Air condtioning mystery

This summer, as the temperature goes up, the air conditioner in my 03 Honda Civic works less and less. Now, a sensible person would take it to a shop, but I just switched jobs and am moving so I don’t have that kind of bread.

Here’s all the anecdotes that I gathered from a recent trip from Minneapolis to Duluth, during which I got to quite literally stew on my observations.

On the way up it was 85 or so outside. The air would work briefly, but then start blowing muggy, roasty, ambient air. If I shut the AC and the fan down for a while (no consistent amount of time), then turn it back on, it might work again for a little bit. When it DID work, any adjustment to anything (fan speed, temperature dial, air recirculation), caused it to stop working. The longest amount of time it worked for was about 26 minutes. I got over the AC problem fast because Lake Superior is mother nature’s supreme air conditioner.

While we were in Duluth, I tried swapping in a new relay, because I had read that sometimes that was a reason for intermittent AC. The following day I drove another 40 miles north to Two Harbors and rejoiced! It worked! (The outside temperature was around 70)

A day later I was crushed, because as we drove south and the temperature rose, the AC got worse until about 90 outside when the windows were the only source of relief. It made no difference if it was highway speed, or bumper to bumper.

Back home in the driveway I’ve run the car and the compressor will run. The fans both spin, and the air blows cool. After driving around the neighborhood for 15minutes or so the AC worked feebly, but it still worked.

When it’s running strong, like right when I start driving after the car has been sitting, it blows ice cold.

Am I destined to switch to having my windows open? There is so much summer left… and more summers after that.

One possibility is that the evaporator is icing up blocking the flow of air through the evaporator coils. Turning off the air conditioner allows the ice to melt and then it will work again when switched back on. The usual cause is that the refrigerant level is too low and the system needs to be recharged.

It could be any of a variety of malfunctions of course, but it seems to me like you just have to have your AC serviced is all. If you can’t afford it, well, welcome to the club! So save up, and eventually you’ll have enough to get it properly serviced.

Here’s a link to a good 4-part tutorial on auto AC fyi.

I’m betting on an electrical issue, like a short in the compressor wiring harness that appears to act up randomly. If that’s the case, you’ll need a new compressor.

I’ll go with low refrigerant. You can buy those do it yourself cans at the parts store with a gauge and add it. Honda’s of this era do have compressor problems, at least on the CRV.

Some parts places lend out gauge sets that lets you measure the high and low port on your AC so you can see what your compressor is doing. Harbor Freight also has one on sale for $59 - sometimes even cheaper with a coupon:

I go with low refrigerant too.

@knfenimore, why would low refrigerant cause intermittent failure? Wouldn’t low refrigerant cause constant failure?

@RemcoW, suppose mikosity gets the gauge and finds she has low pressure on one of the ports. What then? Fixing it won’t be a DIY job, and any A/C technician who knows his stuff will insist on doing his own diagnostic work.

@mikosity, those cans of refrigerant you can buy at the store, especially the ones that come with a gauge, are a huge rip-off. If you have a leak, adding refrigerant won’t fix the leak. If you don’t have a leak, you won’t be able to add refrigerant, but just breaking the seal on the can of refrigerant means you can’t return it to the store, and they often come in packs of three. Even if you discover you have a leak, fixing air conditioning systems is not for the average do-it-yourself mechanic. Paying the money to have a certified air conditioner technician diagnose and fix what is wrong is the best path to a solution.

@whitey, yeah I hear ya. It isn’t for everyone. Hating to hire anyone to do anything for me, I did go that route, though. Bought a gauge set, found a leak, then bought a vacuum pump and did what had to be done.

I’m not sure of all the dynamics here, but if the system is just a little low on refrigerant, it seems to trick the expansion valve into staying open too much, causing the evaporator to get too cold. The warm, moist air going through the evaporator then condenses and instead of gripping off, it freezes to the evaporator.

Honda’s also sometimes have a problem with the hot water control valve not closing completely when you turn the dial all the way to the cold position. I have to manually close ours at the start of summer, but the OP’s description sounds more like low refrigerant to me. If low, it surely has a leak, BUT, the leak will be so small that it will likely not be detectable. It may be low because the AC wasn’t used at least 5 min per month, even in winter. Generally you should select the AC button when using full defrost in winter to keep the AC in good order.


This is somewhat off topic, but here goes . . .

Over the years, many (perhaps even most) of my colleagues haven’t been legally licensed to even do automotive AC work (that is, they don’t have their 609 certificate). I will say that it’s very easy to get. It’s quite possible many of them never even realized that you’re supposed to have this.

Then there is the other matter that some of them lack the fundamental understanding of how AC systems work.

To sum it up, there’s no guarantee that a certified and competent mechanic will work on your AC system if you bring the car to a shop.

Best bet in my opinion

609 certified
currently ASE certified in auto HVAC
experienced mechanic

This is NOT meant to imply that somebody without that stuff doesn’t know what they’re doing

You really need to have the gauges put on the car and find out what the pressures are. The car is a 2003 so it’s reasonable to expect some refrigerant loss.

The issuance of a license may or may not mean anything. The licensed HVAC guy who came out to my youngest son’s house a couple of years ago stated that 81 degree outlet air on a 100 degree day was normal (Not) and changed the filter. He put a square filter inside a much larger rectangular opening so not a lot of air was being filtered. Like that would have anything to do with it anyway.

The second licensed company he called out was even worse. This licensed HVAC guy stated that my son caused the problem by washing the outside condenser coil of dirt and grass clippings and that “washing a condenser always causes Freon loss”.

A field trip to the son’s house with a set of gauges quickly found a compressor on the way out.


That’s a good story, and it illustrates what I was saying.

Not all licensed guys know their stuff

I’m sure there are licensed technicians who don’t know their stuff. You could say the same thing about just about any license or certification. For example, I’m sure there are board certified surgeons who are so full of themselves that they make careless mistakes. I’m sure there are certified financial planners who are less competent than some uncertified financial planners. Nonetheless, I think going with a professional who has a certification improves your odds considerably, which is why I’d never let a doctor who is not a board certified surgeon operate on me. Some certifying bodies even have ethical and professional standards that give you an additional avenue to redress grievances. I doubt this is the case with automotive certifications, but you never know.