Calling auto AC guys

Tech questions that don't fit above forums

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Truckedup
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Calling auto AC guys

Post by Truckedup »

2002 Honda CRV 5 speed, 130,000 miles. The ac comes on normally and gets cold quickly...after a bit it goes from cold to moderately cold , the compressor is cycling on an off. When you stop for more than 10 seconds, the compressors cycles off and won't come on until you drive away or raise the rpm up to 1500 while stopped. Can drive for hours and it just keeps cycling but cools the interior just ok...
Both cooling fans are running, the condenser is clean.
I put a gauge set on it...at idle the low side is 40, the high side is about 90, air from the interior outlets is not cold.. Increase the rpm to 1500 ,the compressor cuts in, low side shows 10 psi, high is 100 psi. Cold air from outlets.
I do know just enough to add some 134R, I have done it on my other junkers...I hooked the can to the middle hose, opened the valve on the can and the manifold low side...But it won't take the 134...the car ac line ports are clean. A very small amount of 134 leaked from the high side port when I made the connect to the gauge hose. It was green and a bit slimy. Could this be sealer put in by the previous owner?
What is your opinion on this , thanks
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Re: Calling auto AC guys

Post by 77cruiser »

Is it a can you have to tap? Or is it the can with the hose already on it?
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Re: Calling auto AC guys

Post by turbo camino »

It's considered 'normal' for an AC system in proper operating condition to lose as much as 1/2 a pound of refrigerant every year.

134A systems many times have such small capacities to start with that losing a little bit can have a big impact on performance.

There are some things the DIY guy can do at home with some twine and old coathangers, 134A HVAC is not one of those things. With the small system capacities, you are relying on a best-guess if you try charging it without a scale. Adding refrigerant to a partially-charged system is even more of a wild-assed guess than trying to do a full charge from empty without a scale. How much is in there right now? Who knows!? How much did you just put in? I don't know! The numbers on the gauges look kinda OK? That's good enough, right? ....right? No?

To do this in a way that isn't dependent on luck, you need a proper recovery machine. Those are expensive. It's not a waste of money to pay someone to do the recover/evac/recharge for you. The only way to do it in a way that isn't just guessing is to recover what's in there, and recharge with the proper amount. It takes about 15 minutes if the system hasn't been opened to atmosphere.
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Re: Calling auto AC guys

Post by Truckedup »

77cruiser wrote: Thu Aug 06, 2020 9:45 pm Is it a can you have to tap? Or is it the can with the hose already on it?
Tap the can...I'm am aware that just adding 134r by relying on gauge readings is not the best way...But it has worked for me in the past...this is a $2000 car....
Based on my descriptions of system pressure I wondered if anyone had an idea of what could be wrong..
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Re: Calling auto AC guys

Post by 77cruiser »

Do you have the right tap? The pointed ones don't work on self sealing cans. Just found that out couple months ago when charging my car.

https://images-na.ssl-images-amazon.com ... L1500_.jpg
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Re: Calling auto AC guys

Post by turbo camino »

With the system capacity being so critical, often the very first step in diagnosis is to recover the system for no reason other than to see if it's low or not. There are so many conditions that can cause the pressures to mimic low refrigerant, and low refrigerant to mimic other conditions, that determining the actual system charge is the only way to tell if there is a problem that needs fixing, or if it just needs the correct amount put back in.

Believe me I know what I'm talking about here - being retired and not having access to shop equipment anymore, and being poor and not able to buy a recovery machine for my own once-every-other-year use, I too have to pony up and pay someone else to do AC work for me. It sucks but that's just how it goes.
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Re: Calling auto AC guys

Post by Truckedup »

turbo camino wrote: Fri Aug 07, 2020 9:30 am With the system capacity being so critical, often the very first step in diagnosis is to recover the system for no reason other than to see if it's low or not. There are so many conditions that can cause the pressures to mimic low refrigerant, and low refrigerant to mimic other conditions, that determining the actual system charge is the only way to tell if there is a problem that needs fixing, or if it just needs the correct amount put back in.
..

Believe me I know what I'm talking about here - being retired and not having access to shop equipment anymore, and being poor and not able to buy a recovery machine for my own once-every-other-year use, I too have to pony up and pay someone else to do AC work for me. It sucks but that's just how it goes.
Yes...I just had my Ranger ac repaired . Rusted accumulator and the high pressure hose also rusted through...600 bucks and it works great. I'm retired and the Honda is a good beater..needs low cost repairs by me
77cruiser wrote: Fri Aug 07, 2020 8:48 am Do you have the right tap? The pointed ones don't work on self sealing cans. Just found that out couple months ago when charging my car.
Damn, I got the wrong tap, thanks
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Re: Calling auto AC guys

Post by dannobee »

Don't the Honda CRV's have a sight glass in the liquid line? On the RH inner fenderwell. If so, it makes it easier to charge at home. And if you need a scale, Amazon has accurate digital scales for less than $20. Don't overthink this, having a charging and recovery station is nice, but not 100% necessary.
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Re: Calling auto AC guys

Post by 6.50camaro »

Do a goggle search for 134a pressure temperature chart . It will give you a rough idea of what the low and high pressures should be at a given outside air temp . Ex. @80 degrees lowside should be 40 -45 high side should be 210-250 . This is constant running presures . It sounds like you are low of it drop to 10 psig the compressor is cycling on the lowpressure saftey swicth . Dan
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Re: Calling auto AC guys

Post by 6.50camaro »

If the car is not running both sides equalize to the same pressure . You only have pressure difference if the compressor is running Dan
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Re: Calling auto AC guys

Post by 6.50camaro »

77cruiser wrote: Fri Aug 07, 2020 8:48 am Do you have the right tap? The pointed ones don't work on self sealing cans. Just found that out couple months ago when charging my car.

https://images-na.ssl-images-amazon.com ... L1500_.jpg
They do sell adapters to use the older valves on the new self seal cans .Dan
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Re: Calling auto AC guys

Post by 77cruiser »

I bought mine from Amazon but after looking I could have bought it at Oriellys
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Re: Calling auto AC guys

Post by Truckedup »

I got the correct tap. About 80f outside. Hooked up the cheap gauge set and a 134r can..With the compressor running its now 40 on the suction side and 160 psi on the pressure side...The pump doesn't cycle excessively when the car is driven. At idle it's less cold but much better than before. It's good enough for a 19 year second car.....Thanks for the help....
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Re: Calling auto AC guys

Post by 6.50camaro »

If you got any refrgerant left it could use a little more high side should be just over 200 psig , if not and your happy with it thats fine. Just saying it could be a little better. Dan
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Re: Calling auto AC guys

Post by 77cruiser »

I'd try a little more. I'm not an AC guy but my car won't cool good till it gets to about 250 on the hi side. my 04 truck goes up to about 350 & when I checked the temp out of the vent driving down the road it was 36 deg, it's never had any added to it since I bought it.
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