1991 A/C Recharge Question

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Bill G - 23 Jun 2004 16:59 GMT

Hey,

My A/C compressor has been moaning and groaning for about 5 years now. It
works very well in the cooling department, but it just makes noise. A
mechanic neighbor of mine told me not to worry about it and just replace it
when it finally fails. During those 5 years, I've lived in relatively
cooler climates (Portland, OR and Traverse City, MI) so I haven't needed it
very often (5-10 days a year). But, I might be moving to Chicago soon, and
it might be parked outside, so I'll need it more in both the summer and
winter.

There's a junkyard in town that has a '90 compressor from a wreck for $65.
If it doesn't work, I can return it.

Questions:

How do I discharge/recharge the cooling system? I'm not keen on just
letting the stuff float away (I'm one of those so-called "environmental
whackos").

Can I do it myself (the recharging)? If so, what do I use? Are there
different grades of coolant?

How much is a rebuilt compressor going to cost me and is it worth the extra
money over the wrecked one?

Are there any other related repairs I should look at doing at the same time?

Thanks,

Bill G
'91 SE Auto
166k miles

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JimV - 23 Jun 2004 19:10 GMT

> Hey,
>
[quoted text clipped - 29 lines]
> '91 SE Auto
> 166k miles

You can't do it yourself. It needs to be evacuated and recharged
properly (with special equipment). For what it's going to cost you, it
doesn't make sense to install an unknown compressor. Get a Nissan
rebuilt. I advise you to choose carefully who you have do this work.
It's not something your average garage that doesn't specialize in AC
work is likely to do right.

Reply to this Message

Steve T - 24 Jun 2004 01:07 GMT

> Hey,
>
[quoted text clipped - 3 lines]
> it
> when it finally fails.

He's right. I've seen them go 10+ years making "buzz-saw" noises. The only
advantage with doing it now is: if this one does "explode" internally they
can spit trash into the condensor which will then have to be flushed out.
Ussually they just lock up and don't cause any other problems.

This isn't something you can do yourself as far as recovering the freon and
given it's probably an R12 car, I don't recomend "converting" it to 134a as
they never cool as good unless they were designed to use that stuff. I'd
leave well enough alone.

Signature

Steve

http://www.atlantaracing.com

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BuddyWh - 24 Jun 2004 01:28 GMT

>Hey,
>
[quoted text clipped - 9 lines]
>There's a junkyard in town that has a '90 compressor from a wreck for $65.
>If it doesn't work, I can return it.

Be careful.... if it has been removed from the system, he should have
sealed the fittings with cap plugs to keep insects and such from
contaminating the inside. Even if sealed, the interior could start
to corrode if it has been "open" for a long time since the surfaces
are no longer protected by the compressor oil. The warranty is all
well and good but corrosion may not cause immediate failure, and it
could damage other components in the system.

>Questions:
>
[quoted text clipped - 4 lines]
>Can I do it myself (the recharging)? If so, what do I use? Are there
>different grades of coolant?

Since you have a '91 I assume it uses R-12 refigerant, an ODS. In
that case... no, you can't do this unless you are a licensed
refrigeration mechanic (in which case you wouldn't be asking this).
You can't even buy the R-12 you'll need to recharge it. You will need
a pump to draw down the old system, capturing the old refigerant for
recycling or disposal, and to vacuum the system before charging it.

>How much is a rebuilt compressor going to cost me and is it worth the extra
>money over the wrecked one?
>
>Are there any other related repairs I should look at doing at the same time?

Yes (not really a repair...) be sure to have the drier replaced. It
should always be replaced if the system is completely opened.

>Thanks,
>
>Bill G
>'91 SE Auto
>166k miles

Reply to this Message

Bill G - 25 Jun 2004 06:08 GMT

Thanks for the responses.

I didn't get the A/C compressor. I'll wait 'til I have more money to spend
on it and buy a rebuilt and let someone else do the labor.

I did get a new driver's door control panel (locks/windows) while I was at
the junk yard. I haven't had a working driver's door window for quite some
time, so the trip wasn't wasted (I was going by it anyway). Got the panel
off a '90 GXE for $25. Swapped out the "used" buttons (for looks) and now I
can go to a drive thru again without having to drive slightly passed it so I
can open my door.

Bill G
'91 SE Auto
166k Miles

> Hey,
>
[quoted text clipped - 29 lines]
> '91 SE Auto
> 166k miles

Reply to this Message

Richard Tomkins - 25 Jun 2004 06:47 GMT

I am reminded about an industrial accident that occured at a place where I
worked.

On the roof of a three story office tower was an air conditioning unit. The
senior maintenance guy was up on the roof on one of the hottest days of the
summer, releasing pressure in the AC systems by unloading coolant back into
a standard refigeration tank. I don't know if the use of this type of tank
was normal, but the activity of reducing the pressure in this fashion was a
normal practise, from what I was told.

The tank thta was being re-filled exploded adn the gentleman standing over
the tank was extremely badly injured. I believe that he lost a leg and the
lower half of his body was severly hurt. He took more than year to recover,
somewhat and he was able to learn to walk again.

So, even the professionals can have issues, so inexperiencd folks shoul dnot
have a go a folling with the refrigerant system themselves.

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