Does one of the San Antonio members have a set of R-134a A/C gauges I can borrow?

I got my parallel flow condenser installed and even though it's 100 degrees and even though it's R-134, I expected better performance.

I had it vacuumed and charged on Saturday. They tested it with a large capacity fan blowing across the front and I could only get down to about 52 at the vents. On the positive side, the coolant temp didn't go above 80 degrees.

They hooked up the low pressure side to the machine and said it was pulling about 30 psi, which is probably too low. They did not put the hi-pressure side back on. I think the chart for the low side at 90 degrees ambient said it should be about 50-55 psi. The tech said he had a similar problem with an older Ford and he had to swap expansion valves three times before he got one that opened/closed to get good cooling.

At about 60 degrees outlet temps there was a fair amount of froth/foam in the sight glass, so the tech added two more ounces 134 on top of the 2.2 pounds since it wasn't cooling as expected. The froth disappeared and the cooling improved for a few minutes and dropped the temp to 52, but then the clutch started cycling. I presume the high pressure cut out (HPCO) was kicking in.

I suspect the expansion valve (newly replaced) may be limiting the refrigerant flow and creating too large a pressure difference between high and low sides: not enough refrigerant to cool, but too much pressure and the system cycles when set to Min.

Before I have my system evacuated again for an inspection of debris/crud in the TXV, I'd like to know what's happening with the pressures.

Other info: this is for a fully flushed system on an '83 300CD using a new compressor, new PFC, new R/D, 8 oz fresh PAG oil.

I am sure some one like Larry Bible would have the gear, but .....

__________________
Grumpy Old Diesel Owners Club group

I no longer question authority, I annoy authority. More effect, less effort....

1967 230-6 auto parts car. rust bucket.
1980 300D now parts car 800k miles
1984 300D 500k miles
1987 250td 160k miles English import
2001 jeep turbo diesel 130k miles
1998 jeep tdi ~ followed me home. Needs a turbo.
1968 Ford F750 truck. 6-354 diesel conversion.
Other toys ~J.D.,Cat & GM ~ mainly earth moving

I bought mine at HF $34 on sale. At that price, not worth it to run around borrowing (for me anyway).

One thing with the HF manifold set, pressure test it before use. I did that and found a sticky schrader valve on the charge port. Took it out and lubed it and then it sealed.

__________________
85 300D turbo pristine w 157k when purchased 161K now
83 300 D turbo 297K runs great. SOLD!
83 240D 4 spd manual- parted out then junked

Sorry Yak, I have a set,but they are R12., and As I recently found out...not as easy as just getting a hose set and screwing it on....

(Also I'm at Port A right now, so not really in SA at the moment...)

__________________

Current Mercedes
1979 maple yellow 240D 4-speed

Gone and fondly remembered:
1980 orient red 240D 4-speed

Gone and NOT fondly remembered:
1982 Chna Blue 300TD

Other car in the stable:
2013 VW Jetta Sportwagen TDI / 6-speed MT

an r12 set can be used if you purchase the adapters for the ends to go on 134 fittings. you will need 3 adapters, hi, low, and the tank adapter should be 1/2" female acha or something similar...

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John HAUL AWAY, OR CRUSHED CARS!!! HELP ME keep the cars out of the crusher! A/C Thread
"as I ride with my a/c on... I have fond memories of sweaty oily saturdays and spewing R12 into the air. THANKS for all you do!

My drivers:
1987 190D 2.5Turbo
1987 190D 2.5Turbo
1987 190D 2.5-5SPEED!!!

1987 300TD
1987 300TD
1994GMC 2500 6.5Turbo truck... I had to put the ladder somewhere!

If you want to get these, you can borrow my set. I will be back in SA this weekend.

__________________

Current Mercedes
1979 maple yellow 240D 4-speed

Gone and fondly remembered:
1980 orient red 240D 4-speed

Gone and NOT fondly remembered:
1982 Chna Blue 300TD

Other car in the stable:
2013 VW Jetta Sportwagen TDI / 6-speed MT

Here are some threads with PF condensers to read through. Seems like stepped ports are troublesome to some. Did you check for leaks since system was charged?

My Parallel Flow "Condensa Advencha"

AC manifold vs compressor vs seals vs my brain pan

1982 300TD R134a conversion with parallel flow condensor update!!

parallel flow condensor installed in a W123

__________________
85 300D turbo pristine w 157k when purchased 161K now
83 300 D turbo 297K runs great. SOLD!
83 240D 4 spd manual- parted out then junked

Too hot in the garage and too many other things going on. It's sat there since Saturday.

I got a set of HF gauges - cheap and you get what you pay for. The thumb knob is already broken after one use.

But I got my data from them. Conditions - car sat overnight, tested at about 85-90 ambient.

Static/ambient pressure - 110 psi on both sides. I presume no leaks due to the high pressure and no evidence of oil anywhere.

I took it for long highway drive @ 70 mph. Outdoor temps at about 95-100 this afternoon. Vent temp cooled to about 58 degrees and never got any colder.

Checked pressures immediately after getting home

48 low
245 high

No real changes with significant throttle changes. The aux fan was on, but I did not use any supplemental fans to get airflow across the condenser. Some bubbles/foaming in the sight glass but I've read that's not unusual with 134 and doesn't carry the same impact as bubbles in R-12. The clutch behaved itself, no cycling or other issues.

These are in the ballpark according to the ackits chart for 134 - http://www.ackits.com/aacf/ptchart.cfm

I've cleaned the evaporator before, so I'm getting good airflow and the monovalve is behaving itself since I get near ambient without the A/C on. I don't think I've got any other A/C related malfunctions in the flaps. Vacuum is all good and doors, seatbacks, etc all work normally.

I'm thinking about taking it to the pros to see if there's something I'm missing. I should have been able to get better than 58 degrees with 134 and a parallel flow.

Maybe longer on the vacuum to ensure all moisture is out, then start filling by pressures instead of weight? The difference in volume in the PFC may have made the initial charge too high?

X2 on longer vacuum

The 240d was performing like that. Like you
I knew there were no leaks, so I vacuumed for a few hours then refilled with 80% of the indicated R12 volume.

Now it goes down to 40-45* at center vents.

I think there was some air that the vacuum removed.

__________________

Current Mercedes
1979 maple yellow 240D 4-speed

Gone and fondly remembered:
1980 orient red 240D 4-speed

Gone and NOT fondly remembered:
1982 Chna Blue 300TD

Other car in the stable:
2013 VW Jetta Sportwagen TDI / 6-speed MT

X2 on longer vacuum

The 240d was performing like that. Like you
I knew there were no leaks, so I vacuumed for a few hours then refilled with 80% of the indicated R12 volume.

Now it goes down to 40-45* at center vents.

I think there was some air that the vacuum removed.

__________________

Current Mercedes
1979 maple yellow 240D 4-speed

Gone and fondly remembered:
1980 orient red 240D 4-speed

Gone and NOT fondly remembered:
1982 Chna Blue 300TD

Other car in the stable:
2013 VW Jetta Sportwagen TDI / 6-speed MT

Those pressures are different (higher) than on my VW where I replaced condenser and dryer and charged with R134. Low 30 psi, high 230 psi on a 85 F ambient day with vent temp of 39 F.

Do you think the parallel flow has smaller volume than the old condenser? Did you put in less freon because of the reduced condenser volume? Try letting some freon out and see if the pressure drops and vent temp gets colder. It's illegal to vent R134. But each time you hook up the gauges you lose some refrigerant, so take as many readings as you need till you get to the desired pressures/ vent temps.

__________________
85 300D turbo pristine w 157k when purchased 161K now
83 300 D turbo 297K runs great. SOLD!
83 240D 4 spd manual- parted out then junked