The A/C on my 87 vette doesn't work well at stop lights (coolant/oil temp ~205). Seems to do okay on the highway but not ice cold like my v6 van. Does that sound like low R12? Works great when it is about 70 outside, but gets worse as the temp goes up. Also, the blower does not stay full on (even in manual mode) - it cycles - is that a clue?

I was thinking about doing the 134a conversion. Anyone do their car? How well does it work? Thanks for any info!

 

Yep...changed my 87 to R134a earlier this year.

I found two things:

1. The condensor is either too small or doesnt have enough airflow over it when the car is not moving.

2. To get the low speed cooling, you have to go low on the R134a pressure...meaning, do not overcharge it.

I solved the low flow problem by adding a second cooling fan in front of the ac condensor, but it seems to be killing my low speed battery voltage at idle.

 

I converted to R134a in my 89. I seems to work as well as the R12. I also see a difference when idling as compared to moving. I have been told that the 134 does not work as well when the system is overcharged.
I have also seen posts which recommend the evaporator in the exchange box be cleaned to improve performance.

 

How many cans of 134a did you guys use?

BBA:
I wired up my AUX fan to a switch over the weekend to possibly fix the problem, but it didn't make a difference. Are you using the Aux fan plus another fan?

 

In order for the r134a to work correctly the system has to be purged of r-12. A retrofit kit also has to be installed. It is nothing more than two screw on valves to accomodate the r134-a attachments, and some oil placed into the unit. It is also recommended that the dryer be changed as well
It is recommended that a professional a/c shop do the work. You need to have the correct amount of freon in the system for maximum results. The cost of converting the system cost me $150.00.

 

I have. I notice that it isnt quite as efficient as R12 too.

 

Well before your a/c died. Do you remember that at stop lights etc your vette just didnt cool well either. C4's have like 2000 degree under hood temps. A/c gets could when you move more then standing still. This is r-12. Now if 134a is worse mabye I should buy a 60lb tank now.

 

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:[/color]<HR><font face="Verdana, Arial" size="2">
It is recommended that a professional a/c shop do the work.
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I spent $100 total, replaced the accumulator, orifice tube, ALL "O" ring seals. flushed the whole thing with crc "Brakleen" brake parts cleaner ( it is safe to use on AC systems...leaves no residue ). I then used ENGINE vacuum to vacuum the system for about 10 minutes ( this part I really don't think was too critical...a vacuum is mostly to remove moisture from the system, and most moisture builds up in the accumulator resin...which was new in my case ).

Thats all there was too it, only took about an hour and a half to do.


<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:[/color]<HR><font face="Verdana, Arial" size="2">
BBA:
I wired up my AUX fan to a switch over the weekend to possibly fix the problem, but it didn't make a difference. Are you using the Aux fan plus another fan?
[/color][/QUOTE]

My car does not have "Heavy duty cooling" so I had NO aux fan. I went to Pep Boys and bought a 16" engine cooling fan. I mounted it on the front of the condensor pushing air into the condensor. This was NOT a fun trick, a 16" fan does NOT really fit there...I would go with a 14" next time.

I wired it to the main fan relay, which I replaced with a generic type super heavy duty relay. It really helped my low speed driving AC performance, but I still notice better AC performance on the highway.

I know the better highway performance is due to better condensor cooling, as my low pressure side pressure does not change more than 5PSI from idle to 3000 RPM. I keep it at about 40PSI.

 

I did the R134a conversion in my 85 and I used a Smart VOV. I am very happy with the system's performance. I get low vent temps and lower than stock high-side pressures. See here:

http://www.corvetteforum.cc/ubb/Foru...ML/010441.html

The system should be flushed and evacuated correctly before adding the R134a oil and refrigerant. All moisture should be removed from the system.

--rb--

 

So what about the kits they sell at say AutoZone. About $35 for the conversion... I dont want to spend an arm and a leg, would I be better off with the R12 or this kit.
Paul

 

My boss did one of those $30 conversions on his Mazda after his schrader valve went bad and leaked all the R-12 out...he did not flush or anything...and it works just fine...that was a few months ago, so who knows.

 

Ross

Who sells the VOV? I want one.