Civic05'

Hi.

A little history on my Civic's AC repair/maintainence:

A little over 2 years ago, I had the cooling coil, I believe it's called an evaporater here, welded. Since there was leakage. It worked great for a while. Then about 6 months down the road, I started to hear clicking sounds coming from the compressor, even though it would remain engaged and the cooling was great. Coupled with this, I could hear a partial whinning, partial howling sound coming from the compressor with higher revs.

Eventually the compressor failed to engage as the clutch magnet wasn't working. So about 2 years later, I had the clutch magnet replaced, along with the bearing, as well as the compressor seal. Worked great for about 2 months, then the cooling coil/evaporator gave out. Had it inspected, and was told it needs to be replaced as the leakage couldn't be sealed with welding a second time.

So now that everything is A-OK, I feel my AC's not cooling as much as it used to to. I live in Karachi, and it gets very hot during this time of year - 40 deg C or more. The AC technician did a vacuum and pressure test seperately on the condenser, cooling coil and compressor, and there were no leaks. It was cooling great as I was pulling out of the repair shop. But the next day, especially with the car parked in the simmering heat for 30 mins or more.. driving it around for 10 mins, I didn't feel the same amount of cooling was present. At night it works fine, though not as cold as I would expect.

The AC tech said something that struck me as a bit odd as I was leaving: he said it takes a day or two for the compressor to regain pressure completely, and it's going to work even more efficiently after a day.

There are a lot of question marks hoverying around in my mind ATM. I'm going to take it back to him in a day or two, but I also want to do my homework. Apologize for the lengthy post.

What do you guys recommend? Anything wrong with my AC parts at all?

Civic05'

Another observation:

The compressor just turn on and off intermittently every few seconds. Doesn't stay on, which explains why the cooling isn't a 100%. Also, when I start the car up for the first time in the morning, and turn on the AC, the condensor fans start spinning. Isn't that odd? Aren't the fans supposed to turn on only when the condensor's hot? When I switch the AC compressor off, the fans go off too.

Hey help me out here fellas! I'm visiting the workshop in a day or two and I absolutely need to be prepared before I go!

Civic05'

Hey, I drive an 05' Honda Civic.

I recently had the evaporator coil replaced. And since then the AC hasn't been cooling at maximum efficiency. The compressor goes on/off intermittently for no reason. I've had it checked for leaks, there are none. Also compressor gas is full, and there are no leaks in this regard.

This happens whether it's day or night, whether the blower fan speed is low or high.

Ideas?

EM2abe

check fuses and relays. check all connections.

Civic05'

Great. I'll ask the tech to do that when I take her for a check up.

Will get back to you on that! Thanks!

Civic05'

Update:

So I got her all checked up at a 3s dealership. No connection or wiring issues, none with relays or fuses either. They said it's most likely the expansion valve and receiver/dryer that needs to be replaced. Which may be causing the AC to not cool at a 100%. Or I could just live with it and not mind the slightly lower cooling efficiency. Both parts will set me back around $100.

A little history:

A few months ago, I had the AC compressor clutch replaced. Along with the compressor bearing and seal. Worked fantastic for 2 months, nice and chilly. Then a large leak in the evaporator coil led to a leak overnight. (I had had the evaporator coil welded almost 2 years ago to get rid of a leak). Even then the AC tech had mentioned keeping an evaporator coil replacement in mind.

So I had the evaporator coil replaced recently, and now the cooling doesn't feel a 100%. Honda says, usually the expansion valve and R/D are both replaced when the evaporator coil goes.

So now I'm stuck in a bit of a rut - do I REALLY need to have the expansion valve and R/D replaced, or is it fine to just live with 20% less cooling? By not replacing these 2 components, am I harming my AC system in any way?

Also, how could the expansion valve and R/D be faulty ONLY after having the evaporator coil replaced? I had the system recharged on the previous coil, and it worked at full capacity. Even though it lost charge after just two days.

I shall eagerly await your feedback! I'd also welcome other members and experts to share their thoughts and comments. Knowledge is like a double chocolate cake that just has to get passed around!

EM2abe

just spend the $100 on the parts and be done with it.

Civic05'

That was my initial thought.

But I'm hesitant as the workshops around here have a knack of breaking things that don't need fixing! So you really gotta live by "if it ain't broke, don't fix it" around these parts!

I may get it done somewhere down the line. Cooling's OK, but not as good as it used to be. I guess I can live with that for now.

Bottom line: am I harming the AC system by not having these parts replaced? I've also noticed when the blower fan is on a much lower setting, that there's a hissing sound that comes from the AC, when the compressor turns back on. No clicking sound from the compressor, just this wierd hissing sound, during which the cooling goes up a little. Particularly happens while the engine revs are going up.

^^ This wouldn't have anything to do with the EV and R/D, would it?

EM2abe

personally i wouldnt really be able to tell you. im not pro on A/C...

Civic05'

Alrighty!

I thank you for the input EM2abe!

Can anybody else please offer their thoughts and/or opinions on the matter?

I'd super-appreciate that!

Civic05'

Can somebody please offer advice on my issue?

Thanks.

toyomatt84

iTrader: (1)

You're not harming the A/C system by not having run at 100% efficiency. Even if you had lost all Freon in the system, you'd be unlikely to cause damage to the system unless some foreign debris got into the lines somehow (you'd have to have a rather large hole in the system somewhere).

Civic05'

I've found the culprit - it's the evaporator core. It's a cheap chinese knock off. The guy was fairly honest and upfront, where I had her checked up recently. There is absolutely nothing wrong with the AC system. The evaporator core is not efficient enough. That's all. Nothing I can't live with. So all good!

Civic05'

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.

Civic05'

Hi,

I'm not sure if I'm getting any responses any time soon, but I'll post anyway.

My question is regarding cheap knock off parts.

Say, a Chinese made evaporator coil that's available for $60 vs a Thai manufactured one that goes for $120 (according to AC repair shops here, apparently it's considered genuine) vs the one you get at the dealership - $320.....

How much of a performance difference would one expect between the three? I'm currently on a Chinese one, as the AC repair tech told me it performs as well as the genuine one. Well, it's not doing the job it's supposed to, and cooling is nowhere as good during the daytime, like it used to, when it had the factory stock part installed.

By getting the Thai manufactured one, how much of a performance improvement can I expect? The Honda one is not even on my list, they're charging too much for it.

My AC system checks out fine; high and low pressures normal, compressor good to go, condenser's fine. Had the receiver dryer and expansion valve changed as well. But that has improved cooling performance only after late afternoon, not during the day, when it's been parked in the sun for more than an hour. I also had it evacuated and flushed completely before adding comp. oil and refrigerant.

Please somebody, help me with this dilemma. Summers are practically at their peak and I can't be driving around for 15 mins, just waiting for the AC to start cooling properly during the day.

Does the Chinese evaporator core need to go then?

Civic05'

^^ Please help and/or respond someone!

toyomatt84

iTrader: (1)

Little to no change what so ever. The only real differences will be in the part's longevity. It may wear out quicker then the factory component. But, that'd be down to build quality. Other then that, there really wouldn't be much difference at all.

I think you're making a bit of a mountain out of a mole hill here.

Civic05'

Mountain out of a mole hill eh?

Well, how do you explain less than exciting cooling during the day, and freezing cabin temperature's at night? You're probably aware of the repair and maintainence history of my AC.

It's gotta be the evaporator core; it's unable to suck all that heat and humidity out of the cabin quickly enough. Under the hood inspection: low pressure line was cold to the touch. High pressure line wasn't so hot. Just between warm and hot. This is on an overcast day, with rain forcasts, temp - 30 Deg C. You're telling me, it's not cooling properly during the day in this weather, and the evap coil is working properly?

Well, I'll have to do some more research on this. But all the other components check out fine. Even had the Expan. Valve and Recvr. Dryer replaced. No difference in daytime cooling performance. I increase the blower speed, and the cooling seems to suffer a notch a two.

All signs point to a cheap evap coil. But I'm still very much interested in your insights. Like I said all other components check out fine, including the operation of the compressor and gas refrigerant levels.

Civic05'

Still researching forums to dig up any info I can, regarding my issue. But this is the coil I'm planning to install, provided it checks out fine. Please take a look and comment.

Thanks.

JJ291

Civic 05. I'm not an HVAC tech but I have torn deep into my home AC and have a lot of specialty tools - it's not too scary once you get into it. I haven't done much with a car either but the principles of HVAC in a car are the same. Just a couple of thoughts - you might hit up Harbor Freight or Autozone and get an AC manifold with connections for a vehicle. If you have a honda service manual they have charts in the HVAC section that will guide you how to check the system performance. You will also need a cheap thermometer to stick in your vent. I would challenge your HVAC guy to show you how he is checking the system. My guess is that you can find this chart somewhere on the forum already. Another thought is stop chasing the evaporator. The fan recirculating air inside your car over the evaporator could be fine. The evaporator could be fine. But the condenser could be plugged from corrosion or not functioning correctly. As the cool air at night improves the condenser performance it pushes the AC into the correct operating range. But during the hot day the condenser cannot remove heat as effectively and thus leads to poor performance. Not an expert but if it was my car I would be checking:

- performance against the charts in the service manual
- condenser condition

Just my two cents. If you don't understand the way an AC works I'm happy to give you a description also (not trying to offend if you do, just an offer).

Civic05'

I have gotten my AC checked up at 4 places, including a 3s dealership. They say the H and L pressures register good, according to Honda AC operating specs. The condensor is not clogged. I had the entire system flushed and evacuated when I ended up replaced the Recvr. Dryer and Expan. Valve too. The compressor's working good, pumping out cold air. The L pressure line is cold to the touch. But apparently, the evap. is not performing like it should. I've gotten all components checked up, they're good. No faulty wiring or relays.

It's a cheap $60 evap. coil you see. The OEM part cost anywhere between $260 and $320. More than likely a performance hit is what I'm experiencing. The one I have probably doesn't have the right number of fins and tubes to cool the cabin effectively, whilst sucking away heat and humidity at a good pace. Either that, or cheap build quality.

And yes, I am fully aware of how ACs work. Particularly car ACs. There's a thread here on Honda-tech that also does a fantastic job of explaining the inner workings, and a list of diagnostic techniques to determine problems.

Everything is working good from the engine bay, right up to the expan. valve. But the car doesn't get cool enough, fast enough. I thank you for your FB, but my money's on the cheap evap. coil. It's not up to the manufacturer specs.

Say, you blow out a tyre on a truck that weighs over 2 tonnes. You can't just fit a golf cart tyre and expect it to run efficiently, and not blow out again.

Could you take a look at the evap. coil shots I posted, and tell me if it looks legit? Would help me in deciding which one to get.

JJ291

No worries. To answer your specific question about the quality of the evaporator to me there are three main components: metallurgy, heat transfer area, and flowpath (configuration). Heat transfer is controlled by the equation Q = U x A x LMTD, where U is the overall heat transfer coefficient, A is the heat transfer area, and LMTD is log mean temperature difference. U can be affected by the metallurgy and the evaporator design. I'm guessing the metallurgy will be close and do not think that would swing things too much. The heat transfer area would be a function of the tube diameter, the fins per inch, and the size of the fins (given the system performance, velocity, etc are unchanged). I would think all this could be verified simply by inspection for the most part. The log mean temperature difference is more a function of the design and that may be where you're getting bit if you don't have the right cabin airflow or freon temperature, velocity, and vapor/liquid percentage. Maybe not what you're looking for in this discussion but to me those are the important things from a design standpoint.

In terms of quality, it says "leak tested". Who knows what that means but that is the only place you might be suspicious - quality of construction, did they hydrotest the unit, etc. Not sure I can help you there, you may have to take your chances - it does state Civic/CRV on the unit so I gotta figure that is at least a good sign.

I did a quick Google search on this topic (as I'm sure you have so don't get insulted) and it looks like for the most part the two main causes are overfill of Freon and poor condenser performance, outside of the obvious which is the compressor not engaging which seems to be more of a symptom of overfill than a cause of poor performance. I'm attaching a few links worth checking out:

http://forums.nicoclub.com/ac-works-...s-t350567.html

https://honda-tech.com/forums/tech-misc-15/c-barely-works-daytime-but-very-well-night-2776241/

One good thought in the articles is to run water over the condenser and see what happens. In terms of the condenser btw note that in one article it was the outside of the condenser that was the problem, not the flush.

You gotta go after what you think it is, brother, but I guess the part I struggle with in saying it is the evaporator is let's assume for a moment that the cabin fan is working just fine day or night. The heat transfer into the car is presumably less at night than during the day so it may be that the air conditions across the evaporator are slightly different but once the car is cooling it should be very close to the same. If it was the evaporator I would expect the crummy performance to exist day or night. I believe the only difference day to night in terms of heat load on the system is how often it must run and the fan speed. However, the heat is rejected through the condenser and that depends on the ambient air temperature. However, as noted in the articles compressor performance is also impacted by this if it is not filled correctly.

Well, lots of words, but probably not much help. For that much savings I'd go with the cheaper one but that's just me.

JJ291

Hey Civic 05, had another thought on a test you could run. This all assumes that the Freon charge is OK, which it sounds like it probably is.

Wait til heat of the day, put your car in the shade, fan on recirc, and run a hose over the top, doors, panel, etc while it's in idle. Goal is to cut the heat load in the interior but keep daytime temperature air on the condenser. If the condenser is working and the evaporator is the problem, the reduced heat load may have it cool in no time because the evaporator can transfer heat to the Freon with reduced heat load (simulate night time conditions). Then, put it in the sun and get it nice and toasty, run a hose over the condenser to simulate night time air with daytime heat load. If it cools way down then you know the condenser is the problem and the evaporator is fine. Just a thought.

Civic05'

Hey, thanks for the feedback. I found it incredibly helpful!

The links you provided offered some useful insights into this kind of issue. My freon levels may be overcharged. But I know for sure the compressor's working good. It could be the condensor that's not working a 100%.

The L side pressure indicates 40 psi at around noon, which I guess is high. The AC tech at a 2s dealership was inspecting my AC and like you said, he just happenned to splash the condensor with some cool water. Sure enough, the pressure dropped to about 20 psi, and the cabin vent temp instantly went down by at least 3 to 4 degs. Subsequently, the H pressure line felt less hot to the touch at this point. He applied throttle to about 2000 rpms, and the L line pressure went to 15 psi or below I think. He said this meant the system is clogged somewhere. As I was driving home, I immediately noticed better cabin cooling.

In the end, he recommended getting an OEM evaporator along with the manufacturer recommended receiver dryer.

The hose test you've recommended seems like the ticket. But the problem with my home is that the water in the lines gets rather hot during the day. Not heater or geyser hot, but hot enough to make you not want to splash it on your face! I doubt if the hose test will yield accurate results in my case, but as you and other members pointed out (the link you provided), the condensor working better after being splashed with water, is a cause for concern. I'm taking her to an AC shop day after tomorrow, owned by a tech who used to work at a 3s dealership. Honda actually recommended him. He said to me, all he'll do is take out the evap. I have, vacuum the system, install the Thai manufactured one (shots posted), recharge freon and comp. oil. He'll let me drive around for 2 days, and if I don't see a difference, he'll take it back, and install my previous evap. coil back! Not a bad deal if you ask me, but if it doesn't do the job, I'll end up paying for both the freon recharge + labor jobs! Worth a shot I think.

In the meantime, I'm contemplating how I can fix the condensor issue, if it is indeed a serious one. Certainly can't afford a new conden. ATM.

Does it make a difference in performance, if the receiver dryer and expan. valve are OEM? I had those two replaced as well (in a bid to rectify the issue, silly me), and they are aftermarket parts.

JJ291

Hey Civic 05. I'm going to change my tune based on what you reported in your last post. It sounds to me like your system is overcharged. I'm attaching 3 pages out of the manual for my 01 Civic that may help - I can't imagine much changed in 02-05 but it would probably be a good idea to check (maybe someone on here already has it posted). In any case, look at the troubleshooting page and it specifically states that if you have a high suction pressure on your compressor and you put water on the condenser and it drops, that it is overcharged. I would argue the same case would be present if the condenser was not working correctly. To my way of thinking, the difference in pressure across the compressor is a function of the specific gravity of the gas multiplied by the head. As the gas cools, the density increases, the compressor moves back on it's curve, the pressure difference across the compressor increases and the suction pressure decreases. This also provides a higher pressure drop across the expansion valve which suddenly starts doing it's job. I would argue that the case of a condenser working incorrectly due to plugging or fouling is the same and the water greatly increases the cooling across the condenser resulting in the same as described above. Meaning, whether the condenser is not working or the system is overcharged it will result in high pressures. In any case, hopefully that chart helps you figure out where it should operate before the tech pulls out the evaporator. Incidentally, I swapped my transmission last year and felt like I was spending so much money on it that I needed to protect it by replacing the radiator. I was able to find an OEM Denso radiator at Sparkplugs.com and I noticed they sold condensers. I would get the part # and search by that # instead of doing a general search. I got it for $60 and it was OEM (vs. 200+ from Honda). Well, hopefully you find your answer - it looks pretty dang hot in Karachi!