Air Conditioner not engaging

[mrpyb]

So my AC hasn't worked since last summer and I figure I better get it fixed as it is started to warm up over here already. I don't know anything about the AC system, but I do know that when I push the little blue button on my dash my car does nothing. before it stopped working it started dropping the RPMs more than usual and the car would hesitate even at freeway speeds, and now the belt doesn't even engage. I have checked fuses/relays/wiring and everything looks good on that end.
Is this a bad compressor?

[jey]

Probably, and possibly you've lost pressure in the system. The compressor won't engage if there is not sufficient refrigerant in the system, and if your compressor starts to seize then the car will run pretty crappy when it's engaged.

[green97gt]

^yup

you can buy a combo pressure guage for not that pricey, then you will always have it. i find mine really comes in handy.

OR find a shop that wont charge you an arm and a leg to hook guages to it and check your pressure.

then i would shoot some R134A into it and see what happens,

but it your car was running crappy with the AC engaged before, it might be time to swap out compressors.

[mrpyb]

thanks guys.
think I would be okay to just buy some R134A without checking the pressure first?

[nomad666666]

NO!!!!!! you could blow a line, evaporator or condenser you need to check it with a gauge.

[mrpyb]

and where would I buy a gauge? around what kind of price?

[nomad666666]

http://www.harborfreight.com/cpi/ctaf/d ... mber=95808 (http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=95808)
http://www.harborfreight.com/cpi/ctaf/D ... mber=92649 (http://www.harborfreight.com/cpi/ctaf/Displayitem.taf?itemnumber=92649)
http://cgi.ebay.com/ebaymotors/R12-R22- ... 4a9d87bf48 (http://cgi.ebay.com/ebaymotors/R12-R22-R502-R134a-AC-MANIFOLD-GAUGE-SET-BRAND-NEW_W0QQitemZ320470499144QQcmdZViewItemQQptZMotors_Automotive_Tools?hash=item4a9d87bf48)
look around you can find them

[mrpyb]

thank you, i know i've seen the R134A recharge kits at auto parts stores with just a small pressure gauge on the hose. would one of ^these^ be that much better that just a simple (cheap) kit?

[nomad666666]

What I would do with the car OFF grab the center piece of the compressor clutch and see if you can rotate it in either direction if yes then I would get any gauge and check the pressure if it wiil not rotate then the compressor is shot.

[green97gt]

the combo guages are infinatly better that those small (low side )pressure guage.

(seems people on this site have some huge issue with buying tools...you keep them forever)

any time you inject R134A into the system you do so from the low pressure side of the system.

the combo guages will show you both the high/low side of the system, cause even if your compressor clutch kicks on, you compressor might not be working to create the pressure differential needed.

you can probably get by with the little recharge guage if you reaaaaaalllly wanted.

what i would do it let the car sit for a while, then while its not running, or terribly hot, hook up with little recharge guage with an unopened can on the end, or no can(i just dont know how those little ones work) just to read the "static" pressure

static means not running or loaded or whatever, the static pressure should be the same on both high and low sides, if youve let it sit a while cause the high pressure side will eventually equalize with the low pressure side(most of the time)

if you get 0 pressure on a static reading you must have a leak somewhere and pumping more R134a into it probably wont do anything....and the EPA will want your soul. = )

if you get above zero, try shooting some in there and see if your compressor kicks on.

if i remember correclty, my 97 has a 19-23oz system. so keep that in mind when shooting in cans of R134A

[green97gt]

What I would do with the car OFF grab the center piece of the compressor clutch and see if you can rotate it in either direction if yes then I would get any gauge and check the pressure if it wiil not rotate then the compressor is shot.


maybe im misunderstanding, but if he does have any kind of pressure the center of the pulley(that drives the compressor right?) should be very hard to turn, no?

and even if it does turn, it may be worn/damaged inside to the point of not creating the pressure difference.

[nomad666666]

It should still turn with force of like 15-20 foot pounds an educated guess. If turns easy then hard its shot. If no resistance then it might be low or shot. If you can't turn at all then FUBAR! The great thing about this is not being there hands on. Its hard to teach a person how to diagnose a problem with out showing them.

And yes it could be damaged to the point it will not pump. If the engine was laboring more then normal when it still worked then I would think its got bad bearings or the vanes are digging into the case and if he isn't going to do the work himself then I would save the money for the gauges.

[green97gt]

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It should still turn with force of like 15-20 foot pounds an educated guess. If turns easy then hard its shot. If no resistance then it might be low or shot. If you can't turn at all then FUBAR! The great thing about this is not being there hands on. Its hard to teach a person how to diagnose a problem with out showing them.

very true. i really like AC work. graaaaavy.

ive just never heard of testing that way, and i would think that if theres pressure in the system it would be really rough to turn...next time my hood is up im gonna try that tho. :smt026

[nomad666666]

I always liked replacing compressors but I still hate pulling a dash!

[mrpyb]

okay so if i am understanding correctly this is what i need to be trying to turn?
https://sl-i.net/FORUM/images/imported/2010/02/Photo0133-1.jpg

if so, it turns very easily and with little to no resistance. if not, i may need more direction on what i need to be trying to turn :lol:
so buy some gauges, check pressure staticly, if above 0, add R134A to see if it kicks on?

[nomad666666]

take the cover off and turn the outer part the part with the 3 quarter size discs you can use a socket on the bolt but only turn to the right when facing the compressor

If you can turn it then check and charge.

If you can't turn at all then it is locked up replace.

It might turn and still be bad there are a lot of parts inside that can freeze up and break

[mrpyb]

okay it turns with just one finger pressure so looks like i need to check and charge!

[nomad666666]

yep