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Tuesday, June 21, 2016

Replacing A/C compressor, rec/drier, etc.on 1998 Chevy S-10

I replaced an Air Conditioning compressor on my 1998 S-10 4-cyl (2.2L engine)
pick up 3 to 5 years ago. The system is once again not working, though
the electric A/C compressor clutch kicks in OK. Pressure is nearly the
same between the high and low sides, which I believe whas what
happened before I replaced the compressor the last time.

I had replaced it with a Chinese made copycat compressor and a
receiver drier, and possibly an orifice tube (not sure about the last
item). I hooked everything up loosely and let a backyard (but
licensed) A/C mechanic finish the job with the proper O-rings, oil,
refrigerant, etc., and the job included a flush of the condenser and
evaporator coils and the connecting plumbing.

I do not know if the flush was thorough enough but I did watch him
flush the system. I plan to purchase the canister to put the flushing
fluid into to flush my system before putting the new compressor and
receiver-drier on and doing a vacuum on the system then charging it.

I would like to do the replacement myself this time. I have the gauge
set and a vacuum pump and have used it since the last time I got the
replacement done on other vehicles, including evacuating and
recharging an A/C system on a 97 Mazda Protege. I can follow
directions well enough as I've rebuilt a Honda Accord engine by
following the instructions in a repair manual and asking a few
questions of friends who have experience with this sort of thing.

First, I've found a complete parts set of a compressor and receiver
drier on Rock Auto dot com for a reasonable price. I can add less than
$100 more and get a condenser coil, but I am not sure I need it (see
next paragraph).

I have read where some of the very newest vehicles use such tiny tubes
in the condenser coils that they are near impossible to flush.
However, I don't know if they were that small in '98 or not, so I need
some input here as to whether I can just flush the original condenser
and re-use it or not???

Also, when I flush the various sections of the system, I would
appreciate knowing which hose/port and direction to flush the fluid
through, or does it matter which direction I force the fluid through
the system when it's opened up???

I don't plan to be stingy with the fluid even though it's not cheap.
If I use a whole gallon on the system that's fine with me if I need
to. But if I only need to buy a fraction of that then I can save some
money there, too. So how much of this flush fluid will I need to buy?

Does it store well when unused for a long time if tightly sealed?

I will also need to know what sort of torque to apply to the bolts on
the fittings at the compressor and anywhere else I need to be careful
about torque. I might not be able to torque the hose fittings as I
only have a wrench which will fit sockets but I am open to any
suggestions or help. This is my first A/C compressor replacement job
so I want to approach it cautiously and get whatever advice that might
be helpful. The previous replacement I didn't really do any of the
technical work, though I"ve learned about the evacuation and recharge
process and have done that successfully on the Mazda.

Any help with this would be appreciated. I've posted this to the two
groups which have helped me the most in my various automotive repairs.
Both groups have helped me in the past with my S-10, and I thank you
all for that.

I will wait a few days for replies to come in before I order anything.
If I need to buy a condenser coil also (and I'd rather not so I can
avoid the extra work of removing and replacing it in this hot summer
weather), I can get it cheaper in a set from Rock Auto.

If any of you use Rock Auto and know how to find generic items like
the flush fluid instead of me buying it through ebay (or if you have a
better source), please share that, too. I can find model-specific
parts very easily but when it comes to the generic stuff I find it
hard to find there, but I would think they would have those items too.
Thanks in advance.


  1. You do not need a gallon of flush. I can get by with 1 quart for 3 jobs. Of course if you find an excessive amount of metal shaving when you remove the orifice tube, you may want to use a little more. I would not replace the condenser, you pressure would have pegged if it was restricted. As for using torque on you hoses, no need. The O-rings are what provide the seal. Just make sure they are snug with the wrenches you have. Pour all oil from the compressor before you install it. I will suggest at least a 45 minute vacuum draw after you reassemble. Hold for 30 minutes to make sure there are no leaks. After that, make sure to add the correct amount of PAG Oil. It will suck it in the system from the vacuum. Then add your Freon. This will insure an icy cold experience.


  2. IMHO – the A/C needs to be run in the wintertime or during cooler weather frequently to allow the seals to lubricate otherwise drying up and leaking. I think in newer models the A/C comes on when in the defrost mode.

    As an aside, 4WD needs to be run for the same reason – lubrication. I run our 4WD’s at least twice a month around our acreage – been doing that, both A/C and 4WD for years and so far, no problems.

  3. Thanks to all who replied. I saved the posts and will be evacuating
    the system and doing a vacuum test as suggested, then I'll try pulling
    a vacuum for an hour after reaching ~29 inches or so (I think that was
    the maxium vacuum I got on the Mazda) and then adding 32 oz of
    refrigerant. (If the amount is different it will be on the label under
    the hood.)

    I do remember now that the Mazda had a similar symptom, having roughly
    the same pressure when the compressor was running (a minial difference
    between high side and low side) and after I evacuated the system and
    recharged it, everything was fine again.

    Does this sort of thing happen often when an A/C system in a car/truck
    isn't used for a while?

    Thanks for all your help so far. Hopefully all I'll need to do is to
    check and recharge after evacuating the system. If not, it looks like
    I have the advice I need on how to proceed after doing the replacement
    of the compressor, orifice tube, etc.

  4. OK, here's where I am with this mess.

    I evacuated the system and it held a steady vacuum for 1/2 hour or
    more around 29 in mercury. I then added 134A refrigerant 1 can at a
    time. Somewhere into the second can the compressor cycled on twice or
    three times, briefly though, and it never did again. And when it did
    cycle on for 10 seconds or so a few times, the high side didn't go up
    much, and the low side stayed very high, like around 80. It seems
    something is amiss.

    All the while the pressure on the low side went up slowly to 95 and
    the high side to 100 while the engine was running. The compressor
    isn't kicking in anymore. I started on the 3rd can but it doesn't seem
    like it's taking the refrigerant at this point.

    Is it time to replace the compressor, receiver-drier, and orifice tube
    after flushing the system and starting fresh?

    The compressor was new, not rebuilt, but it wasn't a genuine Delphi
    compressor like the factory one.

    If I do end up doing a replacement of components, where can I get the
    flush in an aerosol to save me from buying the canister that you put
    the flush liquid in and pressurize it with air?

  5. The AC compressor has numerous moving parts (containing pistons and valves). These interior parts can fail, causing the AC compressor to stop functioning. It is common for the interior parts of the compressor to come apart and diffuse metallic debris throughout the system. Therefore, it is a requirement to swap the orifice tube and the receiver dryer when replacing the compressor since some of the debris may have ended up there.

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