Help with air conditioning

[garfield81]

I have been seeing couple of things related to the air conditioning on my X and wanted your advice before I start working on it.

1.) For the past week the air conditioning takes a couple of minute to start blowing cold air when starting the car first thing in the morning. After that the air conditioning seems to work fine for the remainder of the day. Searching through the forums I found that this is possibly related to the compressor and the compressor might need replacing.

2.) During a long trip over the weekend the air conditioning suddenly stopped blowing cold air (it was cool but not cold) and fan speed on max wouldn't feel as it was blowing as much of air. After a stop over and shutting down and restarting the car everything seems to be normal. Searching for this on the forums it looks like I possibly need to recharge the air conditioner (which someone mentioned would indicate a leak since you never need to recharge). And for the fan speed it sounds like the FSR needs to be replaced.

All in all it looks like I potentially need a new compressor and/or recharge the air conditioner and a new FSR. So the question is should I be replacing them in a certain order like FSR first or recharge the system first to avoid replacing good parts?

[garfield81]

Originally Posted by trader4

I'd start by having the system checked and see if it's low on refrigerant.
That can by DIY, if you know what you're doing.

The AC diminishing together with little air coming out on high could
be the evaporator icing up. Depends if you can hear the blower running
and air is just not coming out, or if the blower isn't running. If it's
the latter, then it could be the FSR..

I'd check the aux electric fan too, though from the problem I don't
see any signs it's from that. But easy to check. When the car is
first started, it's supposed to spin up for 20 secs or so as a test.

Thanks for the reply.
For checking the refrigerant I would just need to connect a gauge to the ac line and check the pressure with the AC running, right?

For the air not blowing, yes, I could hear the blower but no air. Is the evaporator freezing up related to refrigerant being low?

I will check the electric fan tonight.

Thanks again

[garfield81]

Originally Posted by trader4

Paradoxically low refrigerant in an AC system can cause it to freeze
up. I was having problems with mine where once in awhile it
would freeze up, sometimes you'd see just a bit of fog coming out.
It happened rarely, so I didn't pay much attention. Then at some
point it wasn't blowing cold enough air. So, I recharged it. I
immediately had cold air again and the icing never happened again.
The funny thing though is that I fully expected that I'd have to
recharge it again in a year or so, because somehow it leaked out.
But that was several years ago now and it's still working fine.

I just used one of the $20 can with gauge kits available at the
auto parts stores. If you're adding refrigerant, might as well
get the kit that has dye in the can and includes a UV penlight
so you can look for leaks.

And if you can hear the blower running, then it's not an FSR problem.
My best guess at this point is it's low on charge.

Looked at the aux fan and it did start up but only after a minute or two after starting the car.

Also plan on getting a can of refrigerant today. I was browsing online and did not see one with the dye and most of them came with a sealer of some sort which I heard is not good for the system. Is that true?

[David.X5]

most AC folks really oppose the sealer -

a few problems - many garages recover and reuse the refrigerant - the sealer can contaminate their system so some will refuse to touch a car if you tell them or they notice it. Some will even test for it. It can also obstruct the expansion valve and small passages in the condensor / evaporator.

It does work for some people. I imaging those products do get better with time, too.

My neighbor tried it in his 325 and it didn't work, and the dealer insisted he had to replace every component in the AC loop. He traded the vehicle in for $0.50 on the dollar instead. Whether he was conned or not is up to you decide, but that is the risk.

I would only put sealer in a system if I was so broke that it was that or no AC at all, and I wasn't concerned how the loss of the AC would reduce trade-in or resale value... And thankfully I haven't been that broke in a long time ;-)

[garfield81]

Thank you for the replies. I finally had a chance to get the refrigerant and the gauge and had two questions:

1.) I started the car and set the AC to max - opened the hood - and noticed the compressor clutch spinning but the aux fan wouldn't turn on. I left the car running with Max AC for a good 3-4 minutes and the aux fan never spun. Does the aux fan only turn on if the outside temp is hot? (It was 75 degrees outside and car engine was cold as well).

2.) I got the gauge as a separate part and the refrigerant can separate. And the gauge had instructions to check pressure before screwing in the can and only screw in the can if the pressure is low. So I did exactly that and as soon as I clicked in the gauge the needle jumps to 100 psi (As per chart it's supposed to be 35-45). I then unhooked the gauge and needle was stuck at 100. So I pressed the trigger without the can screwed in and noticed a puff of air/gas and the needle reset to 0. I tried it again and the needle again jumped to 100. So do I have a bad gauge?

[David.X5]

The Aux fan does not have to come on immediately, but I have noticed it start up within maybe a minute under conditions like that. Do you have software you can use to test the fan?

You need to describe more about the test you did with this gauge. Is this one gauge or a set of two gauges with a manifold like AC technicians use? If it was a two gauge set, did you open or close the valves on the manifold?

Did you get that pressure reading with the compressor running or not running?

What was the outside temperature?

The part of your comment where the gauge is holding pressure until you release it does not bother me - it probably has a check valve.

[upallnight]

Originally Posted by garfield81

Thank you for the replies. I finally had a chance to get the refrigerant and the gauge and had two questions:

1.) I started the car and set the AC to max - opened the hood - and noticed the compressor clutch spinning but the aux fan wouldn't turn on. I left the car running with Max AC for a good 3-4 minutes and the aux fan never spun. Does the aux fan only turn on if the outside temp is hot? (It was 75 degrees outside and car engine was cold as well).

2.) I got the gauge as a separate part and the refrigerant can separate. And the gauge had instructions to check pressure before screwing in the can and only screw in the can if the pressure is low. So I did exactly that and as soon as I clicked in the gauge the needle jumps to 100 psi (As per chart it's supposed to be 35-45). I then unhooked the gauge and needle was stuck at 100. So I pressed the trigger without the can screwed in and noticed a puff of air/gas and the needle reset to 0. I tried it again and the needle again jumped to 100. So do I have a bad gauge?

You could have a bad gauge set, or you might not know how to use the gauge properly. Where did you buy the gauge set? Is it a gauge set that measure the low and high side or just the low side?

[garfield81]

Originally Posted by David.X5

The Aux fan does not have to come on immediately, but I have noticed it start up within maybe a minute under conditions like that. Do you have software you can use to test the fan?

You need to describe more about the test you did with this gauge. Is this one gauge or a set of two gauges with a manifold like AC technicians use? If it was a two gauge set, did you open or close the valves on the manifold?

Did you get that pressure reading with the compressor running or not running?

What was the outside temperature?

The part of your comment where the gauge is holding pressure until you release it does not bother me - it probably has a check valve.

Thanks for the reply. Answers below:

-This is just a single gauge for the low side.

-The compressor seemed to be running. (AC was set to Max and the clutch seemed to be engaged)

-outside temp was 75

Also have to add with the Max Ac turned on all it was getting was warm air through the vents. Maybe I should drive the car around for a bit to get it blow cold air before doing a pressure test.

[David.X5]

It's just a guess, but I suspect your compressor didn't turn on and you are measuring the static pressure in the system. This makes more sense if the engine/compressor was warm (say around 90 F). You have to find a way to force it on or troubleshoot that problem first.

[garfield81]

Originally Posted by David.X5

It's just a guess, but I suspect your compressor didn't turn on and you are measuring the static pressure in the system. This makes more sense if the engine/compressor was more (say around 90 F). You have to find a way to force it on or troubleshoot that problem first.

I remember reading on the booklet that came with the gauge that if the compressor does not turn on then fill half a can of refrigerant. Something about that did not feel right so I didn't do it. Maybe I'll first try driving the car around a bit till the ac starts blowing cold air and then verify pressure.