see if you have the same relay in your fuse box that goes to something thats not that important. like power windows as a example. temporarily swap it.
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Good idea, unfortunately the three fan relays don’t fit anywhere else and all three are the same size (of course). Is it safe/wise to remove them while the engine is running? I could randomly switch them around, but I’d have to drive around for a while to see what’s going on with the AC.
Then you are in over your head and need to take this to a mechanic that specializes in A/C.
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The fans will switch to high speed when the coolant temperature is 205 F or higher. I see no reference for an A/C pressure value to switch to high speed.
Relay # 3 is for low speed. Relays 1 and 2 are switched on for high speed. If there is a problem with relay 1 or 2, one or both fans would be inoperative.
So, I had the compressor replaced recently. Someone told me if the compressor fails, it sends junk into the condenser and clogs it up. I don’t think my compressor failed while running, though. It worked all last Summer, then I had the engine rebuilt over the winter. When I tried to charge the AC, the compressor would not compress anything. The car idled up when it built up pressure, but the compressor never worked. It also has a control valve and shuts off when there’s too much/little pressure. If the condenser was clogged, it would explain my symptoms, but my mechanic mentioned “cleaning” everything when he replaced the compressor. What do you guys think?
Well, turns out my belt is slipping. Ugh, if that’s all it was, I’ll be happy and angry lol. It was making a hissing noise instead of a squeal, so I didn’t notice it.
Here are my pressure numbers from this morning:
80 degrees outside, doors/windows open, max recirculate, fan medium high:
Static: low side-64, high side-122
Idle: Low-27 to 34, high-170 to 190
1800 RPM: Low-22 to 25, high-200 to 210
Vent temperature at idle: 51 degrees
Vent temperature at 1800 RPM: 46 degrees
You must have checked the static pressure before the system equalized. Both low and high side pressures should be the same. If one carried those numbers on out the static pressure could in theory could be roughly 90ish PSI. Too low IMO.
Doesn’t seem like much of a temperature drop at the vents for an 80 degree day. Temps of 46 to 51 would have you glued to the seats here in OK.
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Yes, I just arbitrarily listed the static pressure-it was taken shortly after the car was shut off.
I did lose a small amount of refrigerant from using the gauge, but I was told it should still be within range and not to worry about it. The AC is still fine, no better or worse.
And yes, the temp at idle is my problem. Later that day on the interstate it was 85 and sunny, my center vent was at 38 degrees (recirculate, medium high fan).
About all I can suggest is to check the static pressure after the engine and A/C has been off for a while. I am not trying to be combative so please do not take it that way.
I’m just saying that with every A/C I’ve worked with (including complete A/C system installs) the normal static pressures have been right at 120; both low and high side.
Even the low/high pressures you show at idle and elevated RPMs are not quite right. They should be higher than shown.
Again, and this is just my personal opinion, I think the system is undercharged and as I mentioned earlier I always charge by pressures; not the amount. Just some advice which you may or may not choose to use. Hope it helps.
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Hey, it’s all good. I appreciate your input. I’m sure the system was a tad low from recently hooking up two sets of gauges. One set was defective and I was left with a high-side hose full of refrigerant.
Here’s the reference for static pressure I found online:
Ambient/ Static
70 71 (psi)
75 78
80 86
85 95
90 104
95 114
If I took the median between high and low, it would be 93 psi on a warm engine (ambient for the system would’ve been higher than outside temp) before the pressures equalized, so yeah a little low.
I added another oz of refrigerant and a splash of oil and worked fine all day, but still crept up at stop lights. I don’t like guessing like that, but there’s a 2oz margin for the fill range and it will shut off if overcharged even slightly.
I’ll have to see how it does when it gets hot(er) outside. Yesterday it was only 85.
Those online stats don’t mean a lot to me because the simple fact is that both low and high side should be the same on a fully stabilized system. I have no idea why someone would use figures like 90 vs 104 when that is not a stabilized system. Both sides should be dead on exact with each other.
Connecting and disconnecting the gauges will cause a tiny bit of refrigerant loss but that should not be enough to fret over.
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Agreed. Also, the static reading before the system equalized is probably meaningless.The engine was still warm and had only been off for ~5 minutes.