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Intermittent A/C in 2002 olds Alero
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gavij012379
New User
May 16, 2008, 9:21 AM
Post #1 of 4
(2262 views)
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Intermittent A/C in 2002 olds Alero
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The A/C in my alero (4 cylinder, 110K) comes on only intermittently. If it is working and I shut the engine off, it may or may not work after I turn the engine back on right away. It usually works if I try it in the morning when I need it the least. Since it blows cold air when working, I am thinking the system as a whole is working fine but I have a problem with some switches or relay. All my fuses are fine. One odd thing is that once it's working, it still blows cold air even after I turn the A/C switch to off in the dashboard but leave the fan running. This has me quite convinced that this switch is faulty. But I wanted some expert opinion before I tear my dashboard. Also does anyone know how to check this dashboard switch or how to disassemble it in alero? Any help is greatly appreciated.
(This post was edited by gavij012379 on May 16, 2008, 9:28 AM)
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Tom Greenleaf
Ultimate Carjunky
/ Moderator
May 16, 2008, 1:18 PM
Post #2 of 4
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Re: Intermittent A/C in 2002 olds Alero
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This might be fairly simple! This could be the air gap for the clutch is too large and can't pull in to engage - not all that uncommon.
With everything off - keys out measure the gap - should be about .020" but don't freak out - use a std biz card and it should be fairly snug and near impossible to fit in gap when folded - how's that for rocket science?
If you can please do this safely with like a rubber hammer or wood, when it's down and you do notice the outer hub not turning just tap on it (MOVING PARTS - USE CAUTION AS IT WILL PROBABLY SNAP TO ENGAGE!!) and it will probably come on. If so the gap simply needs to be reduced. I don't know each clutch but many require a puller and use tiny washers as shims ---- that style you take one out, measure gap and usually good to go.
This could be a five minute deal or a project to get the clutch off if in a tough location,
T
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gavij012379
New User
May 16, 2008, 8:05 PM
Post #3 of 4
(2252 views)
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Re: Intermittent A/C in 2002 olds Alero
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Thank you Tom
I looked at it today and yes it is the clutch not engaging properly. Lately the A/C has been coming on when I need it. So I am going to see how long it works and be lazy..... If I start having problem then I will work on the clutch. Not fixing this problem right away should not have any ill effect on the car, right?
Also I noticed that in this car the A/C comes on automatically if the selector is in the defrost mode and also if the air is circulated inside the car even if the A/C switch is not pressed. Also if the selector is in one of these positions, just switching the A/C off won't turn it off.
Thanks again.
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Tom Greenleaf
Ultimate Carjunky
/ Moderator
May 16, 2008, 9:56 PM
Post #4 of 4
(2251 views)
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Re: Intermittent A/C in 2002 olds Alero
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Ok: I strongly think this is the clutch gap just being too wide at certain temps underhood or whatever for it's electro magnet action to "snap" it to engage. If I'm wrong - sorry - I'm not there.
It won't hurt a thing to ignore this IF it is just that. It would be wise to see if that really is the problem as this should be an easy fix - not some involved electrical problem or component failure.
Compressors in mobile air conditioning must be able to engage compressor on and off at assorted demands as compressing the gas makes it a liquid which if it tried to compress would stall, lock, choke or damage the compressor.
I'm sure you've heard a car just running and the cycling going on by itself in this or other cars.
Sorry to be so my usual "verbos" but so you understand the outer plate on the compressor is spring loaded to be OFF and when voltage get to the coil of the clutch it magnetically pulls it in then the compressor starts coing it's thing - when off that's just a pulley there. The constant on and off wears the surface some over time and miles and the gap gets too wide to pull in. Note: Outer plate is directly turning the main shaft of the compressor. When still compressor is off.
Your description was excellent so I'm not even suggesting basic electrical or pressure tests for this as you said it can work fine - great!
I don't want you or anyone reading this to get hurt with a simple test which is to just tap on that outer plate when engine is idling, A/C on asking for full performance. The magnetic force is waiting but just needs the slightest nudge and it will snap, then spin at the speed of the belt. I EXPECT THAT TO HAPPEN AND WHAT EVER YOU ARE TAPPING WITH COULD THEN DAMAGE YOU OR PARTS SO I SUGGEST SOMETHING SOFT LIKE RUBBER - EVEN HOSE OR A PEICE OF WOOD VS METAL WHICH COULD GO SHOOTING AT YOU OR SOMETHING WHEN IT SPINS. IF IN DOUBT GET SOMEONE TO HELP AS THIS IS A REAL AND PROFESSIONAL WAY TO TEST FOR THIS PROBLEM.
Again, if that works the gap is too wide and is installed new with usually one or more tiny washers to hold it at a set clearance. It is made to come off (tools and access required) and just take one of the washers out and re-install the outer plate making sure it's not then too close as to drag and it's done for years perhaps! Just didn't want you to think this is a monster expensive problem just yet.
It could need a pro to get at this and have the puller. Almost all do not require messing with the refrigerant charge or removing the compressor to do this - some do and I just don't know if this is one.
#2 Question: Compressor will engage in many cars when defrost/defog is used no matter what other temp you are requesting as a means to excercise the compressor in off season and there is some possible benefit of A/C removing moisture from the air for defrost etc., to help and IMO that is NOT the primary purpose for that. It can't work when way too cold out anyway. The idea is that oils in the system do lubricate the compressor and if unused for ages can cause early failures. Oil only travels with the refrigerant out of your sight with compressor working.
It would be nice to know if the tap test worked soon as then we could suggest what else to check and possibilities could be many,
T
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