teamo

02 CRV EX. A/C has worked great since new. Never recharged or had to service it. A few days ago it was around 80 degrees F and it didn't feel quite as cold as it should. My wife came home today after driving it and said it was blowing hot. Put a thermometer in the vent and it was ambient temperature. Checked the low side with one of those on top of can gauges and with the car running and the a/c on max it immediately pegged the guage to highest reading which is about 90 psi. I thought the guage was possibly broken so I checked it on our other car. It worked fine. What causes an unusually high reading on the low side? I could see if it was serviced and someone accidentally put too much R-134 into the system but it has never been touched by anyone.

silvertaxasteg

Is the condensor fan coming on? Is it blowing colder when you're traveling, say, above 25 mph? What was the high side pressure?

teamo

The fan is coming on. I think it is a little cooler when driving but I'll have to check that. I don't have a high side gauge. I only have one of the low side can top gauges. I am going to pick up a full gauge set today. I still have to check if the compressor clutch is engaging. If the a/c light is on the climate control dial and the condenser fan is running does that mean that the fuse/relay checks out okay? I also read about testing for power on the low pressure switch if the clutch doesn't engage. Where is the switch located? I can trouble shoot with a meter if I can find it.

teamo

Really hard to see the compressor from the top of the engine bay. I had to remove the lower plastic under shielding to get to the compressor. I checked and the compressor was not running with the a/c on max. I followed the wire harness with my hand to see if it led me to the low pressure switch. Couldn't see too much from the small access space where I had removed the shielding. Must have touched a loose connection because I restarted the car and the compressor is now running. A/C is running cold now. I already returned the low pressure gauge that I had bought to the store. I had planned on buying the gauge set but the guy at the store said that the professional gauge set only connects to the large 30lb cans of R-134 and that a license is needed to buy those cans. Is there any kind of adapter that can convert the gauge set to hook up to the small cans?

silvertaxasteg

Was not aware that 30lb cans had different connections than the small 12 ouncers. Never saw anything like that when I worked a parts store counter. I would call bogus until further notice.

Anyway, go back and see if you can track down the bad connection, as it will likely do it again in the future. Good to hear it's working for now.

OneBadTurboCRV

Yes, the connection is different from 12 oz cans to 30 lbs cylinders. Yes, there are adapters readily available. You need something to puncture the can and the cylinder has a valve. I have never been asked for an A/C license number when buying 30 lb cylinders. Maybe try a different parts store.

silvertaxasteg

Of course you have to get a tap for the cans... But aren't the threads on both the can tap and cylinder valve the same?

Good chart, by the way.

Not aware of any Texas laws either. It's not federally required to have a license for R-134a. Maybe it's a Massachusetts thing?

OneBadTurboCRV

Well of course the adapter has the same connection after the conversion haha... that's the whole point of having an adapter. If you read what you wrote you specifically said can vs tank threads. Not tank vs adapter threads. Also, if you read the post referenced above that it makes the picture even more clear of why I cam to my summation.

This is exactly what I pulled right off the A/C rack at my local AAP:

http://shop.advanceautoparts.com/p/i...-134/9016279-P

If the seal ever goes bad they are cheap enough to be disposable and thrown away. Although I would be willing to bet I have over 100 cans on mine without failure (helping people out that wanted a "specific refrigerate").

silvertaxasteg

I was referencing teamo's quote here:

I was referring to the connection from hose to can/cylinder - in the context of teamo's quote, I thought it was clear. Regardless of how the can or cylinder is tapped, it has the same thread for a manifold set, correct? OP says the counterman claims the hose set is only for 30 lb cylinders. I'm saying I don't think that's right, as the connection on the hose side should be the same for both cylinder or can.

OneBadTurboCRV

The threads from the hose are the same as the can but not the same as a cylinder. The cylinder threads are smaller and requires an adapter (the hose collar slips right over the threads). The issue with the can is it needs to be punctured and the threads are so short that you can't seal it with the hose o-ring due to lack of a tit. I took the time to take a picture of all this.

For cans you need the adapter with a puncture valve. For the cylinder you need an adapter for the smaller threads to the larger hose threads. All the thread standards escape me but they are all easily looked up on the Internet.

***Obviously it was hard to get all the pieces on the same plane so the size difference may not be as noticeable. Sorry, but I wasn't going to spend all day proving what I already know... ***

silvertaxasteg

Thanks for the picture - that is great to show the confusion.

Again, it doesn't matter how the can is tapped. That's not what I'm debating. When I said there were no differences, I was specifically referring to how it screws to the yellow hose.

For automotive R134a use the can taps and cylinders both use 1/2" ACME threads - so the yellow hose needs no adapter. Residential R134a cylinders use 1/4" SAE (also called 'flare'), so if you're using a residential cylinder with an automotive hose, you'll need an adapter.

I forgot that residential cylinders have a different thread, but that is immaterial to the topic, and didn't enter my mind until now. For cylinders and can taps, both rated for automotive use, no adapters are required to use with the yellow hose - all are 1/2" ACME.

In the end, the counterman is wrong - with or without an adapter, the 'professional' hose set can be used for cans and cylinders - residential or automotive.

Where did you purchase that cylinder?

OneBadTurboCRV

Must have been a mix up because I got this cylinder from Advance Auto Parts haha. Maybe someone pulled a fast one and returned it or something after it "fell off the back of a truck" - who knows. In the end we were both right haha... Thanks for clearing that all up.

I don't do it professionally anyways and have had this same cylinder for almost 5 years now. Most people want those stupid cans. They get sold on what the label says, though all I do is try and help some friends and family.

silvertaxasteg

It seems you got your money's worth out of it. Maybe you ought to look into a scale, too.

Interesting reading on using the cans.

When I replaced an A/C compressor, condensor, and accumulator for an older Grand Am, that's all I used. As far as I can recall, there were no issues with cooling after that. So it goes.

One thing to remember, since we're talking about vapors, we always talk in terms of weight ounces, not volume ounces.

Teamo, I encourage you to get a manifold set and a probe thermometer; valuable tools when working with A/C systems.

teamo

It's been a few weeks and I am still running into trouble with this a/c. I bought a gauge set so I can check the high and the low side. Seems that the pressures are right. Today the temp outside is 90F and the low side was reading about 50 (with the compressor cycling on). The high side was around 230. From the charts that I have read, and they all seem to be slightly different, that is in the right range for the outside temp. I have checked it on cooler days and it is reading about the mid 30's on the low side when it has been 75F ambient temp. The a/c seems to work fine on some days and other days it is cold but gets warm when I slow down or stop at a traffic light or am sitting in stop and go traffic. From the chart that was posted by onebadturbocrv I think there is a possibility that there is air/moisture in the system. If I evac the system and vacuum it out does it require replacing all of the oil in the system too? Is this a receiver/dryer system? I read in an a/c manual that whenever there is moisture suspected in the system that the receiver should be replaced after evacuating the refrigerant.

dogbiscuit

it sounds like moisture to me but im no expert.

Vacuum out the system and verify it holds vacuum. put a pump on it for ~30 minutes and then turn it off. see if it holds vacuum for ~30 minutes. if it doesn't you may have a leak (but it could be your shitty guage set from harbor freight not tightened correctly, from experience). then you'll need to try and locate the leak with dye and just enough refrigerant to make the compressor to work. you'll need the UV light and glasses to locate the leak.

when the leak is found replace that part in the system, the service manual will have the appropriate amount of oil to that part i know on the 97-01 crv takes 10ml in any line/dryer 40 in the evaporator and 20-30 in condenser. I only know this because i recently replaced evaporator/condenser/receiver/and both lines on my system.

Also autoparts stores r134 costs a whole hell of a lot and has stuff like snake oil whatever in it that doesn't change it. r134a was made by dupont it's all the same nothing is going to get you colder. Save money and buy the generic $10 12 oz cans of r134 from walmart.

it's imperative you know how much r134 your system should have theres a threshold of ~2 ounces that you must stay in or it'll not work properly. too much r134 and you get hot ac just like too little.



there's a lot of mixed information out there on this stuff. vacuuming the system won't take much oil out with it. machines at shops will add some with it and they typically charge on the high side. those machines cost around $8000 and it'll cost you 70-100 to have it recharged there. if you're concerned about it being charged right I'd say vacuum it yourself prove to yourself there isn't a leak and then replace the receiver and vacuum again to get any moisture. you can add the proper amount of oil directly to the replaced part.

Pag-46 oil is what you will need its basically the same as the stuff listen in the service manual that you can't find in USA.

check youtube for eric the car guys videos on AC systems. this got me from having no AC and leaks everywhere to a fully functioning system.

marshun

ac has never been worked on before. you can vac it, wait till theres a little amount of pressure, replace receiver drier (if theres moisture then that things fucked anyway). vac again till about -29. close valves and see if it holds, if it does then charge away. don't overcharge.

but from what I've read in your posts. it sounds like your compressoris dying. sucks I know. one of my cars just had it die too. had to replace everything. when a compressor dies it likes to **** metal shavings everywhere. so evaporator, receiver dryer, expansion valve, condenser all have to get replaced, flush the lines while theyre all disconnected. new orings on everything. fill each component with 2oz of pag oil. vac and charge. I hate doing these. haha gotta be done though.

silvertaxasteg

Since the system has never been opened, and the at-rest system pressure is above ambient, I'm hesitant to believe moisture is in the system. However, the only sure way would be to evacuate the system and pull another vacuum.

Is there an A/C thermostat that you can test? It tells the compressor to cycle off if the evaporator is cold enough. It might be going wonky.

teamo

Haven't done anything about the a/c yet. I am trying to take notice of when it works and when it doesn't. The weather has been cooler around here in the past week or so. I drove the crv on Thursday early morning on the way to work; the a/c was ice cold. Drove it the next day to work; same thing ice cold. Worked great both days during the afternoon. Temperature outside was in the low 80's with low humidity. Drove it yesterday, temperature was in the mid 80's. No a/c. Tried it today, temperature is in the high 80's, no a/c. Every time it has failed to work the compressor is not turning on. It seems to work when the outside temperature is lower. The system pressure is going up on the hotter days. Is there a high pressure switch that could be causing it? Either way, as has been suggested, I need to vacuum this thing down, check for leaks, then go from there.