Automotive Air Conditioning Information Forum

1998 civic had poor cooling so, system was recovered and evap, txv, and blower pulled. Evap and blower were covered in leaves and organic sludge. Evap and txv were coil cleaned and flushed. Condenser was also coil cleaned. System “seemed” to have excess oil and dye so, evap & txv were put back without oil. System held vacuum so, r134a was weighed back in.
System is not cooling. High pressure port and hose to condenser are ultra hot. Low pressure port and hose are NOT cold.
Pressures are:
LP: 10-15 psi
HP: 250 psi

Some questions to help start us on track to a diagnosis:

What was the ambient temperature, preferably one foot in front of the condenser, not the weather forecast?
How were the pressures measured, under maximum load or at idle?
How did it "seem" to have too much oil?
How much refrigerant was weighed in?
Was the receiver/dryer replaced?
Original TXV?

Amb @ 1ft.: 91.4F
LP: 15 psi @ idle
HP: 175 psi @ idle

LP: 5 psi @ 2000rpm
HP: 280 psi @ 2000rpm (psi goes higher as rpms goes higher)

23oz weighed in w/ scale
Receiver/dryer was not replaced.
I believe TXV is original.
System seemed to have excess oil because more of it sprays out when connecting/disconnecting gauges than I’m used to. I also know that it’s a frequent issue when owners add canned refrigerant. I may be saying this because of the dye.

Any help is sincerely appreciated.

If you are sure you evacuated and charged properly, I'd guess you have a stuck TXV. Sounds like you have huge superheat at evaporator out / suction pipe. This creates even bigger superheat at condenser out.

Air in the system kind of acts the same, displaces liquid R-134a in the liquid line, choking off TXV flow, and compressing air is a really hot process, much hotter than compressing R-134a. So if you are not sure about your evacuating and charging methods, might have left air in there.

I would flush and then start over with a known oil amount, new receiver, new TXV, evac, weigh in R-134a.

The pressures at idle really don't tell us much, so let's look at the pressures recorded at 2,000 RPM: The high side is high and the low side is very low, suggesting a malfunctioning TXV. Is the bulb of the TXV's sensing tube secured tightly to the outlet pipe of the evaporator and covered with Prestite, a black, sticky, tape-like material? Is the high-side line hot to the touch right up to the TXV and then ambient or room temperature right after it?

I also suspected the TXV. I did not suspect trapped air. Had the pump on for an hour, but there may be multiple issues that could cause the air to be trapped. Will replace drier, TXV, and flush since the parts are relatively inexpensive. Have a few questions:

1) What’s the best way to remove the oil from the compressor? Will it have to be removed from car and put on bench?
2) Are reputable aftermarket parts (Four Seasons) okay to use? Or, are there some components that must be OEM such as the TXV?

Will report back.

Many thanks.

I see lots of DIYers that don't understand how to purge or evacuate hoses and manifolds, it takes some care to be sure that what's in a hose or manifold is either refrigerant or a vacuum.

If you must drain a compressor, tipping it ports down and turning it over by hand is OK for fixed swashplates, scrolls, vanes. Variable swashplate types are more complicated.

My opinion is Four Siezens is not reputable, aftermarket new compressors are OK. For my money, I'd take a low mileage junkyard original compressor before I'd take a "rebuilt". I've seen what it takes to build a proper compressor, and I can't believe "rebuilt" compressors sell as well as they do, but I guess stop-leak does OK too, so it shouldn't be too surprising.

DetroitAC wrote: ↑Fri Aug 13, 2021 6:36 pm I would flush and then start over with a known oil amount, new receiver, new TXV, evac, weigh in R-134a.

At this point, we really don't know how much oil is in the system. So I agree with DetroitAC that you should essentially start from scratch: Solvent-flush the condenser (or better yet, just replace it), solvent-flush the evaporator, flush the compressor a few times with DEC PAG oil only--no solvent, and solvent-flush all the lines and hoses. However, those with mufflers can't be flushed and will have to be replaced. Make sure that you blow-out all traces of the solvent from each component. Any air and moisture in the re-assembled system will be removed during the evacuation process.

Bugman1400 wrote: ↑Sat Aug 14, 2021 7:09 am 1) What’s the best way to remove the oil from the compressor? Will it have to be removed from car and put on bench?

I believe that your compressor is a fixed-displacement type with a clutch, so draining and flushing it is relatively straightforward although you will have to remove it from the car. Tip the compressor over and drain it through both ports, rotating the shaft by hand as you do so. If you're curious, measure the oil that comes out. But since you're refilling it from empty, measuring isn't crucial. Then, refill it through the ports with about 4 ounces (or whatever it will take) of fresh DEC PAG-46, rotate the shaft about a dozen turns, and drain it out. Do this three or four times to ensure that you get out all the old oil and any debris.

Bugman1400 wrote: ↑Sat Aug 14, 2021 7:09 am 2) Are reputable aftermarket parts (Four Seasons) okay to use? Or, are there some components that must be OEM such as the TXV?

During the past several years, I have used different brands of aftermarket TXV's, several of which turned out to be defective after installation, requiring that they be removed and replaced a second time--not my idea of fun. For those reasons, I recommend installing only a new OEM TXV. OEM parts usually cost more but are worth it, I believe.

The specs for your car indicate that it came from the factory with either a Denso or Sanden compressor. It's important to know which one you have because the oil amounts are slightly different. The Denso compressor takes 4.7 fluid ounces of PAG-46 while the Sanden takes anywhere from 4.3 (min.) to 5.0 (max.) fluid ounces of the same oil. The refrigerant spec is the same for either compressor: 22 ounces net weight of R-134a. If you have an under-hood sticker with different specs, the sticker takes precedence.

I would distribute the oil among the components as follows: One ounce each in the condenser and evaporator, 1/2-ounce in the R/D, and the rest in the compressor.

John:

In those years we were still seeing some dealer installed A/C. Factory cars had the TRS 090 scroll compressor, Dealer air had the piston compressor.

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Thanks for that. It'll be interesting to learn which one this car has.