98 Metro Lsi: A/C has failed after light impact

[gwem]

Hello all,

I have a 98 Metro, Auto 1.3 L with just over 100k mi on it. The A/C had been working perfectly after charging the freon about two months ago. We wad some heavy rains in the Mid-atlantic recently and I woke one morning to find a fairly large tree branch draped over my hood. It was approx 12 feet long and maybe 2-3" at the base, not exactly a twig, but not large or heavy enough to cause significant damage either. Because I take public transportation and was running a little late, I didn't have time to give the car a thorough inspection, so I eyeballed the body for dents or scratches (I found none), removed the branch and went on my merry way.

This weekend when driving the car I noticed that the A/C is not working. The blower works fine and the little amber light comes on, but I do not hear the compressor kicking in.

Is it possible the impact of the branch could have jarred something loose? An electrical connection or a belt maybe? I inspected the hood again for damage and do not see any visible dents. I suppose it's possible there was no connection at all, but as I said the A/C was serviced recently.

I have the Chiltons manual for this car, and although I wouldn't qualify myself as a mechanic, even an amatuer one, I was hoping to find a clue there, but unfortunately the space devoted to the compressor is a little brief.

I will probably take the car to a garage, just curious what might have happened and what I might be in for. Thanks in advance.

[hot_sd]

I doubt you can service the a/c with the info in the Chiltons - the factory manual has all the details on a/c repair. Anyway the thing to check also is whether the condensor fan is running. If not it sounds like a connection problem. If only the comrpessor is not engaging it may be a simple connection problem or there may be a problem with the compressor clutch/clutch coil which is a bit more complicated since the compressor will have to be removed for this and so the refrigerant will have to be evaucated and then recharged. However, make sure that the garage does try to sell you unwated repairs like refrigerant recharge or other fixes to the a/c that may not be needed.

[gwem]

Thanks. Is it possible a light bump to the hood could have caused any of these things? When I get home tonight I will check the connections a little better, the ones that are accessible anyway

[geozukigti]

Sounds to me like you have a leak. All automotive systems have a pressure switch that turns off the compressor when the pressure is too high/low. If you've got a leak, the compressor won't kick on. Kind of a self-protect thing so you don't lock the compressor up. Have the system leak checked. Or, you can buy a can of UV leak checker yourself and put it in, and do the blacklight thing.

[hot_sd]

Well if it is a connection problem and was already about to come apart then a light knock could have caused a connection to separate. Or it could just be a coincidence.

[stamar]

well you say you dont here the compressor clutch engage.

check the tension of the belt, i mean is the thing spinning the compressor. with the hood open turn on the ac does the clutch engage?

ok yes sudden loss of pressure will cause the compressor to not allow itself to turn on.

Cheapest way to diagnose is one of those things from the autopart store that has a pressure guage on top of a bottle of refrigerant. the bottle of refrigerant will help you diagnose a step further by seeing what happens to the pressure once you put more coolant in, assuming you test and dont see any.

Now ok once you know you have a leak ok... theres nothing your legally supposed to do to fix it.

Now if theres pressure in it, you know its a electrical connection belt or the compressor....

i mean now a garage doesnt mess around. the replace the compressor lol whether its a wire or not so yes knowing whats wrong before going to the garage is going to save you hundreds of dollars. many thousands over your lifetime. I wouldnt ever use a mechanic until I knew what was wrong personally.

[hot_sd]

I personally am not that keen on troubleshooting the refrigerant charge with one of those low side DIY guages. Low pressure on the suction line does not necessarily mean it is low on refrigerant - the high side reading will also help determine that. The high side and low side pressure readings can help with trying to pinpoint the fault. The method I use is to use a set of manifold guages along with a HVAC thermometer to measure the ambient and discharge temps and then use the correct pressure/temperture chart to make a determination. I have a Robinair manifold guage set (cannot remember the model number offhand but have no complaints with it). Once it has been determined it is low on refrigerant then you can try to find the source of the leak - the common methods being the use of UV dye or a halide detector. However the systen will have to be evacuated and then recharged after the repair. It is not that difficult to get EPA section 609 certification and it may be possible to rent the equipment to do the work but it is easier to have someone evacuate. However, it is best to be informed about what is wrong before taking it in for repair as mentioned.

[gwem]

Update: I really appreciate everyone's input on this. When I went home last night I confirmed that the condensor fan is not running. Will this prevent the compressor from starting? I tried reconnecting the electrical connection but had no luck with that. The blades turn freely so nothing is blocking. I was trying to trace back the wiring to see if there's anything else that may have been disconnected, but I don't see anything that's accessible that would affect the condensor fan. I will most likely be taking it to the shop tomorrow. I am fortunate enough to have a very trustworthy mechanic, who always looks for the least expensive option, so I'm hoping I don't take a big hit here. For those of those who may know, what is the cost to replace a condensor fan or motor these days?

[hot_sd]

Have you checked the fuse. If that is blown both the condensor fan as well as the compressor clutch will not operate. On the other hand if the condensor fan is gone the compressor should still kick in. To me it still sounds like a connection/electrical issue with a less likely possibility that the impact somehow caused all the refrigerant to escape and the system is not starting as a result.

[stamar]

I personally dont trust your mechanic in the least. I think if you pursue it youre going to find he just fed you the largest amount of bullshit ever. He may have diagnosed it alright, and then hes chosen to juice you for the part condenser. When its actually one of the hoses. He may have done a electrical test on the compressor to already know its ok.

you want to really trust the guy im sure. once he thinks you do though he needs to fit your ignorance around his bills. A god fearing mechanic who felt his mission in life was to work to help people who were ignorant about their cars and never learn about them( and they dont really exist, only through a charity organization)... well hed still have to sell and replace unnecessary parts for you.

If the system is no working youre damn straight that fan doesnt start. LOL. Ive actually never seen the fan in front of my condenser on my protege start. I mean ive had it for about a month only, but never. Used the AC plenty of times its just not that hot.

[jumar360]

I have the same problem (No condenser or fan) with the A/C of my 96 Metro. What happened at the garage?

[stamar]

wow

I really really want to negate the advice the person gave about buying a manifold set to analyze the pressure in your ac system. Not a worthwhile investment from where youre at, you may consider taking it to the mechanic instead.

Dont consider that, get the can with the pressure test gauge from kragen for $25. You know just about ass without seeing the pressure

when you want to get into it later get a better set, ive seen them on sale for $90. But right at the moment, you want to see leak, you will have to buy refigerant anyway, can with tester. cant see proceeding any other way.
If you really like your mechanic and you want to write him a blank check just go ahead and do that anyway, seperate from figuring out whats wrong with the AC.

[hot_sd]

Hmmm...HVAC techs use manifold guages because you simply cannot conclude that the system is low on refrigerant by looking at the low side only. If it is not low on refigerant and more is added you can overcharge the system leading to poor cooling and other problems. But of course everyone is entiled to troubleshoot and fix the a/c as they see fit. Pesonally I won't be buying the can with the guages