Posted: 5/15/2008 9:44:28 AM EDT
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I have a basic question on car AC. I have a old 94 eclipse and don't want to spend a ton to get the AC working. This is an R-12 type.. The compressor turns on and there is the correct level of coolant in the car. The AC will start off cold and after 10-15 minutes it gets starts to blow at the ambient temp. Is it likely that the refridgerent just needs to be charged? There are no strange sounds/smells and everything seems fine, it just starts blowing ambient temp after 10-15 min and if I let the car sit for awhile it will blow cold again for a short time then same thing. Thanks |
I would be willing to bet on a restriction somewhere. This would cause it to freeze up and then not be able to produce cold air. ETA:With out gauge readings on high and low side pressures its hard to tell anything. |
The electric fan running when the AC is on? Try an experiment and spray the condenser (radiator looking thing in the nose of the car) with a garden hose right after the cooling stops. See if the cooling comes back. |
Anyway to determine that the switch is broken? Is it something real cheap I can just replace and see what happens?
Yes the electric fan is running. I will try the garden hose thing. I put a can of R-12 in it, it will blow cold for 10 min then blow ambient. If I turn it off for 10-20 minutes it will come back cold, then die out again. I'll see if the garden hose thing works, but what would this tell me? I didn't see any major leakage but will double check. I can take it in but it is just a beater, I got because it gets good milage and I only paid 1k for it. I just don't want to get raped at the shop. And if it is a simple fix I can do it. I just don't know a whole lot about the AC systems. But I'm ok for most general automotive mechanical stuff. |
At the very least get the car on some gauges. That will let you know what the high and low pressure sides are operating at. Any skilled technician should be able to determine if it is over- under-charge, cycling short, etc. I don't see this service costing more than $50 (but I own my own gauges so I've never had to pay someone else). Also you can pick up one of the UV dye kits relatively cheap at AutoZone, WalMart, etc. Inject the dye into the system run the AC for a while and look for the dye leaking around the fittings, compressor, etc. I guarantee if you take it to a shop they will tell you the Evaporator is leaking and charge you $1,000+ to replace. I suspect some shops lie about this and don't actually replace the evaporator. I also find it hard to believe the evaporator fails before the condenser or compressor considering the latter are under the hood and the former is in the passenger cabin. In fact the condenser is ahead of your radiator and will get damage by all the road debris and filth. Speaking of which make sure all the fins to your condenser are cleared of debris and not bent all to hell. It can't cool the hot liquid R-12 if air can't pass through it. This is what the garden hose simulates, cool air flow through the condenser. If your cabin air drops in temperature as you are running cool water through/over the condenser then your problem is there. |
You betcha. Unplug the harness and short the pins together (on the harness not the switch). This will simulate to your computer that the switch is activated and as a result sent voltage to the compressor clutch. In effect the compressor will run continously. Not recommended to do this long as the system is designed to cycle, but it will let you know if something in the control circuit is acting up. See tutorial here http://www.familycar.com/classroom/ac1.htm |
It is the 1.8 no get up and go but gets about 35mpg
Is this something I can clean manually? OR do you need special tools? |
Evacuate the system, replace the part, recharge the system. |
Kinda what I was thinking. What kind of valves are on the system? Quick connect or threaded? If you put r-12 in a r134a system the two types of oil are not compatible. May be causing excess pressure as well. You really need to put some guages on it and verify what freon is in the system. |
They also combine and form acid. Eating away at the internals of the system making for a need for a completely new system. Now if he just went to the local autoparts store to get his refrigerant then he should be good. They make the different types with the correct connectors so he wouldn't(at least it would be impressive if he did) be able to contaminate with the incorrect freon. |