A/C Issues.......need insight

Gro Harlem · Post by **Gro Harlem** » May 2nd, 2005, 6:49 am

I installed my LSD and stuff this past winter & also removed the engine & sprayed the engine bay green.

When I did that, I unbolted a lot of the a/c lines and moved them out the way (not forcefuly, they bend pretty easy). I also unplugged a bunch of wires and stuff. I thought I put everything back the way it should be.

But a couple months ago, when I went to turn the a/c on, the A/C light lit up on the button, the compressor clicked on (the idle went up & the fans turned on) but no cold air....I'm basically 1000% ignorant when it comes to a/c systems. I don't understand how this s--- works at all.

1) Where are the relays located? What other wiring connectinos should I check?

2) Any way to test the valves or anything on the system? Is there any way to tell if i have freon in the system or check for pressure? (and lets assume it is a compressor/wiring issue).

3) And if my fears are realized and I somehow ruptured a line & leaked all the freon out....is there any proper way to repair the line so I can refill the system?

4) And worse yet....if its my compressor...is there any way to replace it without having to recharge the system? (probably not lol...)

BTW: I have 10+ cans of R12, I'm not downgrading to that shitty R134 crap. My dad stockpiled a bunch of cans back in 1993 when the announcement was made about the ban of R12. He bought each can for like $1.89 back then he said.

Oh yah, for the record, MY AC WORKED PERFECTLY FINE PRIOR TO ME WORKING ON THE ENGINE BAY THIS WINTER!! It blew colder than my damn protege's a/c which is impressive in itself. Almost as cold as my mom's 93 camry (which is also r12..and insanely cold).

psneddon · Post by **psneddon** » May 2nd, 2005, 7:13 am

If the fans turn on and the compressor clicks on then the electrical side should be ok. It does sound like you might have created a leak in one of the pipes.

1) In my UK MX-3 the relays are the big rubber coated boxes (3 or 4 of them) at the top left of the engine bay, they are pretty obvious.

2) You can push a key or something into the low pressure side (larger tubing) and see if there is pressure, although you wont know how much pressure.

3) I think you would really need to replace any broken pipes as a repair would not last very long I dont think.

4) No idea.

If you have that may cans you could try putting some of it in, with a 1/4 of a can you would see a temp drop enough to validate if it is low freon.

Other then that I dont know how any faults with the A/C parts within the dash would show up? Is the evaporator part electrical?

Paul

Grants · Post by **Grants** » May 2nd, 2005, 7:21 am

If thers no gas the compressor won't pull in as the controls run through a pressure switch. You sure the compressor clicked? Can you watch it and make sure the clutch is actually pulling in? Just look at the front of the compressor - it should be stationary with the a/c off. Get someone to turn on the a/c and the clutch will pull in, engage the compressor, and the front plate chould be rotating. This is the first thing you need to determine. If it doesn't, stick a volt meter on the clutch wire and see if you got 12V with it on. If you haven't got 12V, run a jumper to the clutch and see if it pulls in and gets cold then.

If thats working, you should be getting cold air. If its working and no cold air, it means you might be short of gas AND your pressure switch has failed. Or you got a blockage (unlikely unless the systems been open to the atmosphere). See, once the compressor is turning its just a pure refrigeration cycle:
- compress the gas
- high pressure gas to the condensor where it "condenses" into high pressure liquid refrigerant
- through the TX valve at the evaporator where it rapidly expands so gets cold (you know like with a nearly frozen bottle of coke when you open it and release the pressure it starts to freeze? Same thing)
- low pressure through the evap, back to the compressor where the cycle starts again.

First thing I'd check is that the compressor is engaging. If so then check theres pressure in the system by opening one of the valves quickly.

Your questions though:
1. The relays are by the firewall. Theres about 4 of them I think but I wouldn't think they are the problem because the fan is working, etc
2. Find the access valves theres one on each pipe and usually has a cap on them. They're like a tyre valve so just check for pressure very quickly with a match or something.
3. I'd worry about that later only if there is a leak, but don't forget there is a lot of pressure in there so its gotta be repaired properly.
4. You're right unfortunately - no.

Gro Harlem · Post by **Gro Harlem** » May 2nd, 2005, 8:42 pm

Ok about the tire valve. I know one is up in the passenger side up near the firewall.

What is a "match" and how would i check the pressure? Would I just unscrew the valve really quick and listen for stuff to come out? and then quickly close it?

And yeah, I figured the relays were those 4 black rubber covered thingys in the corner. They are plugged in. Dunno if they work but they probably do.

I'll have to try the thing with the a/c compressor. I know exactly what you are talking about...teh pulley spins & the center thing w/those weird 3 circular thingys attached spins by itself as well. I KNOW the clutch is fine in the compressor though, but maybe the switch is acting up.

Also, another thing.

Wtf is that metal thing attached to the bottom of the compressor. Its towards the oil filter & has a hex-shape on it (i'm guessing so you can unscrew it). It looks like a valve. Someone on clubprotege told me that could cause problems too. What exactly is it?

Grants · Post by **Grants** » May 2nd, 2005, 10:00 pm

What is a "match" and how would i check the pressure?

Just a match to light a fire - or use a small screwdriver. Theres a valve under the cap like a tyre valve so just push it in.

Check theres gas in it first and then try the thing with the compressor.

Don't know what the thing on the bottom is your referring to, can't even think what it might be. I'll try and have a look later and see if I can work it out.

Yoda · Post by **Yoda** » May 2nd, 2005, 10:03 pm

I you feel that the eletromagnetic clutch is engaging and compressor is working fine, then look at the sight glass on the firewall with the car that the A/C running.

If you see bubble then you have had a leak and loss of refrigerant. If it is foamy when the system is operate but goes clear immediately when the A/C is switched of then the system is operating normally. This is assuming that there is still referigerant in the system