I know, its kinda late in the year to be thinking about your A/C. Sorry, but it takes me a while to build a webapge.

This is an instructional/picture series of a 134a retrofit I completed on my fiero. I've done 5 of these so far with no problems.
http://www.geocities.com/FIEROWAREHOUSE/134aconversion.html

If anyone knows of anything I forgot, or knows a faster plan for retrofitting, please let me know.

Well, it's about time you got that site together

Of, course your right, not that we need A/C at this time of the year.

Looks good, and I'm sure it will be helpfull!

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hoop
Red '86 GT

Very Nicely done. When changing to R134 you may also want to adjust the low pressure switch on the accumulator. Usually the compressor will cycle too often if left at the r12 cycle pressure settings. It is set to cycle between 25 and 45. drop it down about four to 21 and 45. To do this, unplug the switch to the accumulator and you will see a flat head screw. turn counterclockwise about a 1/4 of a turn to lower the setting.

You need a working A/C system all year round. Don't forget that the defrost/defog setting runs the A/C in order to pull the humidity out of the air.

The "filter" you refered to in a few places is the "orifice tube". It should have been replaced. They are only about a 3-6$ part. That thing can screw up the whole system. Orifice tubes aren't ment to be cleaned. cleaning can screw up the metering holes in them.

some of that oil should have gone directly into the compressor. If you don't drain the comressor there's still mineral oil in the system.

The way the compressor is done is to pour out the old oil into a measuring cup. then pour an equal amount of new oil into the comressor. (Suction port)

I'm not sure why you put oil into the evaporator. There are no moving parts there. It will only pool in the bottom untill the refrigerant eventually carries it away. Oil into the accumulator was correct.

I'd also put a note about disconnecting the compressor before flushing.

[This message has been edited by theogre (edited 10-30-2000).]

wwh0001
Thats interesting. Never thought about adjust to compensate for pressure difference. Never had a problem with cycling though.

Ogre

Filter/expansion valve/orfice tube. Yep, replaced it. Stupid not to. Plus removing it shows the " life history" of the compressor.

I followed the instructions in A/C manual from library. No mention of removing oil in compressor at all. It did mention I could pour 2 oz into compressor if I wanted, but not necessary.

Per instructions, oil in evaporator was needed. During the evaporator flush, alot of oil came out.

Will add your suggestions when I update........Thanx.

Is there anyway to flush the mineral oil out of the accumulator? If so, then you should be able to place the flushed accumulator in the oven on low over night to dry out the desicant and "renew" it. Granted, not as good as a new one but pretty close? Just curious cause a new one costs me $54 and if I can flush it with a couple of dollars worth of mineral spirits or alcohol then I save $50. I've already converted to R-134 and it cools very well nad has no leaks without any system flush or parts change. I just vacumed for an hour and added ester oil and R-134.

Its like a maze inside the accumulator. I doubt you'd could drain all oil out.

bummer...I was hoping for a cheap and easy flush (anyone have an internal diagram?). The more oil I can remove, the less benefit a new accumulator provides. Many conversions that are done don't even replace the accumulator and still cool just fine, such as my '85 Volvo 740 and '88 Fiero (my current cycling and fan problems seem to be pressure switch related). The mineral oil is not compatible with R-134 but it is not reactive either. Any remaining mineral oil just settles to the low spots and "dead" spaces it can find when you do a conversion, or so I've been told.

Doug, the manual likely wouldn't nessisarily cover draining the compressor unless it specifically was dealling with a covnersion. In a conversion you definatly want to get out whatever was in the compressor sump. Most replacement compressors I've seen also tell you to pour X ounces of oil into the compressor suction port.

Tom88 The problem isn't just the oil but the desicant itself. The old desicant is designed to last 7-8 years and is not happy about R134. The new accumulators all have a R134 friendly desicant that is happy with either R12 or R134 charging. The rule on desicant has always been to replace it any time the system is evacuated after age 7. It's not just a conversion issue.

Trying to salvage an accumulator could weaken the desicant pack which could cause it to rupture and contaminate the whole system after charging. If desicant reaches the compressor you can likely kiss it bye bye.

[This message has been edited by theogre (edited 11-01-2000).]