I hosed down the condenser in my car today to see if it improves my ac

What I realized is that the water didn't dry on some certain spots like the rest of the condenser. The top and the sides were still soaking wet while the rest of the condenser had dried up.

Could this be evidence of an internally clogged condenser?

I figured since those parts weren't dry it meant that they weren't getting as hot as the other parts, meaning hot liquid/gas was not flowing through them.

I also noticed that my low side gauge went down from around 55psi on idle rpm (600-800) down to about 45psi and the cooling at idle improved.

I am trying to solve a problem of low cooling at idle and I'm thinking the compressor is weak now or maybe the expansion valve is stuck open from my research, but this condenser hose down today is leading me to believe I also have a condenser problem or maybe it's my only problem who knows.

Do you guys think that the condenser is clogged? Thanks for the help

  • Welcome to Motor Vehicle Maintenance & Repair! As far as the condenser being wet in certain places, did you consider where the fan pulls air through? It could be drying directly in front of where the fan pulls air through and leaving the rest wet. Did you check both sides of the equation? You said you checked the low side and it showed to be 55psi, but then went down to ~45 ... you didn't state what the high side was reading. Also, was the pressure change you stated when the compressor kicked on? Depending on the ambient temperature, those pressures don't look terrible. Dec 7, 2021 at 19:06
  • Hi, thank you so much for your response. The condenser was indeed dry where on the circular hole where the fan pulls through, but it was also dry on the left side where the high pressure gas line enters. The side that was wet just stayed wet for up to 5 minutes. Isn't that weird? Even if it was not directly in front of the fan, it should still be somewhat hot. Also the top 3 rows of the condenser aren't hot at all. I am not really sure how condensers are built. Maybe those top 3 rows are normally unused, but when I put my hand there it is always soo cold.
    – charlie
    Dec 7, 2021 at 19:15
  • 1
    Do you have any reason to believe the condenser might be clogged? Generally the orifice tube is the first thing to get clogged. The condenser has relatively wide passages and I can't imagine how it would get clogged but still have the system mostly work.
    – jwh20
    Dec 7, 2021 at 19:16
  • @jwh20 - Very good points. Dec 7, 2021 at 19:18
  • the car uses an expansion valve, and I've seen it clogged before were my low side gauge, the only gauge i have, went down into a vacuum. I googled it and found it was a possible expansion valve blockage which indeed it was. I just suspect that the condenser is plugged because the wet spots after 5 minutes looked almost like a country map. You could see a huge wet spot that remained for up to 5 minutes and I was like, this water should have evaporated by now. Even the right side round tube on the condenser, were that bag goes, was a bit hot and no way water would stay on that beyond 2min
    – charlie
    Dec 7, 2021 at 19:19

1 Answer 1


Think of vehicle ac systems similar to super or turbo charging. Are you familiar with all three systems to diagnose, troubleshoot and make repairs. Vehicle ac systems work the same as refrigerators, while house air conditioning, building hvac and walk in freezers. Are you capable of ac repairs? In my personal opinion as a diyer with experience, 98% of all vehicle ac system issues are the leaks no one wants to address but will quickly run to the auto store for refill kits, effectively refilling......a leaking system. Sealer doesn't work and ruins ac systems. Once you use any pressure gauge on your ac system, you're the ac repairman. Unfortunately, your clues points to a loss of refrigerant, a leak and not a condenser coil problem. Condenser coils work by cooling off heated refrigerant so water spraying actually helps, not impede condenser cooling. Water as a medium absorbs heat better than airflow thru radiators and condenser coils. GM uses dye at factory assembly to make it easier for anyone to find leaks using an inexpensive uv blacklight. A tell tale indication of dye is examining the two service ports. Refrigerant (invisible), oil and dye are the only things in vehicle ac systems. Dye can be yellowish green or any other day glow color in service ports in addition to refrigerant oil. If you have factory dye in your system, a uv light shined everywhere on the ac system should reveal where a leak or leaks occurred. At best, if leaks aren't found then the system leaked gradually from the front compressor seal or service ports from loose caps or worn Schrader valves. In summer, standby pressures (ac off) should be close to outside temperatures as a rough guide. Refrigeration gauges are used to determine the state of health, not one gauge on the low pressure side. Many unscrupulous dealers and repair shops prey on anyone unfamiliar with ac repairs to convince them compressors fail when its all about leaks. Compressors don't fail in general but a sealed system made largely of aluminium and rattled on every pothole takes a toll on eventual damage. Leaks are the first to occur.

  • Hi F Dryer, thank you for your comment, it is much appreciated. Yes the water did help with the cooling even if I just intended to wash the condenser a bit. The issue is why did the water not evaporate at some points in 5 minutes. It's almost like dropping water on a hot iron, it won't stay wet for too long. I do have a leak that I have neglected because it is a very slow leak, but that wont make my low side go up to 55psi when running at 87F or would it? I dunno really, but I am not sure it would. A mechanic told me the low side should be at around 40 and that the compressor is worn out.
    – charlie
    Dec 7, 2021 at 19:29
  • There! Another unprofessional mechanic looking to profit from anyone. If you like, refill your system (some require up to 1500 rpm while injecting refrigerant) and observe vent temps drop. If you feel vent temps drop it's because more refrigerant allows the compressor to work. If vent temps don't drop then there may be more diagnosing to narrow the problem down but my personal opinion is this isn't a compressor failure. On a normal operating ac system, low side pressures (some vehicles must idle higher when measuring pressures) vary from 30-35 psi, high side 150-250+psi
    – F Dryer
    Dec 7, 2021 at 19:45
  • Thank you so much for your time F Dryer. I will go out and get some gauges to measure both sides. I do get about 25-40 psi when revving the engine and the temp drops dramatically through the vents, but when I let go of the gas, it goes back up to 55psi with not quite as cold air coming out. Thanks again for your time, I won't make any more assumptions until I get a gauge that measures both side.
    – charlie
    Dec 7, 2021 at 20:52

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