You can find the pressure charts for that car with for R134a at
http://www.honda.co.uk/owner/civicmanual/pdf/22-20.pdf.

R134a (1,1,1,2-tetrafluoroethane) is a larger molecule than R12
(dichlorodifluoromethane) so I would imagine that the expansion valve
should be larger to accommodate that. Was it replaced when you had the
seals etc. replaced?

Steve wrote:
>
> I have a 1992 honda civic that used the old school R12 refrigerant. My
> brother a few years back did a motor swap on the car and of course swapped
> out the compressor for the a/c at the same time. The new compressor is off
> a brand new car so its r134a compliant. To get the a/c working again he
> took the vehicle to a shop that supposedly changed out the seals and
> evacuated and rechraged the system with r134a refrigerant.
>
> All was working well up until this spring when my a/c stopped working.
>
> I recharged the system with a set of brand new gauges and genuine virgin
> r134a refrigerant. All was working well up until my curiousity uncovered
> something quite interesting.
>
> My a/c blows about 10-12 degrees celsius which is acceptable for ambient
> temp of about 20 degrees celsius. I decided to hook up a set of gauges to
> my car and found the readings to be quite off from what I think they should
> roughly be.
>
> The low side suction pressure is about 23-28 psi and the high side is at a
> crazy 250-260 psi! The line to the condensor is extremely hot which i
> already know is not normal. The car cools reasonably well so I'm lost as to
> what could be wrong. According to my honda service manual a excessive high
> discharge line pressures and abnormally hot condenser lines indicates a
> restricted refrigerant flow in the system.
>
> here are some observed items:
>
> 1. the receiver drier is the original R12 receiver drier (the shop was
> stupid enough not to change it out to comply with r134a)
> 2. There is a small refrigerant leak from the acme fitting on the low side.
> 3. The discharge line into the condenser is insanely hot
> 4. The suction line is noticably cold
> 5. the receiver drier feels very warm to the touch and the line going to
> the evaporator is also very warm to the touch.
> 6. The ambient temperature isn't hot enough to make the suction line to
> sweat.
> 7. The high side pressure before starting the car is only at 90 psi. As
> compressor run time increases the higher the pressure and the higher the
> condenser line temps.
> 8. When the compressor cycles on and off the high side pressure can
> fluctuate as much as 25-30 psi. When the compressor pumps the pressure
> shoots up very fast and when it stops it drops fairly rapidly down about
> 20-30 psi before really coming to a stop. After the cycle starts over again
> with discharge pressures getting higher and higher.
> 9. I highly doub the system is overcharged b/c the low side pressures are
> so low.
> 10. The compressor i am using is brand new straight from honda.
>
> With ambient temps on the cooler than average side and a discharge pressure
> so high I can only imagine what the end result would be when the ambient
> temp shoots to over 30 degrees. My a/c would literally explode!
>
> I can't see how the system is restricted other than two places. The
> expansion valve or the receiver drier.
>
> The expansion valve couldn't be stuck closed b/c I get a decent amount of
> cooling
> The expansion valve couldn't be stuck open b/c the evaporator doesn't freeze
> over
> The receiver drier is the original r12 drier so that should be an obvious
> sign of bad a/c retrofitting. I will change that out
>
> I was good at fixing R12 a/c systems in older cars but this retrofitted
> civic is a tough one to figure out. I don't want to take it to honda and
> spend 500 bucks to fix it when I have all the equipment to do it.
>
> Can someone tell me what the heck is wrong?
>
> Thanks