Honda Accord 1996 A/C R12a Refrigerant to refill R134a

Hi,
In the past two years my A/C system been checked twice for leaks with negative results that is, they couldn't find the leak point. They'ld refilled it with R134 (by an amount of 24 oz) and with that the A/C would work for the rest of the summer. The August of 2004 was the last time I had my A/C checked and once again, this summer, the A/C is not producing cold air. Assuming that the leak is small and that this year too I have only lost an amount of the refrigerant similar to last year (24oz) I bought the RedTek 12a Recharge kit (which contains 2 cans, each equivalent to 16 oz of R134a). I did not realize that the refrigerant in my system was R134A and as they say is it illegal to mix it with a different type like the R12a I bought.
The literature I was able to find in the internet site for RED TEK says: DO NOT MIX REFRIGERANTS. Mixing refrigerants is illegal in Canada and the US ...
My questions are:
Does anyone know the total amount of refrigerant in the A/C system for the 1996 Honda Accord 2.2L?
How can I measure the amount of refrigerant lost?
Why is it illegal to mix refrigerants when they say that the R12a is compatible with most existing refrigerants?
Should I first have the A/C system checked again by a certified garage and request that it is refilled with R12a so that next year I can refilled it myself in case it leaks again?
What are the risks of mixing R134a with R12a?

I will appreciate any help.

Regards

G.

  gulilero

If the car was designed for R-134a, use 134a

  tbaxleyjr

the number of oz. the system takes should be on a sticker on the hood. 3lbs or so?

  carls47807

It says it is compatible because it contains the same oils as R134a, but I wouldn't use it if your car already takes R134a (which it should) since R134a is readily available just about at any parts store. R12a is mainly used as a replacement for r12 (freon) which has since been illegal to use without a license (and it's about $30 a can as opposed to $10 a can for R134a). You don't want to mix refrigerants because some formulas contain different oils which can damage your a/c unit and the system will not offer the maximum performance of your system. R12a contains the same oils but Redtek actually recommends a full evacuation of your system prior to filling with r12a.

P.S> for a 1994-97 Accord it is 650 grams (23 oz.) refrigerant to fill

  97Talonchik

and an extra 2 oz per hose on the evac refill machine ;) dont forget that it sux having to go back:( is r12a common where you live cuz all it is here is r134a

  BanffAutoSpa_ap

one can recharge 134a without a certification card but one has to have one to remove any refrigerant (a reclaim machine must be used) as well as to buy any quantity of R-12

  tbaxleyjr

i would try to find that leak. i was reading the redtek website.. it says u need to charge the system to 33% of r12 capacity. its gonna be hard for u to find a shop that service this gas.. remember if there is a leak, air got in. ur cooling wil be limited.

edit: oops. u need info on amount compared to r134a.. http://63.135.115.175/techinfo_char_wt_charts.html#
6oz = 1 lb of r134a

  thongsai