Auto Mechanic Wizzards- AC question...

[Ezra Coli]

Since I'm an automotive moron, I am useless as a home mechanic. I just look under the hood and say "hmmmm..... we better have a mechanic handle this one."

My wife's Dodge Grand Caravan (yeah, she's a minivan driver, but if there's a cool minivan, this is it) has AC trouble. Last month she heard a hissing sound, she described it as a few drops of water on a hot griddle. It only occured when she turned on the AC. Over three weeks or so, the AC stopped hissing but now won't cool. It blows, but it doesn't cool. Sound simple or am I in for a soaking?

I could only guess the coolant leaked out somewhere when the compressor kicked in, but I don't know how to determine if its something I can fix myself before I take it in. Any help?:confused:

[The Body Bagger]

Look in the front of the mini-van engine on the opposite side of the alternator (big silver thing with a pulley and belt). The ac unit will the only thing under the hood with silver (chromed usually) lines on it (has a pulley and belt too and usually silver in color. Connected to the ac unit will be several lines (black +rubber) normally these tend to dry rot and come apart causing a leak of R12 or R134 (refrigerant). Look for a broken line and then go to walmart and pick up a self service coolant kit and black rubber hose with same diameter internally (externally no big deal, but stick with same size wall or thicker). Fix and service and you will be a happy man cause more imporatantly, your wife is happy.

just go here for basic questions:

http://autos.yahoo.com/maintain/fluids.html

[Ezra Coli]

Awesome! Thanks so much. If this works, I'll buy you a beer!



(beer offer only good on Wednesdays in leap years during a half moon in odd numbered months at participating Chuck E. Cheese restaurants. One per person please, void where prohibited)

[Ezra Coli]

Hey- cool avatar by the way!

[Skibane]

bagger, those are high-pressure hoses, with specialized fittings on each end - I don't think you can pick up a replacement at Wal-Mart.

Ezra, how severe your problem is depends on where the leak is. Sometimes, the rubber seals inside the compressor dry out during the winter, due to infrequent use. (In northern states, regular use of the defroster helps prevent this, but in Texas, we simply don't need the defroster that often). An A/C mechanic may be able to tear down the compressor and replace the seals, but it's probably more likely that he will want to replace the compressor. If replacing, I strongly recommend a NEW compressor, not a rebuilt (which tend to have short lifespans). You can also install the compressor yourself*.

If it's a hose that's leaking, it may be possible to install a fresh rubber hose on the old metal end fittings, thereby saving some cost. Many A/C shops have the equipment to do this. You can install the hose yourself*.

*It's often possible to save considerable labor costs by installing A/C parts yourself, but you'll almost always have to take it to an A/C shop afterwards to have them evacuate (remove all the air & moisture) and recharge the system. Usually, a new accumulator/dryer is also installed at the same time, in order to prevent any moisture trapped in the old dryer from being reintroduced to the system. Also, if the old compressor was allowed to self-destruct before replacement, it's a good idea to have them thoroughly flush the system out, to remove any broken compressor pieces, shavings, etc. that may be lodged in other components.

[The Body Bagger]

Ezra- skibane is right about the hoses. I keep forgetting my wallmart is in a commercial airlines parts room.....

And about that beer; so your telling me there's a chance............;)

[Noah Zark]

What Skibane said, plus:

Other sources of leaks are the condenser (the thin radiator for the A/C that is in front of the engine coolant radiator) and the evaporator (the "cold" radiator that is in the heater-A/C case in the dashboard.

These are made of thin aluminum tubing that is susceptible to vibration cracking and leaking. I had the evaporator go on my 92 Bonneville last year.

The wooshing sound that your wife heard is typical of A/C systems with a low charge of refrigerant. With some systems ther is a slow leak that needs topped off once a year or so. Some never leak. Some get a crack in a condenser, some get a blown rubber O-ring in the tubing fittings. It could be a number of things, but a qualified A/C shop can look over things with a UV light and visibly see fluorescent dye leak tracers, and can check the system pressures. The shop is $$$$, but your best bet.

Noah