Air Conditioning Does Not Switch On

1998 Saturn SL2

I was wondering why I was getting no calls from buyers at the auto fair
here. A working A/C is an absolute requirement to sell a car in these
parts.

Anyway, I turned it on, and the compressor was not turning. I had not
checked it, but it had been working 6 months ago in the previous hot
weather, but does not switch on now.

I swapped the A/C and Engine Fan relays----after all, what's the likelihood
of two relays going bad?

Still the compressor does not kick in.

There had been no noise from the compressor when it was working 6 months
ago. Nothing to indicate the clutch going bad.

Does anyone have any ideas before I take it to the shop?

Thanks to the regulars here who make thoughtful responses to this group.

 

....just a guess here - I believe if the Freon level is low, there is a
safety device that prevents the compressor from running. So assuming
there's no leak or failing component(s), the best case scenario would be a
recharge.

 

Thanks for pointing that out. It occurred to me as well that there might
be some other sort of sensor involved.

But I was not aware that the compressor could be damaged if the
refrigerant was absent or even low.

One day, I hope Saturn and other automakers just tell the driver in
flashing signs on the instrument panel: "Bad Relay---Replace" or
"Refrigerant Low or Missing----Re-charge the system!"

 

I'd guess it's low on refrigerant. (it's not freon)

 

....I'm pretty sure the Freon acts as a lubricant - I agree about smartness
in car vehicle sensors. But I guess more folks than not have their vehicles
serviced so adding that would just drive prices up more. Maybe Microsoft
could do a technology transfer with GM and we'd get to Ctrl-Alt-Del when our
car stops running and keyless remote start on our PC's! (grin)

 

fyi - Freon is a trade name for a family of chlorofluorocarbons from R11 to
R227ea. It's usually used as a refrigerant. R12 is the old stuff and R134a
is the newer, nicer stuff most commonly used in vehicle HVAC (and I'd guess
most home/commercial AC...)

 

#1. Refrigerant is not a lubricant. That's why there's oil being circulated
with it.
#2. It's not freon.

--
Steve Barker

=========

 

No, it's not a trade name. It is a long gone BRAND NAME trademarked by
DUPONT.

 

Are the R#'s still valid (like if you went into a parts store and asked for
a can of R134a) ?

 

Yes. 'Cept you won't buy R12. There is a substitute however.

 

Assuming no leak?? If the refrigerant is low, it went somwhere!
Assuming no leak is quite an assumption if the refrigerant is low!

{Delete nospam for email}

 

Well, everyone has an opinion, eh?

 

Well it's not really an opinion in this case. It's fact. If the
refrigerant is low, then there is a leak. PERIOD. It's like a transmission,
low fluid = leak. No other possibility.

 

Okay, then technically is it typical that all AC systems leak? And it's
only when you have to recharge the system more than once a year (or insert
the appropriate period here) is the leak considered a problem? Otherwise
I'm confused. Because for years Sears and Goodyear would offer a AC service
and add Freon as indicated and said it was normal over the course of time
(I'm thinking years, not months) for the level to drop. When I had my
compressor replaced on my 97LS2 because of the whine (suspect bearing), they
said it was low on Freon too and the rest of the system was fine.

 

No, not all systems leak. I've checked systems that haven't been touched in
15 years to find them ok. I myself have a '94 SL1 that has never been added
to or serviced. Some leak, some don't. If it's low, it has a repairable
leak. Period.

Oh, BTW, it's not freon.

 

There are several conditions where the compressor will shut down:

Low refrigerant pressure - not enough volume of refrigerant. When suction
side pressure is too low, the evaporator will ice up solid!

Low ambient temperature - there is usually some temperature sensor that will
cut out the compressor in very cold weather to prevent damage to it. In cold
weather, the refrigerant may not vaporize in the evaporator (cold weather
defrost). Liquid refrigerant flowing back into the compressor dilutes the
oil and can damage the bearings/bore. can also fluid lock the piston.

High pressure cutout. High side of compressor pressure is too high. This one
is unlikely as the compressor would come on for a few seconds and then shut
off.

Best thing to do is to check (have someone check) the low side pressure. I
haven't worked on the new HC134A systems, only the old R12 systems. With the
compressor off, there should be something like 50 psi (iirc).

Oppie
--
----------------
| ...just a guess here - I believe if the Freon level is low, there is a
| safety device that prevents the compressor from running. So assuming
| there's no leak or failing component(s), the best case scenario would be a
| recharge.
|
|
| | >
| > 1998 Saturn SL2
| >
| > I was wondering why I was getting no calls from buyers at the auto fair
| > here. A working A/C is an absolute requirement to sell a car in these
| > parts.
| >
| > Anyway, I turned it on, and the compressor was not turning. I had not
| > checked it, but it had been working 6 months ago in the previous hot
| > weather, but does not switch on now.
| >
| > I swapped the A/C and Engine Fan relays----after all, what's the
| likelihood
| > of two relays going bad?
| >
| > Still the compressor does not kick in.
| >
| > There had been no noise from the compressor when it was working 6 months
| > ago. Nothing to indicate the clutch going bad.
| >
| > Does anyone have any ideas before I take it to the shop?
| >
| > Thanks to the regulars here who make thoughtful responses to this group.
|
|

 

fyi - Freon is a trade name for a family of chlorofluorocarbons from R11 to

My understanding is that the old stuff is freon(R12) while the new stuff is not
freon, but rather R134a. And yes you can get a can of R134a but not R12.

 

So what's in a 97SL2, R134a? (just curious)

I think it would be cool if you could run the AC a half hour before you get
into the car without having to light the motor off - would be great in the
summer, eh? I think I've seen a science mag doing something with solar
panels and peltier (sp?) devices...

 

On my '89 minivan, the suction side hose developed a leak and lost all the
Freon (R12). I replaced the hose along with a new H-valve (temperature
controlled expansion valve) and receiver dryer. Accounted for all
lubricating oil in the parts removed and pumped down. Since I never bothered
to get an EPA license to handle refrigerants, I had a friend refill the
system with FR12 http://www.refimax.com/products/fr12.htm
Generally the same properties as R12 and compatible with the oils used in
those systems (mineral oils). Worked great and at a fraction of the cost of
R12.

Oppie

 

Even most of the r-12 was not freon. Freon is a brand name.