Checking refrigerant level - '02 Accord

Does anybody know if the Accords from '98 - '02 have a "sight glass"
anywhere in the A/C lines to visually check the R-134a level without
gauges? My previous Accord, a '92, had one on the receiver-drier but
that was an R-12 system. I found what looks to be the receiver-drier on
my '02 (small cylinder in front of the radiator, has A/C lines going in
and out as well as an electrical connection, probably to shut off the
compressor if the R-134a pressure is too high or low, but no sight glass
found anywhere).

Also, are the "stop-leak" compounds offered in some varieties of R-134a
really effective at all? In this case I suspect a pinhole leak
somewhere since the performance of the A/C has deteriorated gradually
over the last 3 months or so (43K miles at present, no visible damage to
any of the lines). If so I'm tempted to do a DIY charging job with the
gauge set rather than pay $75 or more just for the diagnostic.

Any advice appreciated -

Mike

(remove "antispam" for direct replies)

 

I'm afraid the sight glass and recharging by guage went out with R12. The
experts say R134a has to be charged by evacuating and putting the correct
weight of refrigerant in.

If you weren't using the defroster often in the winter the seals may have
lost their oil and leaked some refrigerant out, but whether the charge is
correct now and whether the system is leaking now only a pro with the actual
service machine can tell you. (Well, once the system is emptied you can do
your own evacuation and leak test if you have a refrigeration pump, and I
suppose you can get a larger than correct canister and use a scale to tell
you when you had transferred the specified charge.) I did all my own A/C
work in the days of R12, but now I just don't have the equipment to do a
competent job. Any auto parts store will sell you stuff to do an incompetent
job.

In an '02 you don't want to start doing the stop-leak bandaid. Wait until
the car is at least 10 years old before dropping to that level of service.

Finally, verify the temperature control cable adjustments. If the mix door
is still adding heated air or if the control valve isn't closing off the air
will never get cold.

Mike

 

Michael Pardee says...

Could you explain the need to evacuate? Why couldn't you
just add refrigerant until you have the right pressures,
thereby replacing what has leaked out over the years?

 

Not an expert, just parroting what the guys who claim to be:
R134a can't be filled by pressures. (Actually, R12 could only marginally be
done by pressures - my former boss was a refrigeration man in a prior life
and he could do it by filling until he felt liquid in the compressor return
line and then venting until it stopped. I tried to feel what he was
describing gut I couldn't tell. He could estimate the pressures based on the
outside temperature and humidity but never relied on them.) Apparently the
pressures with R134a are only a measure of condensor and evaporator
temperatures and don't relate in any useful way to the amount of
refrigerant, like pressure in a propane tank only tells the temperature and
not the amount of propane inside.

I've tried to fill R134a by pressure and only succeeded in messing things
up, so there must be something to it.

Mike

 

-----------------------

Have you changed your cabin filter(s yet? If they're plugged, you'll
only move about 1/2 as much air thru the system as you should, whether
on RECIRC or regular.

'Curly'

 

Yup, that actually _is_ something I did on my own since I didn't want to
pay the dealer $109 for the labor disassembling virtually everything on
the front-passenger side under the glove compartment.

Airflow has never been a problem. However, ever since the car was new
the air coming out of the vents (with A/C and RECIRC both off and with
the temperature dial all the way to Cold) always was slightly warmer
than the outside air. I assumed it was unavoidable that any incoming
air would pick up some heat from the heater core - my '92 was the same
way. In any case, the difference in A/C performance when I'm at freeway
speeds versus sitting idle at stoplights is much more obvious lately.
That difference was only slight in previous years.

 

Mostly, that sounds like the compressor is going bad. The valve plates leak
and otherwise don't perform well, and that effect is minimized when the the
engine is turning faster. An '02 sounds awfully new for that, though -
usually it takes about 10 years to reach that point.

Another possibility is that the condensor fan has quit. The airflow on the
road takes over to make the fan unimportant while cruising. The fan is
something you can check yourself, while the bad compressor is a conclusion
even the experts reach when everything else checks out okay.

If the refrigerant is low, the cooling is the same at idle as at speed, but
the compressor cycles more often at speed than at idle.

Mike

 

If the dial is all the way cold then no coolant should be flowing through
the heater core. This was a common problem on the 92 and was a result of the
cable adjustment on the heater core coolant valve.

 

More details: if the compressor is in fact going bad, is it possible
that visible "vapor" coming out of the inside vents is a symptom of that
failure? It rarely happens, but at 26K miles I reported this to the
dealer during a routine maintenance visit (it was documented but they
couldn't find a problem at the time). So there is a chance I could get
this fixed under warranty since I reported it early on, even though the
warranty has since expired. Compressor fan is OK.

 

Lemme correct that last sentence - condensor fan is OK. Tells you how
much I know about A/C....