Re: [E28] A/C fix needed

[alex.fadeev@xxxxxxxxxxx]

"Aaron and Aimee Ness" <aaness@domain.elided>
>
> My 528e seems to have a bit of a problem with the A/C - the compressor
> engages, but I don't get cold air. [...] We hooked up the gauges,
> expecting to add some of that magic juice, and

Aaron,
If you ever decide to put some woodoo gasses into your AC system, do
yourself and your mechanic a big favor by clearly labeling what you put in
there. Otherwise you run the risk of contaminating the AC recharging
equipment of the shop that will work on your car in the future and being
handed the tab for $5-15K replacement/repair.

> although I don't recall the numbers (it's been about a year), it was
> reading higher than expected on the high side, and lower than expected
> on the low side, indicating a potentially clogged expansion valve.

Sounds correct.

> I talked to a reputable A/C shop and was given a price of ~$500 to
> replace the valve (assuming that is the problem),

On an E30 this is a $40 part that takes at most a 3 hours to replace. I
would expect something similar for the E28.
2 pounds of R12 at $50-75/pound will bring the labor to $310-360.
Depending on where you live this is either a tad high or about double of
what's reasonable.

> suck out the R-12 (they won't give a credit for R-12 removed),

Thieves.
Start looking for a new shop NOW.

> evacuate the system, and refill with R-12.

If you open the system up you owe it to yourself to upgrade to R134a. The
cost of draining/refilling the compressor with new oil and swapping the
switches will easily be covered by the cost of 2 pounds of R12 alone.

> I believe they also recommended replacing the receiver/dryer,
> although the PO had it replaced at some point in the last few years.

Drier should be replaced each time the system is opened for any significant
length of time (~30 minutes).

> So now my questions:
> First, if I proceed with this work, how can I be sure nothing else
> is in the system to clog the expansion valve once I'm done?

Not really.
Something had clogged it in the first place. On a 15 year old car that is
not unusual, but if you have a failing seal or some crap in the system it
may clog the new valve again. Make sure the NEW shop thoroughly flushes the
system before converting and filling it up with R134a.

> Second, how hard should it be to find a shop that will give me credit
> for R-12 they remove from my system?

Any decent shop will give you credit for your existing charge.
Period.

> I have a hard time just giving it to them, and then turning around
> and paying them $60/lb. for more.

As well you should.

> I should note that I won't be going to that shop since I have moved.

Good.
Ask around among your local CCA members for AC shop recommendations.
You are the club member, right?

alex f

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