's what I was afraid of. Oh boy!

[AlabamaDan]

I can't believe I couldn't find this before. This is a totally great set of articles.

I found this for you:

A/C Compressor Removal/Replacement

And this for some background:

The End-All Air Conditioning Article

[SnowSurfLax]

That's some great info! Thanks!

Funny thing though, I think the rattle went away. Even after waiting at the border for an hour or so. Very odd. I'll check it when I head out later today to run some errands.