A/C Gauge Readings

[bbhero]

It’s a bit low on r134a… Have you ever added r134a to this system ?


Get a can of STRAIGHT r134a… No stop leak number2 mixed with it.,

Weigh the can before using it.

Get a trigger r135a refrigerant add device from AZ. $26…

Weigh the can afterwards…


I added 8 ozs to my 2012 Honda and it helped a whole lot. Weighed can before and after.

And contrary to what some say…. AC sys can lose a bit of refrigerant year after year. Chris42 on here has stated that and it makes sense to me. My car being a 2012… Am I shocked that I had to add 8 ozs to it ?? Ahh no… I am not surprised by that.

I did the same darn thing with my Nissan which had a fair amount of time, mileage and age to it. Not a big deal. Worked fine. I added r134a to it 2 times in the 10 years I had it.


Most systems have between 1.2 pounds to 2.2 pounds of refrigerant in them. And losing only 8-12 ozs can make a big difference in performance of a AC system.

 

[Jango]

When I was a teenager, I topped off cars freon w/o using gauges. I progressed to using an A/C Pro red/yellow/green unit and it worked fine. Got more sophisticated and got the two gauge system and now this happens. I think I will go old school and swag it. =)

 

[Mechanician]

To be safe, I took it to a shop recommended by a friend and they said the whole system needed to be replaced to the tune of $1750. I told them I would think it over. It now doesn't run cold one bit so I called them and they said the system was empty to begin with. I pulled a gauge reading right before I brought it in and it read similar to the first picture. Were they legit? Maybe. Not sure.

The system certainly wasn't empty if you had the readings in the first photo.
They are not being honest, try another shop.
If the system is indeed now empty (you can check that with your gauges) it will need an evacuation too now. So you probably shouldn't try to fill it on your own.

 

[D60]

It’s a bit low on r134a… Have you ever added r134a to this system ?


Get a can of STRAIGHT r134a… No stop leak number2 mixed with it.,

Weigh the can before using it.

Get a trigger r135a refrigerant add device from AZ. $26…

Weigh the can afterwards…


I added 8 ozs to my 2012 Honda and it helped a whole lot. Weighed can before and after.

And contrary to what some say…. AC sys can lose a bit of refrigerant year after year. Chris42 on here has stated that and it makes sense to me. My car being a 2012… Am I shocked that I had to add 8 ozs to it ?? Ahh no… I am not surprised by that.

I did the same darn thing with my Nissan which had a fair amount of time, mileage and age to it. Not a big deal. Worked fine. I added r134a to it 2 times in the 10 years I had it.


Most systems have between 1.2 pounds to 2.2 pounds of refrigerant in them. And losing only 8-12 ozs can make a big difference in performance of a AC system.

I've wondered about this, too. By my math the little 12oz cans you buy do weigh ~12oz but the can is about 3.1 (or maybe 3.3 -- don't remember), so there's basically 9oz refrigerant in there. I think a lot of people empty them into the system and count that as 12oz, which would be incorrect by my understanding.

 

[Mechanician]

As mentioned by wag123 earlier, compressor clutch failure was a common problem on these. Complete system failure is rather rare.
That can be visually checked, for damage. Honda extended the warranty for these they were so common.
Most failed long ago, and the warranty extension has long expired.
Here is the bulletin: https://static.nhtsa.gov/odi/tsbs/2014/SB-10056005-7115.pdf

 

[Nukeman7]

I've wondered about this, too. By my math the little 12oz cans you buy do weigh ~12oz but the can is about 3.1 (or maybe 3.3 -- don't remember), so there's basically 9oz refrigerant in there. I think a lot of people empty them into the system and count that as 12oz, which would be incorrect by my understanding.

Your assumption is not correct as each can contains 12 oz. of liquid R-134a. I just weighed 6 cans on a scale and came up with 6 lbs. and 9 oz. which equates to an actual weight of 17.5 oz. per can (i.e., 12 oz. liquid refrigerant + 5.5 oz. metal can).

 

[D60]

Your assumption is not correct as each can contains 12 oz. of liquid R-134a. I just weighed 6 cans on a scale and came up with 6 lbs. and 9 oz. which equates to an actual weight of 17.5 oz. per can (i.e., 12 oz. liquid refrigerant + 5.5 oz. metal can).

A refrigerant scale or shipping scale?

 

[Jango]

I checked it again with the gauges and this is what it shows. It was roughly 30-33 and 150-160 before going to the shop.

Does this mean I need to evacuate it before recharging?

 

[Nukeman7]

A refrigerant scale or shipping scale?

I used a digital kitchen scale.

 

[RooflessVW]

I checked it again with the gauges and this is what it shows. It was roughly 30-33 and 150-160 before going to the shop.
View attachment 226076

Does this mean I need to evacuate it before recharging?

Yes. There's nothing there so rent a vacuum pump from the parts store. Pull a hard vacuum and see if it holds.

 

[Nukeman7]

I checked it again with the gauges and this is what it shows. It was roughly 30-33 and 150-160 before going to the shop.
View attachment 226076

Does this mean I need to evacuate it before recharging?

That looks out of whack! Is this at idle or with the engine off? You have a leak...unless the not-so-honest shop bled off some of the R-134a to justify replacing the entire system.

 

[D60]

I used a digital kitchen scale.

I just checked again and you're right! I'm getting 15.5oz where as before I've seen 12.3.

Does refrigerant change weight with ambient temp? Today is the hottest I've ever checked it

An empty can is 3.4oz

 

[RooflessVW]

I just checked again and you're right! I'm getting 15.5oz where as before I've seen 12.3.

Does refrigerant change weight with ambient temp? Today is the hottest I've ever checked it

An empty can is 3.4ozView attachment 226079

Weight? No. Volume? Yes.

 

[Jango]

That looks out of whack! Is this at idle or with the engine off? You have a leak...unless the not-so-honest shop bled off some of the R-134a to justify replacing the entire system.

It was at idle. Hard for me to tell if compressor was running. The shop claimed it was brought in empty but like I said I did a gauge check shortly before going there.

 

[KJSmith]

Weight? No. Volume? Yes.

How does it change volume when it in the same can?
It changes pressure.

 

[KJSmith]

I checked it again with the gauges and this is what it shows. It was roughly 30-33 and 150-160 before going to the shop.

Does this mean I need to evacuate it before recharging?

Normally, if it has positive pressure on the system, air has not got in.

The problem here is you don't know what's in the system now.
They could have leak checked it with air or nitrogen.

Using a vacuum pump is the best choice.

 

[Nukeman7]

I just checked again and you're right! I'm getting 15.5oz where as before I've seen 12.3.

Maybe there was some minor leakage of refrigerant from your previous can or it might have been incompletely filled. A few years ago, I bought a case of R-134a and one of the 12 cans was half empty.

Does refrigerant change weight with ambient temp? Today is the hottest I've ever checked it

It does not change weight with temperature changes, just pressure and volume (outside the can).

An empty can is 3.4oz

The cans I weighed were the older style without the resealable valve. Those cans appear to be made of a thicker gauge metal than my new cans with the resealable valve; hence, the slight additional weight.

 

[Mechanician]

I checked it again with the gauges and this is what it shows. It was roughly 30-33 and 150-160 before going to the shop.

Does this mean I need to evacuate it before recharging?

I was wondering (all I can do from here) if they had seen a burnt clutch, condemned the compressor, and pulled the system down to inspect the lines. And afterward decided it wasn't worth their time to put the charge back in. This wouldn't make much sense with 15 PSI in it now.

If you want to engage them further, ask them why specifically they're recommending an entire system.
Usually the only reason to do that would be a failed compressor, that contaminated the system with "black death." Carbon throughout the lines, and heat exchangers.
The heat exchangers can't be cleaned/flushed because they have many parallel tubes that can never be cleaned, since the path of least restriction is all that will flush clean.
This was a common failure on the 02-04 CRVs, with Keihin compressors.

BTW: An entire system installed for $1750 is dirt cheap.

 

[KJSmith]

and volume (outside the can).

As far as I know, any gas will expand and fill any container it is released in.
That is not unique to refrigerant.

 

[wtd]

I checked it again with the gauges and this is what it shows. It was roughly 30-33 and 150-160 before going to the shop.
View attachment 226076

Does this mean I need to evacuate it before recharging?

If this is what the gauges show with the car running, then it's almost empty which means that the shop let most of the charge out if you had the pressures you said before taking it to the shop unless some component failed on the way over to the shop and let the charge out.