Automotive Air Conditioning Information Forum

I have vacuumed this system out, I put the recommended amount of 134a in the system which is 450 grams. The system was working before I repaired a hole in the condenser, now I can't get below 75 degrees measured temperature on the cold pipe with 50 psi on the low side. I have approx 230psi on a 90 degree day.

Hitting the condenser with a garden hose drops the high pressure but leaves the low side unchanged.

I have good air flow on the evaporator, and when I read the engine I get the low side to dip down to about 25psi but the pipe temp doesn't change.

2006 smart fortwo
0.8L diesel
Canada

Any advice would greatly help me out.

You have 230 PSI on the high side on a 90-degree day, which sounds about right. I'm confused about the 'cold pipe" and low-side pressures of 25 and 50 PSI. I don't think you mentioned what the vent temp is, but I assume it is higher than you'd like. Did you replace the condenser with a new one or just repair the hole? What do you mean by "read the engine?" Is this a CCOT or TXV system?

Sorry.... Not "read" the engine..... It should have said "when I rev up the engine" auto correct turned rev into read.

I don't know what a CCOT or a TVX system is.

I welded the hole closed in the condenser to get it working until the new condenser gets here from Europe.

The vent temperature is sitting around 80F

In other vehicles I have fixed I have got about measued 35F on the pipe with about 8 degrees of super heat. This little car isn't even close

I pulled the heater box apart and found the evaporator is clean and clear and the cabin filter I pulled out for now until I fix this problem.

Scampo77 wrote:Sorry.... Not "read" the engine..... It should have said "when I rev up the engine" auto correct turned rev into read.

Got it. Happens to me as well

Scampo77 wrote:I don't know what a CCOT or a TVX system is.

Clutch Cycling Orifice Tube, or Thermostatic Expansion Valve

Scampo77 wrote:I welded the hole closed in the condenser to get it working until the new condenser gets here from Europe.

That might be part of the problem, especially if any debris found its way in and/or if the repaired area is still leaking a little.

Smart cars like your year and model are known to have persistent refrigerant leaks. Are you sure that you still have 450 grams (15.9 ounces) in it? Because this system holds so little refrigerant, just a couple of ounces lost will result in performance issues. Maybe the hole repair is still leaking, or it could be losing refrigerant someplace else that you haven't noticed yet. Revving the engine and seeing the low pressure drop like that could mean a metering device issue (CCOT or TXV, whichever it has).

One other thing: I strongly advise against using Red Tek or DuraCool in it and staying with plain old R-134a. I believe that these products, readily available in Canada, are essentially propane (highly flammable!), and might also contain sealer. You definitely don't want any sealer in your A/C system.

In the USA, we don't normally evaluate a mobile A/C system using superheat and subcooling. We generally leave those methods to the residential/commercial HVAC techs. Charging by weight using the proper refrigerant and an accurate scale, measuring / evaluating high and low pressures, and gauging vent temps is essentially the way we do it here. So I'm a bit out of my league with the former.

At this point, I think I'd wait until the new condenser arrives. Then, recover whatever refrigerant is in there, install the new condenser, along with a new receiver/dryer and all o-rings, evacuate well, recharge to spec with plain R-134a, an ounce of the appropriate oil, and a little UV dye. With the dye pre-installed, you can then leak-check the system later if you discover that it's still losing refrigerant.