Recharging A/C

[mrbnatural]

I bought a 99 Contour SE in december 06. The A/C ran OK during the following summer, this year it cools down to a minimum of luke-warm (air temperature probably 80 degrees-ish) after 30 minutes of driving. I'm assuming there's a slow leak somewhere and I need to charge the system. (I can't afford to have it repaired right now, if that indeed is necessary). Anyway, so I've got my R-134a, the kit to charge the system, and I can't for the life of me find the nozzle to hook up to. I'm guessing it's that big can on the passenger side of the engine, in front of the power steering fluid container. Right? Wrong? Help! Why does the bloody manual not point these things out??

 

[Redlineracer12]

You want the low pressure port, in front of the engine more toward the driver side. The high side is on the passenger side.

To do this correctly you want to repair the leak FIRST. Otherwise you're just wasting freon (that aint cheap). But even if you don't do that you should AT LEAST use a set of gauges that monitors both the low pressure side AND high pressure side, to ensure you're not overcharging the system. That would be bad.

 

[Heywood]

As long as the system is running you don't "need" to monitor the high side. Its obviously better and all, but as long as the systems working its pretty reasonable to add a little refridgerant (1 or even 2 cans say). If the leak is fast or the system is not running or hasn't for a while then you should get it evacuated first, otherwise it won't work properly anyway.

 

[mrbnatural]

You want the low pressure port, in front of the engine more toward the driver side. The high side is on the passenger side.

To do this correctly you want to repair the leak FIRST. Otherwise you're just wasting freon (that aint cheap). But even if you don't do that you should AT LEAST use a set of gauges that monitors both the low pressure side AND high pressure side, to ensure you're not overcharging the system. That would be bad.

Well, actually, when you've got an odd 12 cans of freeon in your parents' garage that are probably never going to be used (don't ask me why they're there), freon is cheap. Besides, this is just a stop gap, I'm very certain that the leak is slow enough that one or two cans could last me the entire summer, and I only need it to last until august when I'll have the money to get it repaired.

Isn't there freon one can buy that has sealant mixed in? I used to put that in my Volvo. Is that stuff just bull or should I try it?

Oh, and lastly, yes - I have the proper gauges. Not a complete idiot here, I just act like it.

 

[LilCe98]

You want the low pressure port, in front of the engine more toward the driver side. The high side is on the passenger side.

To do this correctly you want to repair the leak FIRST. Otherwise you're just wasting freon (that aint cheap). But even if you don't do that you should AT LEAST use a set of gauges that monitors both the low pressure side AND high pressure side, to ensure you're not overcharging the system. That would be bad.

I would agree with this. Also make sure you don't have a clog somewhere. This was the case with mine last season. I kept adding freon because i thought i had a leak but I turned out to be a clogged and I almost overcharged the system and blew a compressor. I would spend the extra bucks and get a can of freon that has the gauge built into the can. That way u can tell if you're just overcharging it.

 

[elraido]

Not a complete idiot here, I just act like it.

Sorry, I had to. :laugh: Since I am 100% sure I am the only one who gets his screen name.

But onto a more serious note. I have heard of people having issues reguarding the sealent stuff messing things up even more. Something to do with either the compressor or drier or whatever.

 

[BrApple]

As long as the system is running you don't "need" to monitor the high side. Its obviously better and all, but as long as the systems working its pretty reasonable to add a little refridgerant (1 or even 2 cans say). If the leak is fast or the system is not running or hasn't for a while then you should get it evacuated first, otherwise it won't work properly anyway.

problem with that is the system takes 24 oz .... which is 2 cans .... so yeah adding one can is alittle more than reasonable being called alittle ...

 

[mrbnatural]

Sorry, I had to. :laugh: Since I am 100% sure I am the only one who gets his screen name.

But onto a more serious note. I have heard of people having issues reguarding the sealent stuff messing things up even more. Something to do with either the compressor or drier or whatever.

I use the username in a lot of places, including a URL, and when I try to explain it to people - most of them don't even know what MST3K is. You're the first.

Anyway, about my freon problem. I charged it last week and have had blisteringly cool air ever since. If it's still cool at the end of the summer, I'm not going to worry about getting it fixed (the car itself is a stopgap until I can buy a Subaru...)

 

[amc49]

Someone should really point out that if the gauge is on the can, all you're reading is suction pressure, which will read close to the same while high side may be from 150# to well over 250#. That gauge is worthless, can lead to blowing up your stuff. You use the high side pressure as the biggest indicator of where you're at. Other things matter, but if high side is not close to where it needs to be (or if you don't know it) you're risking blowing a line somewhere. As an aside, I assume that many of these systems leak slowly from the day they leave the factory. I think it comes from all the flex points with their snap connectors. They don't seal as reliably as the old solid bolt together ones did. Almost every car I've had did the slow leakdown thing in varying degrees except for one. I do not freak out and think I have to fix the leak, I just charge it back up. Good for another 2-3 years. I use all the gauges so I don't mess up anything. I don't worry about vacuum down unless system is disconnected or pressure gets below about 50#. I have made my own vacuum pump from a small air conditioner electric compressor, it will suck down to the requisite 29" to boil water. If the system just slowly leaks over a long course of time there is NO NEED to vacuum or fix leak as long as you recharge AS SOON AS you can tell the air is not cold enough anymore. That doesn't mean you go forever like that, the lower the residual pressure gets in system the closer you get to needing vac down. Now, if the leak and loss of cooling occurred all at once, you GOTTA FIND AND FIX the leak, and vac it down.

 

[Dyoel182]

Someone should really point out that if the gauge is on the can, all you're reading is suction pressure, which will read close to the same while high side may be from 150# to well over 250#. That gauge is worthless, can lead to blowing up your stuff.

No, you're reading the pressure on the low side hoses. If it was suction it would be negative pressure.

 

[larsofvt]

The Ford manual says the high side has to be above 50#. I have a cheap gauge that only connects to the low side. When I tried it, the needle fluctuated between 25# and 45# as the compressor cycled. Is that telling me I need to add R134a? Can I try adding one can without risking damage? The car is a '98 and has never been charged (I bought it with 17K on the odometer).

Someone should really point out that if the gauge is on the can, all you're reading is suction pressure, which will read close to the same while high side may be from 150# to well over 250#. That gauge is worthless, can lead to blowing up your stuff. You use the high side pressure as the biggest indicator of where you're at.

 

[Heywood]

Thats sounds about right for the low side pressures, I wouldn't try and add any more until you check the highside. Why do you think you need to recharge?

 

[amc49]

Ah, c'mon Dyoel182, clue in, it's suction PRESSURE. The only vacuum you will ever see in a normally working system is when you are vacuuming the system down before you recharge. It can still be suction because the low side is much lower than high side. Can of freon has about 70-80# in it, that's what allows the gas to flow into suction which runs from 20-25# low to 50-55# + at the suction high. That is PRESSURE, NOT VACUUM. That's why you don't necessarily have to vacuum down system if you leak some refrigerant out. Air at normal ambient pressure will not leak into a system that has higher pressure than that, talk to the physics teacher. If you are close to zero in system it needs vacuum, but much higher than that, no. The residual pressure will keep AIR OUT. A good indicator of whether you need vacuum or not is the a/c clutch. If you have leaked enough so that clutch will not come on any more, you need to vacuum system down. Clutch will shut down around 20-25#. The guy above mentioned 45# suction high, that's exactly what I was talking about in saying that the gauge on can USELESS. He could be running 130-140 ish on high side, and by adding coolant go all the way up to 250-275 on high side while only adding maybe 10 more pounds (to 55) on the low side. There's a stark heavily tilted ratio there, charging to low side numbers is worthless. The high side is how you know where you're at. Also, everybody talks in entire cans as in "can I put another can in ?". You don't go by entire cans, someday that urge to squeeze that last half can in is going to cost you big when you rupture a line or condenser core. You use the high side gauge, hit the proper number for temperature/pressure, verify proper cooling and prepare to lose that last 1/2-3/4 can of refrigerant. That's just the way it works out. There's a proper amount to put in system, its' performance decays with either too much or too little. To help prevent loss of freon like that, I will often go on a 'charging party" where I charge up all 3 of our running cars at one time to maybe save part of a can wasted.

 

[mrbnatural]

.... the few Subarus I see around drive like everybody else. I just want one because I live in Iowa, with lots and lots of gravel roads, and horrible weather, and having 4WD would definitely come in handy during the winter. And they look cool, are incredibly reliable, have much better fuel efficiency than any American car I've owned (OK, that's not saying much), and - my favorite point - are from Australia. I love just about everything from Australia. Wine, TV, Food, Cars, Women...

 

[andreslobo]

REally

REally

I live in Idyho with even more dirt roads, lots of vertical (not in Iowa), and amazing winters. My contour with studded tires gets me everywhere a sane person might want to go in the winter and so far the only place I have avoided in the summer are the fords across the rivers. The only benefit I have seen with 4wd is that they have higher towing bills due to the greater distance they go before they really get stuck.

 

[larsofvt]

Oh,

It's because the system does not seem to be cooling that well. It works, but on days we had in the upper 80's it couldn't keep up.

Thats sounds about right for the low side pressures, I wouldn't try and add any more until you check the highside. Why do you think you need to recharge?

 

[Heywood]

Oh,

It's because the system does not seem to be cooling that well. It works, but on days we had in the upper 80's it couldn't keep up.

Then I would get hold of a proper gauge set (rent from autozone or buy for 60-80 bucks) and check out the system pressures, and possibly add some more refridgerant (but not a whole can). You might find it helpful to have a thermometer handy to check the temperature of the air coming out of the vents. If you search around here, last time I was asking about this someone quoted some vent temperatures.