Automotive Air Conditioning Information Forum (Archives)

caveeagle on Fri July 15, 2011 4:59 PM

Year: 2000
Make: Cevy
Model: Mark 3 Conversion
Engine Size: 4.3
Refrigerant Type: R134a
Country of Origin: United States

Our van has had a slow leak for a while now and last month the compressor completely froze up. This caused the engine to stall on my daughter. With the ACoff, it the car drives just fine, so I assume that the forzen compressor is what caused the engine to stall.

It has an aftermarket rear AC system from ProAir that was installed by Mark III.

I am short on cash and have always been pretty good at DIY automotive repairs. I have always wanted to learn more about auto ac, so now is a good time to dive in. I think the system had some sealant injected at some point (I know,I know), so i deffinately need to get a good flush on the system.

I am planning to:
>get a new (not rebuilt) compressor
>replace the dryer accumilator
>replace the orifice tube (front)
>Replace the expansion valve (for rear ProAir system)
>Replace as many of the Oring seals as possible
>flush out the system before assembly


A few questions as I am collecting parts...

>ProAir tells me I need a #38683 expansion valve for the rear system. Where is the best local place to find this? I did not find it on the NAPA website.

>AAP stocks AC Delco and 'Factory Air' parts. Anyone know which is better?

>should I replace the pressure switch that screws into the dryer? Is there more that one switch? AAP lists 2 or 3 on their site. ??

>can I flush the condensor on this car? I have found conflicting results to this question on the web?

Thanks!!

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mark

bromodragonfly on Sat July 16, 2011 1:16 AM

I would search google for that TXV and order it online. Or find the exact brand and model, and phone a wholesaler to see if they can reference a suitable replacement.

Can't help you much with advice on which brand is better, sorry. I've used AC Delco switches, orifice tubes, and driers, they seem to work fine.

No need to replace the pressure switch unless it's not working correctly. People seem to refer to an accumulator, drier, and receiver all as the same component, so depending on what you're talking about, it could be the high pressure cutout or the low pressure cutout.

Someone else will know more about the style of condenser than I do.

Hopefully you have a decent vacuum pump, gauges and a scale. Otherwise you may end up buying new parts in a year from now, which will nullify the money you're going to save on labor. But good luck, it will be a learning experience.

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There is no knowledge that is not power

caveeagle on Sat July 16, 2011 6:30 AM

"Hopefully you have a decent vacuum pump, gauges and a scale. Otherwise you may end up buying new parts in a year from now, which will nullify the money you're going to save on labor."
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I have a set of guages and a vacum pump i purchased from Harbor Freight last year. I know they are not of the best quality, but they seem to work well enough for DIY service.

I do not have a good scale. Is this absolutely needed? I was planning to calculate the needed amount. I know it needs 3 to 3.5 lbs of R134a. So I planned to fill with 4 12oz cans to start with and add a little if needed to get the temp right.

I can get a scale to use if that would be a better way to measure.

Since the rear system is an aftermarket conversion, I am not completely sure how much it needs, so using the temp method might be better.

I think all the switches are currently working fine. Before the compressor failed, it was cycling on/off a lot, but I think that was a function of low refrigerant and a dying compressor.

Also, I know how to do a vacum test on the system before filling. Can anyone direct me to a good write up on how to do a pressure test with compressed air?

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mark

caveeagle on Sat July 16, 2011 6:33 AM

Also, I found the expansion valve locally at AAP. Turns out it is the same part used on a '79 F-100, to I can get it locally this weekend. It will cost a little more than ordering online, but timing is also important this time.

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mark