1999na V70 Non-working airconditioning...

[paredown]

I've found lots of threads that have information about A/C problems:

1) the 'clutch gap' problem, and how to solve it:
https://www.matthewsvolvosite.com/forums ... =1&t=39209
https://www.matthewsvolvosite.com/forums ... =1&t=39683
https://www.matthewsvolvosite.com/forums ... =1&t=31130

2) the 'failing relay on the compressor''/'thermal cutout switch':
https://www.matthewsvolvosite.com/forums ... =1&t=29275
https://www.matthewsvolvosite.com/forums ... =1&t=56831

3) system not charged fully, and low charge relay shutting system down:
https://www.matthewsvolvosite.com/forums ... =1&t=23587

4) replacing failing or leaking evaporator core:
https://www.matthewsvolvosite.com/forums ... =1&t=18166

There are probably more, but that will do for now.

I have never dealt with A/C before, so I'm looking for pointers as to where to begin to troubleshoot.

Currently I have A/C that appears not to function at all--no change in temperature when you turn it on, no sound of the compressor engaging, but also no error codes, at least from my econo reader.

This thread suggested that when the system is so low on refrigerant that the compressor doesn't cycle, the place to start is with a system evacuation to remove moisture.

If your AC system still had residual pressure in it - enough to cycle your compressor off and on before you filled it, you probably don't need to have it evacuated; it still should hold the refrigerant in there just fine. Problems arise when all of it escapes and the system and receiver/dryer fill with air and moisture.

Since I know nothing about the system I have, should I take it in to get it evacuated and tested for leaks?

Other suggestions?

[abscate]

What is the history on the AC? Working last season?

[paredown]

I bought the car at the end of last summer, and it has taken me this long to get it running reliably and get it through the test, so I have no idea about the past history of the AC system.

Since most other things on the car were neglected, I suspect it has not been working for some time.

The car has just turned over 160k...

[Ozark Lee]

The place to start is to get a pressure gauge on the system. If you have zero PSI then there is a big leak and other repairs will be necessary before you can really do anything. If you have a positive pressure but it is in the 20 to 30 PSI range you can recharge the system and either get it leak tested or simply see how long the charge lasts. As far as getting a pressure reading you have a couple of options, most of the chain auto parts stores, and even Walmart, sell R-134A recharge kits with a pressure gauge built in. They are kinda pricey when compared to just plain R-134A but it is easy. The other option is to buy a R-134A manifold gauge set. Harbor Freight has them pretty cheap at around $60.00 but I have seen several coupon sales this season where the price gets dropped to somewhere in the $40 to $50 range and Amazon and eBay tend to have them cheap as well. With the manifold gauge set you can buy the cheaper cans of R-134A which I think are in the $15.00 a can range. I buy 30 lb jugs of the stuff so I haven't paid attention to the street price of the individual cans.

A minor shaft seal leak on the compressor can sometimes be cured with some of the "stop leak" R-134A formulations. The stop leak won't do anything long term for an evaporator leak or a rust hole in the accumulator.

The next step really depends on what you find out with what your pressures are now. If you are at zero pressure the next step would be to try to pull a vacuum and see if you can find an obvious leak or at least see how long the vacuum will hold. A real vacuum pump is pretty expensive but I have home brewed a vacuum pump by installing a barb on the intake filter port on an air compressor and then running it through the gauge set so that I can see the vacuum. I draw the vacuum as deep as I can which on the home brew vacuum setup was typically about -28PSI as read on the low pressure manifold gauge.

If the vacuum holds steady for a couple of hours then you may have a problem with the Schrader valve on the low pressure port. If the vacuum doesn't hold then the real way to proceed is to charge the system with nitrogen and a small amount of R-134A to serve as a trace gas and use an electronic leak detector to locate the leak. Although that does result in "venting" R-134A it is actually perfectly legal under EPA rules since the refrigerant is not being used as a refrigerant, only as a diagnostic tool. Electronic leak detectors and nitrogen tank setups are expensive so the way most people actually do this is to buy R-134 with a leak detector dye and then use a UV light to locate the leak. Some leaks are easy to fix (a bad Schrader valve, the accumulator, or a bum O ring) and some are much more difficult to fix (a bad evaporator). Again, the tests will tell you what the real scope of the repair will be.

Before anyone gets their panties in a wad, R-134A is a HFC refrigerant which does not contain Chlorine. In theory it should have a zero ozone depletion value but the EPA can't stand anyone being comfortable so the gave it a very low ozone depletion rating and it is illegal to directly vent it. As of this moment it is not illegal to have a leak that results in the release of the refrigerant to the atmosphere but common sense and the cost of the refrigerant dictates that any sizable leak should be repaired. A leak that takes a couple of cans a year is tolerable to most people but anything much more than that will just cost a lot of money in the short term and the leak will typically get worse over time.

One way or another, get a static ( compressor not running) reading on the system and post the results back. We can assist you better once you have the numbers to work with.

...Lee

[abscate]

Adding to Lee's post. If the system is at zero pressure, you will have moisture, rust, corrosion in the components and this could get expensive..up to 1500 USD +

[paredown]

Thanks guys--once again MV site denizens get me off on the right foot...

For efficiency's sake, I may take it into a trustworthy independent to test static vacuum/leaks and then make my decision.

[Ben850]

Thanks guys--once again MV site denizens get me off on the right foot...

For efficiency's sake, I may take it into a trustworthy independent to test static vacuum/leaks and then make my decision.

That is a good idea. I plan on buying a set of manifold gauges, and a vacuum compressor.

I know I almost had the system working last year when I felt it starting to get cold. Then the rusty bottom blew out of my dryer canister in the '96 Wagon.

The gauges can be bought for the price of a technician diagnosing the leak. After his diagnosis it gets worse. I may buy the tools tomorrow, as a matter of fact, along with a new dryer canister.

I don't know yet, but I think I can also learn what I need to know about A/C systems to take care of their issues. It is one of the few things that can irk me. I have shied away all these years.

Coming soon. With pictures.

[Matty Moo]

Thanks guys--once again MV site denizens get me off on the right foot...

For efficiency's sake, I may take it into a trustworthy independent to test static vacuum/leaks and then make my decision.

That is a good idea. I plan on buying a set of manifold gauges, and a vacuum compressor.

I know I almost had the system working last year when I felt it starting to get cold. Then the rusty bottom blew out of my dryer canister in the '96 Wagon.

The gauges can be bought for the price of a technician diagnosing the leak. After his diagnosis it gets worse. I may buy the tools tomorrow, as a matter of fact, along with a new dryer canister.

I don't know yet, but I think I can also learn what I need to know about A/C systems to take care of their issues. It is one of the few things that can irk me. I have shied away all these years.

Coming soon. With pictures.

I have gauges and a vac pump if you ever want to use them. I went to school for hvac but never went into the field.

[Ben850]

Thanks guys--once again MV site denizens get me off on the right foot...

For efficiency's sake, I may take it into a trustworthy independent to test static vacuum/leaks and then make my decision.

That is a good idea. I plan on buying a set of manifold gauges, and a vacuum compressor.

I know I almost had the system working last year when I felt it starting to get cold. Then the rusty bottom blew out of my dryer canister in the '96 Wagon.

The gauges can be bought for the price of a technician diagnosing the leak. After his diagnosis it gets worse. I may buy the tools tomorrow, as a matter of fact, along with a new dryer canister.

I don't know yet, but I think I can also learn what I need to know about A/C systems to take care of their issues. It is one of the few things that can irk me. I have shied away all these years.

Coming soon. With pictures.

I have gauges and a vac pump if you ever want to use them. I went to school for hvac but never went into the field.

That is a deal Matt. I just headed out the door to Harbor Freight here in Pontiac, but it started raining so I held off.
I'm glad you posted while I was gone.
I plan on buying a couple items first. The drier canister, I'm not sure about the evaporator.
The Wagon did have a cabin filter by the way.

The compressor and clutch are fine. I still have the minor power issue to take care of at the ECC. I have that pretty well narrowed to a couple things.

I will be in touch Matt. I have a few cores for you and will supply your favorite beverage.

Thanks. These are the type of the tools you don't (shouldn't) need to use often.

[abscate]

I've thought about donating mine to the MVS tool kit for loan but don't quite know how to handle the logistics of vacuum pump and oil and shipping.

Work in progress.