I have a 2001 Honda Civic DX that is experiencing climate control airflow problems.

Air does fine when first started but within 15 minutes of driving the flow of air coming out of the vents starts to fade. Quickly.

One thing that helped was to take it out of re-circulation mode. It seems this allowed the air to at least blow a little rather than a complete loss, however it still reduces to almost nothing after time.

The temperatures are good. With AC on the minute stream of air blowing through vents is ice cold. With heat on the air is still warm.

After some research I'm leaning toward the evaporator freezing up, which would make even more sense now because when I first bought the car in the summer it would drain what seems like an excessive amount of water from the evaporator drain line.

Anyway. Just wanting some thoughts or tips or anyone with experience with something like this to lend any comments.

I'm thinking it's an evaporator temperature sensor. How hard is that to replace and do you have to take the dash out to get to it?

Thank you.

So to follow up to the first post. Went out and started the engine up. Turned climate control to full heat. Within 5 minutes saw the line going to the evaporator frosting up heavily. Turned climate control off, appears to be same condition. I can see the belt moving on the compressor but cant tell if the pulley is spinning. Will have to wait to get home from work to investigate further. I would assume it is if it's pumping refrigerant through the AC lines. Any thoughts?

 

This thread may help you: https://honda-tech.com/forums/honda-...istor-2041582/

 

Replaced that already haha. When I first got the car there was no air at all. This fixed that but now it just fades out.

 

So another update. Took the car out just now. Airflow stayed good for about a 10 minute drive. Got back checked the line that was frosting earlier, not as frosty but still cold to the touch. Might have been a little more humid this morning or something. Also ran the diagostic for the AC system. No codes. Sorry for all of the posts, just trying to get as much info as possible.

 

frosting lines, or frozen evaporator=low refrigerant charge. Have you line pressures checked.

 

Would anyone have a solid "limit" for what a bad gauge reading would be? I see in the service manual the system holds 500-550g of refrigerant. I also see magic numbers of 196Kpa and 3,140Kpa. I picked up some UV dye refrigerant, but I'd like to know the range of pressure before dumping in more refrigerant. I could pull a vacuum but I know for a fact there's refrigerant in the system. Like I said, the air is cold when it needs to be, just loses airflow as you drive on any setting. Anybody have a way or method of recovering refrigerant without a recovery machine? They are quite expensive for a DIY'er. Thanks again.

 

Spotted a general limit of high side pressure of 20psi and low side pressure of 40psi while surfing the web. This can't be a great set of number to go by considering temperature and elevation play a role in pressure. Again, sorry for all the posts. Just trying to talk through this and get some tips for troubleshooting and such.

 

Huh? Every vehicle is different. Most evac, and recharge by weight. Generally low side is about 35psi and high is about 250psi. Some go to 450psi. Like i say. Every car is different. Hard to find pressures sometimes.

 

So I hooked up the gauges and got 32psi on the low side, 115psi on the high side. I noticed the compressor is constantly engaged and spinning. For a quick cheat I pulled the relay so I have heat (it's getting colder), and it works great. Checked the relay with multimeter, checked good. I noticed that I managed to get a little bit of dye running through the system (this is a whole other story about faulty equipment from a large auto part retailer). I didn't see where there were any leaks on the AC system lines right off, but there was a liquid lighting up on the transmission that made itself more apparent with the UV light. I looked above it where the AC lines run and didn't see any signs of dye, though. Also it was holding pressure beautifully at 32 and 115. I'm kind of down to evaporator temperature senor, bad compressor/clutch, or maybe my refrigerant pressures are high or low, but from all the number's I've seen in the service manual I think they are good.

I'm also wondering if maybe the guy who had the car before me may have attempted an AC system fix and opened the system and didn't evacuate the system properly. Would explain why it's not showing signs of a leak, but still has moisture in the system.

Thoughts?

 

your expansion valve is likely bad, when it stops blowing, without turning off the ac, open the hood and see if one of the two lines going into cabin is freezing over

 

Indeed it is. The low pressure line is freezing over rather bad and rather quickly.

 

To replace an expansion valve you have to pull a lot of the dash out and evaporator as well? Any brazing involved?

 

it depends, not usually though

 

https://www.rockauto.com/en/catalog/...r+manual,10335

get the Bishko on cd rom and plug 6578467445519067 into "howd you hear about us'

 

115 is to low.

 

Ordered the CD Rom. Went ahead and got an expansion valve and started tearing into the system. All bolts were so corroded that I wrung two off. Went ahead and just ordered new lines since they were in rough shape as well. The low pressure line was actually cross threaded onto the suction line going into the compressor. It was actually low on refrigerant. I'm gonna replace most of the system, including the filter drier and evaporator, pull a vacuum and see what happens. The expansion valve didn't look in too bad of shape but it appeared to have a leak around where it mates to both the low and high pressure lines.

The guy I took it to to recover the refrigerant said to put a few ounces of refrigerant oil in both the filter drier and the evaporator itself. This sound correct?

Thanks for all input.

 

in the ac section it tells you how much oil to add when replacing each component

 

Perfect. Yeah I'm stoked for the manuals. It was very reasonably priced also! Thanks a lot!