A/C question

A mechanic says he thinks I have a leak in my evaporator. When I attach a gague to the low pressure valve, it reads over 100 psi (way overfull) Is this guy a dope, or is there something I am missing.

Reply to
Surfersabo
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the compressor should be running when you check the pressures.

Reply to
Nathan W. Collier

Thanks.

I will try tomorrow. Shouldn't it read 0 if I have a leak?

Also, I am pretty adept at working on cars, but I am a supreme novice when it comes to A/C. Can somebody suggest a good book that I can read to get mor edjucated?

Thanks

Reply to
Surfersabo

Thanks.

I will try tomorrow. Shouldn't it read 0 if I have a leak?

Also, I am pretty adept at working on cars, but I am a supreme novice when it comes to A/C. Can somebody suggest a good book that I can read to get mor edjucated?

Thanks

Reply to
Surfersabo

take your vehicle to a qualified service technician. a/c isnt something for the novice. you can bullshit your way through it with the $9 pressure gauge from pep boys, but you need to fix the leak before you bother with charging the system (unless youre just looking for a temporary fix).

Reply to
Nathan W. Collier

The thing is, I would really like to learn, and what a golden opportunity now that I have a broken system (I actually have two) to get some experience.

I am not afraid to spend some money on equipment, I just don't know what to buy, or how to use it.

If what you are saying is that it is too complicated, or involved for the do-it-yourselfer I respect that I guess.

Does anybody know a way that a guy like me could learn more?

Reply to
Surfersabo

The thing is, I would really like to learn, and what a golden opportunity now that I have a broken system (I actually have two) to get some experience.

I am not afraid to spend some money on equipment, I just don't know what to buy, or how to use it.

If what you are saying is that it is too complicated, or involved for the do-it-yourselfer I respect that I guess.

Does anybody know a way that a guy like me could learn more?

Reply to
Surfersabo

The problem with AC is that you are dealing with high pressures and if you screw up, things can go wrong that can hurt you as well as damage expensive components like the compressor. Another problem is that many of the tools used for AC service and repair are pretty much useless for much else and are rather expensive. I myself look at the cost and usability of the tools and my time compared to the cost of having the repair done. If I have other uses for the tools or I know that I will need to use them again then I buy them and make the repair myself otherwise it makes more economic sense to just have the repair done for me. There are books on this stuff and if you really want to learn, I would go there first.

Reply to
TBone

Reply to
Steve Scott

So what tools are so expensive that are required to work on an A/C system? I have been working on them for years and can't think of any tool that is that expensive. With a set of gauges and a book telling you what pressure at what temp you should be looking for I can't think of anything on an auto that is much easier to do than charge an A/C system.

Yes maybe a vacuum pump but if you are a little resourceful a used compressor out of an old refrigerator with a connector on it makes a great vacuum pump and basically free.

TB> The problem with AC is that you are dealing with high pressures and if you

Reply to
user

A $1,000 you got to be kidding. Be resourceful and it will not even cost $100. Yes if you are going ot follow the law then buy the recovery system but I find that most A/C is discharged anyway when it needs work and if you have to discharge a little of what is left then just close your eyes and do it. Also remember every auto A/C system is set up to leak and will. If you have to add a can every other year or even every year that does not mean you have to get it fixed or may not even be able to fix any better that that. Any place that you have a shaft with a seal around it will leak. Now that brings up a question, Why didn't the auto industry go with a sealed compressor and operate it off a a generator that generator a higher voltage than 12 volts to keep the current down. Now that would have been more of a environment fix that saying no more R-12.

Steve Scott wrote:

Reply to
user

Lots of great information at this site:

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I learned how to do mine this summer after reading the above forum. Good luck.

Bob

Reply to
Bob M

if you have 100 psi, running or not, you probably don't have a leak

what's the pressures with it running ?

and why does this 'mechanic' 'think' that you 'have a leak' ?

low funds ?

Reply to
TranSurgeon

check your local technical colledge. the ones around here will offer "certificate" classes in automotive repair. and yes they do offer one in auto hvac.

Reply to
Christopher Thompson

i should add. i highly stress the importance of being properly educated in hvac repair. the dangers of dealing with the refigerant are hidden and apparent both. please take a class for your own information. in the mean time. take it to a shop and have a certified professional work on it. it'll be safer for you and the vehicle both.

opportunity

Reply to
Christopher Thompson

if youre _serious_ about learning more (for possibly a career?) i recommend strongly that you begin to consider a tech course. refrigeration/hvac is what i do for a living

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and its been very good to me (in addition to welding). i cannot stress enough the importance of learning right before you pick up any bad habits. i was initially self-taught and although i could get by, for the most part i was a bumbling idiot until i got some formal training. if its what you want to do youll make a lot of money doing it.....just learn to do it right by getting formal instruction. if you just want the basics, go to the library. haynes also makes a tech manual for a/c thats very basic. drop by your local auto parts store and pick up a copy.

Reply to
Nathan W. Collier

vacuum pump ($300). recovery unit ($800). recovery tank ($100), proper gauges ($100-$300). all sorts of hand tools.

i find this statement ignorant, foolish, and very irresponsible. you can _not_ pull adequate vacuum with a used compressor.

Reply to
Nathan W. Collier

So now you are no longer bumbling? It was just laying there, so I just had to.

Roy

Reply to
Roy

no, but it IS handy for pumping the system down to see if it holds vacuum

if it holds, THEN hook up the 'big dog' overnight

and, BTW........if you find an OLD one (pre about 1980), you'd be surprised how good a vacuum it WILL produce

the new ones are for crap for this use, tho

Reply to
TranSurgeon

Thank you all very much for the comments!!!

You have all been very helpful to me.

I think TranSurgeon sees what I'm afraid of with the low funds comment.

According to the mechanic, I have a leak and it must be in the evaporator, because he looked everywhere else. It could be true. It is just a very expensive repair and I would like to feel very secure that I am replacing the right part.

I appreciate the section where people debated about the cost of the tools.

I just measured the low side pressure with the AC system running and it was doing the following:

The compressor would click on and the reading would drop down to about 20, then it would click off and the pressure would rise back up to about 45. The compressor is clicking on and off every five seconds or so. Is this how the guy "knows" I have a leak?

Again, I really appreciate the help in learning about this.

Reply to
Surfersabo

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