Topping off an Auto A/C?

[aspeck]

If after adding the Freon the system still doesn't seem to be cooling properly, you could have a plugged expansion valve. And before getting too excited, those things are really cheap and mostly plastic thin little sections about 5" or 6" long that fits inside the tubes. I've replaced them before for less then a few dollars. BUT, you have to break open the system to get to it because it is usually in the evaporator that is inside the vehicle. How it works is the Freon entering the evaporator has to flow through the expansion valve and that allows the Freon to expand and that sucks the heat to accomplish that. Then the fan blows across the radiator like evaporator and you get cold air coming out. And if there is any contaminates in the system, the expansion valve gets plugged up and restricts the Freon flow because of the very fine screen used in them. I've seen them totally covered in black particles where they couldn't pass anything though them anymore...So just a little info...

Understand that it is a CLOSED system, so if the expansion valve is plugged, it is probably because the desicant (sp?) bag has broken, or a seal is disintegrating. In other words, you have other issues going on. Unless you are an A/C specialist, you might want to have a professional look at it. Home fixes will only prolong the inevitable for so long ...

 

[MTboatguy]

I buy my 134a at Home Depot, it stays the same price year around, here it has been $6.98 a can for a couple of years ago, runs about $9.00 at Wal Mart and is like $12.00 at the auto parts store.

 

[bruceb58]

Understand that it is a CLOSED system, so if the expansion valve is plugged, it is probably because the desicant (sp?) bag has broken, or a seal is disintegrating. In other words, you have other issues going on. Unless you are an A/C specialist, you might want to have a professional look at it. Home fixes will only prolong the inevitable for so long ...

+++++1

 

[Idlespeedonly]

Very rarely will you ever see an expansion valve plugged. Usually the condenser will filter the big stuff out.
Orifice tube, they stop up all the time.
And if the orifice tube is plugged you will more than likely need a new compressor pretty soon.

 

[gm280]

MTBoatguy, I honestly didn't even know that Home Deport sold Freon. So I may have to take a look. I usually don't go to HD, I go to Lowes.

aspect, you are right about having other issues if the Expansion valve is plugged. I have changed a few compressors over the years as well, condensers and evaporators. :faint2: Not my favorite thing to do... I have even bought kits with all those things included and rebuilt AC systems. But I still would rather do such myself instead of handing an AC shop near $3000 dollars to repair it. A few hundred is a lot easier on the pocket book then a few thousand.

JMHO!

 

[rogerwa]

This the way I look at it. for my kids cars, if the AC isn't working, I will hook it up and feed it a can. If it bleeds it out they ride in a hot car. I didn't have AC as a kid in my car - its a luxury. I'll give it a shot for $10 but thats about it.. The cars my wife and I drive are newer and don't have leakage issues or are on warranty.

 

[oldboat1]

Boomyal -- happens we just used my sis in law's Explorer for most of a week (muggy, touching 90s). I thought the A/C was a little underwhelming -- kept cranking it up to high fan speed, and kept it on max. I sort of had the idea that the vehicle might not have a great circulation system for its size -- tough time keeping up in the heat of the day. But maybe it needed some service.

It's probably worth having a shop draw it down and refill it, at least the first time around. That way you will at least know whether it's at its best.

 

[Boomyal]

Boomyal -- happens we just used my sis in law's Explorer for most of a week (muggy, touching 90s). I thought the A/C was a little underwhelming -- kept cranking it up to high fan speed, and kept it on max. I sort of had the idea that the vehicle might not have a great circulation system for its size -- tough time keeping up in the heat of the day. But maybe it needed some service.

It's probably worth having a shop draw it down and refill it, at least the first time around. That way you will at least know whether it's at its best.

oldboat, I did buy an 18 oz can of R136a, with a gauge and put it in. What I was not aware of from inside the vehicle was the the compressor was cycling on and off. You just could not hear/feel it doing so from inside the vehicle but it still did blow somewhat cold. It took the full 18 oz can and the compressor quit cycling. I went and bought another 12 oz can and about half of that got it up to the proper pressure. After that, the A/C was blowing as cold as I thought it should. It had probably never been recharged in it's 9 year life.

I will wait a bit and throw the gauge back on it and see how it held.

 

[gm280]

oldboat, I did buy an 18 oz can of R136a, with a gauge and put it in. What I was not aware of from inside the vehicle was the the compressor was cycling on and off. You just could not hear/feel it doing so from inside the vehicle but it still did blow somewhat cold. It took the full 18 oz can and the compressor quit cycling. I went and bought another 12 oz can and about half of that got it up to the proper pressure. After that, the A/C was blowing as cold as I thought it should. It had probably never been recharged in it's 9 year life.

I will wait a bit and throw the gauge back on it and see how it held.

Boomyal, that also make a colored UV dye that you can put in. It usually takes one or two shots of the dye and then if there are any leaks, you can use a UV light at night and see where the leak is occurring from. The dye goes in at the same play the usual R134a Freon goes, but only a very same amount, not the entire little can. Just some info!

 

[NYBo]

oldboat, I did buy an 18 oz can of R136a, with a gauge and put it in. What I was not aware of from inside the vehicle was the the compressor was cycling on and off. You just could not hear/feel it doing so from inside the vehicle but it still did blow somewhat cold. It took the full 18 oz can and the compressor quit cycling. I went and bought another 12 oz can and about half of that got it up to the proper pressure. After that, the A/C was blowing as cold as I thought it should. It had probably never been recharged in it's 9 year life.

You have a leak.

 

[oldboat1]

The compressor action (recycling) is usually my clue that I need a recharge ('96 S-10) -- and get obsessive and use a thermometer at the center outlet. I've done the off the shelf recharge on occasion, but over the last couple of seasons have left it to the shop when in for regular maintenance. Think you are on track to test it out a bit and see if it holds after adding a charge. 24 oz is a lot to add, so think you have a leak, but better to get some in there to lube up the system and see how it holds up.

 

[Boomyal]

The compressor action (recycling) is usually my clue that I need a recharge ('96 S-10) -- and get obsessive and use a thermometer at the center outlet. I've done the off the shelf recharge on occasion, but over the last couple of seasons have left it to the shop when in for regular maintenance. Think you are on track to test it out a bit and see if it holds after adding a charge. 24 oz is a lot to add, so think you have a leak, but better to get some in there to lube up the system and see how it holds up.

At 24 oz, I think it was about half empty. It is a dual air system. Also, because the air still seemed to work ( a bit less than ice cold) I would not be surprised if the charge had ever been checked or added to. But we'll see, in a month or so.

 

[oldboat1]

sounds on track.

 

[Harritwo]

Boomyal,

Get a IR Thermometer and see what the temp is on high, Max,after a few minutes. On those Explorers does it have the Dual A/C or just the main controls and vents up front. Most without the Rear A/C take forever to cool and still seems like it isnt cooling. A lot of it is the Heat Load in the vehicle. R-134A does not get as cold as R-12. With the 24 oz you put in, it was definitely low.

As a Public Service Announcement, Big Lots has R-134 for about $6.00-$7.00 a 12 oz can year round. Most of the time you have to ask for it as it is behind the counter.

 

[oldboat1]

^^^That's an interesting note on experience -- same as what I had using a borrowed Explorer last week. It just seemed like it wasn't effective (was looking for more vents, thinking my sis in law had closed off one or two).