ZEUS+

Glad to hear you have ice again !!! Just a tip, large pipe=low pressure.

Darien

Thanks everyone for the help!!

Just another reason I love this forum

Bill Ball

Those pressures are higher than I shoot for. They would be appropriate for a 95 degree day. If it was cooler than that, the system may have been overfilled a bit. Or it could be the system was real hot if you had run it for a long time and air circulation was not good. Low-side 21-29 and high-side 200-220 are the usual target ranges I shoot for. Here are the pressure versus temp charts from the WSM. I've anotated them with Farenheit temp and some PSI pressures.

RyanPerrella

So what did the guy do to get it to blow cold. Just measuring the pressure wont fx a previous problem, I assume the system was topped off? Was anything else done, was the receiver drier replaced or what happened?

dr bob

Bill--

I suspect that most AC "experts" don't really understand the relationship between suction pressure and evap air temp, or between ambient temp, air flow, and high-side pressure. Most just charge it until the low-side gauge reads 35 degrees, or just "put it all in" when charging from cans. Lots of system perfomance is sacrificed of course, plus overcharging risks compressor damage and certainly accelerates wear.

AC "experts" are created these days by recovery system manufacturers, using machines that are set up to be relatively idiot-proof. Suck the old gas out and condense (recover) what you can, pull a vacuum for 15 minutes, pump in the correct weight of new refrigerant. That's a great way to go with a car that has had work done on it and has all perfect components, but doesn't work to get the last critical BTU's of heat extracted from the car. The AC tech who really understands why the system works is a disappearing breed, unfortunately.

Tony

Handy Chart there Bill!
Ill have that in hand when I use the same guy.
I doubt ANYONE on here who has had there cars AC serviced has had a tech reference that chart.
This guy came out to Dariens house and made right with it all....Thats pretty cool in my book.
The price was right also.

Darien

Ryan, as mentioned previously, during the first go at it, we had the low side hose connected to the high side, which was backwards. Once we got the info needed, he came back to the house and connected both hoses to the correct ports and topped off the freon. As soon as the gauge started to turn clear, he closed the servicing hose.

The guy made two separate trips to the house, which isn't a fun drive during 5 o'clock traffic in Vegas. When he came back over, he brought an ASE Cooling System Manual and showed me how he was confused since most all other vehicles are just the opposite. Plus, he only charged me $50, which is great in my opinion

Bill Ball

I guess I'm raining on your parade, but, just to be honest, if you needed topping-off, by definition, you have a leak. It may be a slow one, but you have a leak. See if you can borrow a sniffer and take this opportunity to try to find it while you have a good charge.

Darien

Bill, I was thinking about that as well. The PO had the system replaced serviced and dye added in 2004. I'm hoping they didn't fully service it back then.

dr bob

If dye was added, all you need to do is grab a blacklight and find the leaks. There's two to three years of leak-testing evidence in there someplace!

Bill Ball

A sniffer can find a tiny, tiny leak.

So, it worked from 2004 until 2006, 2 years. How much did the "top-off" take? Did the mechanic use cans or a canister with a scale? If not, I guess you have no good idea how much.

I guess you can plan on doing it again in 2 years or less.

Go ahead and look for the dye or oil around any of the AC fittings.

IcemanG17

Bill
My A/C seems to be working fine, but I think there might be a leak in the rear A/C......when I run it (not often)...there are lots of bubble in the drier...turn it off and there is hardly any......Does the rear A/C always get a charge of freon when the system is running...or only when you turn it on?

dr bob

The rear AC system is "isolated" on the high-pressure side by a solenoid that lives under the passenger seat. The low-pressure side is always connected.

Consider that when you open that solenoid and start pulling additional heat into the system, your are also putting more load on the condenser to remove that heat. Some of the freon doesn't condense, and you see gas bubbles. You can charge the system with the rear air on and get rid of the bubbles, but this doesn't really increase the system's ability to take heat out. In fact, with the bigger charge, you may increase the the low-side pressure slightly and therefore have higher evap temps under cruising conditions. This is one reason why charging by weight is much better than charging to the sight glass condition.

The amount of freon you put in is a delicate balance between having just enough to make sure that you feed liquid to the expansion valve, and keeping the suction pressure as low as possible. The expansion valve tries to maintain the differential pressure between the two sides at the evaporator by reading the suction-side temperature, but it gets crossed up when the system is over- or under-charged. A delicate balance.

ZEUS+

Even brand new ac systems have a small amount of leakage. EPA would like a 0% leakage rate but so far it is impossible. The shaft seal to a certain degree is a constant leaker. Depending on the source it has an approximate leakage rate of 1 to 4oz. a year. Many compressors including ours have an oil wick. This absorbs oil due to leakage. Engineers figured a potential fire risk from the metal to metal contact of clutch engagement and the wick for a solution. Even the guys who make them know they leak. If a service is needed every 3 to 4 years, it just might be normal.

Tony

On that note, when recharging do you need to have the rear AC running?
I really need to get a schematic to better understand how the rear air ties into it all.