Guys,

I've exhausted practically all solutions:

I've had the evaporator coil, receiver dryer and expansion valve replaced in my AC system. All lines flushed and evacuated. Refrigerant recharged and compressor oil topped off. There are no connection or relay related issues to report

It gets really chilly in the cabin as evening approaches. And at night, I'm practically in a mobile refrigerator, getting nicely frosted. So much so, that at times I feel the need to switch off the AC for a while.

During the day however, especially when my car's been parked for a while in the sun, the cooling's nowhere as good as it is when driving around after sundown. So now it comes down to the compressor; is it getting hot during the day, and keeps tripping to keep from overheating? Does my compressor need replacement? Also when the AC cycles back on, I hear this hissing sound coming out the vents. This same sound goes completely mute when I compress the clutch to shift gears.

I just can't quite put my finger on it. Why does the compressor perform somewhat poorly during the daytime, compared to night, when it's almost freezing inside? There are no leaks in my system as such, and refrigerant level is where it should be.

Please help, rather frustrated at the moment.

 

Make sure it's not overfilled. When it's hot out, the refrigerant expands, when it cools in the evening, it'll work.

 

Roger that! Has been checked up at three different AC shops. Refrigerant is neither overfilled or underfilled. Pressure is right where it should be.

Tell me this - if the compressor's pumping out cold air through the L pressure line (it is fairly cold to the touch), why isn't the evap blowing chilled air inside the cabin and sucking away the heat/humidity during the day?

Checklist - condensor's good. Recvr. Dryer and Expan. Valve replaced (not sure if there was any need to get these two replaced, probably got played). Pressures are good, compressor's functioning and cycling on/off exactly as it should. No leaks.

I've only noticed this mediocre cooling performance during the day issue after replacing the evap coil. It's not a genuine one, it's a cheap Chinese/Korean knock off.

Now, as far as not installing genuine evap coils is concerned, how much of a performance difference should one expect? Say a $60 knock off vs a branded genuine part recommended by Honda that's between $260 and 320$ (not including labor). Is it practically like night and day? Does the cheap knock off part explain why the cooling efficiency goes down by almost 40% during the day. I mean I don't sweat, but my body or the seats never really feel cool, like they used to. Neither do you get that sweet chilly atmosphere that makes you want to take a nap in your car!

Everywhere I go, these AC techs are giving me mixed opinions - you need to drive the car longer and at higher speeds; you need to replace both the compressor and condensor; you need to replace this or that, get this or that checked up. It's really getting on my nerves and I need somebody's honest opinion. Two AC shops recommended installing a better quality evap coil saying, it'll allow the car to get cooler faster, during the day.

So I've narrowed it down to the evap coil at the moment. Because my AC was performing like a champ during the day, before I had to have the stupid evap coil replaced (had a large leak in it).

A cheap quality one would explain why it's not getting cold quickly enough during the day, or sucking heat/humidity fast enough from the cabin. 2 to 4 mins is OK. But after more than 10 mins of driving, the cabin still just feels a bit cool, not cold. (Think 25 or 26 Deg C air coming from a split AC, as opposed to 15 Deg C or lower, which is how my car AC performs at night).

Please post your thoughts or recommendations. I'm nearly at my wits end!

 

Please take a look at these pics.

Thinking of installing this Thai manufactured coil. It's $120 compared to the $60 one I have installed at the moment.

 

Check that the hot water valve (on the engine side of the firewall) is closing when you put the dial on full cold. The heater hoses at the heater core should not get hot. These systems work by making the heater and A/C fight against each other when the driver sets some temperature other than full cold. If it starts doing that when it shouldn't, you don't get full cold.

But yeah, the conclusion that I had many threads ago was that your $60 evaporator isn't doing the job. It's also possible that some of the foam insulators on the sides are missing which allows hot outside air to pass around the evaporator and of course not get cooled.

 

I always keep the dial on full cold, never felt the need to change that. But it's a good suggestion, I'll experiment with that too.

About the insulators, are you saying the ones around the evap. coil being missing, or where the evap. coil goes into the dash, that area?

Pretty much everything so far has boiled down to the $60 evap coil. When the fins and tubes are not the right capacity, of course the air is not going to get cooled enough, neither will it do an efficient job of sucking heat and humidity quickly from the cabin. Also explains why it doesn't have to work as hard at night, though I've to wait at least 3 to 4 mins until the air is ice cold. A friend O' mine from Texas said the same. He says I need to have the OEM part installed. That's out of my range, unfortunately.

Can you please take a look at those shots of the Thai evap. core? Does it look legit to you, and that it would do the job in an 05' Civic, 4 door?

I really appreciate the FB I've gotten from you so far, thanks very much!

Happy motoring!

 

Mk378, here's the latest:

Check up at a 2s dealership revealed - H pressure line was quite hot, L pressure line indicated about 40 psi. Center vent temp registered at 55*F.
He then proceeded to splash the condensor with some cool water, and the H pressure line instantly started to get less hot, more mild warm to the touch. At this point, pressure dropped in the L line to about 30 psi, and then 25. He applied throttle to about 2000 - 3000 rpms, pressure went below 20 psi, almost touched 15. He says there's a choke in the system somewhere. And I might want to have the condensor replaced.

That, and get a proper OEM evaporator, as the fins are placed farther apart for proper heat disappation, as well as the tubes being designed to circulate cold air according to manufacturer specs. He said I might want to replace the receiver dryer and TXV with a manufacturer one as well, although these two parts are exclusively replaced with a brand new compressor.

Damn these expenses!