2003 Subaru - While It's Apart...

[tjm]

This is my first post. Hello to all!

I have a 2003 Subaru WRX. It was bought as a project car. I can guarantee nothing about what has been done or by whom.

I am not an A/C tech. At best I'm a guy who doesn't know his own limitations. I am learning. I have a set of gauges and a borrowed vacuum pump.

I know a guy with a shop and all the cool recovery tools. The less he has to do, the less he charges me. At the end of last summer he vacuum tested the car, declared it sound, and charged it with refrigerant. I didn't know how the gauges should read back then but he was confident that the compressor was fine. However, no cold air came out, he got very sick, life got in the way. Winter came & went. This week I put my gauges on it and found zero PSI. I found 2 leaking O-rings and a bad schrader valve. It holds vacuum now. I bought a new accumulator because all the cool kids do it. I bought an expansion valve because that seems like it could be where the hang up was, it was inexpensive, and I'll never have another chance like this to do it cheaply (no coolant in the system).

I know, I'm long winded. But while I have this thing open and don't have to pay anyone to evacuate the refrigerant, is there any possible to way that I can test the compressor. I don't think so but I thought I would ask.

[Tom Greenleaf]

OK, I dare say low charge is still the #1 reason for poor or no cooling. Please do know that understanding A/C is a total course of study never mind each specific vehicle but will tell of some basic reasons more than you found real leaks and things to know.

Holding a vacuum is a must or don't proceed. Do know just that is only holding OUT 14.7 PSI of atmospheric pressure, conversely when properly charge the system is holding in pressures into the 100s so a huge difference. Just means can hold the 14.7 one way but may not the other.

This is newer as things go so uses less refrigerant than ancient days now so ability to charge to exact specified weight of charge is mandatory. Just off by 10% will change the whole works now that's just a small amount near impossible to measure without the equipment.

It's costly because both the knowledge and OMG cost of equipment would scare you blind techs simply have to charge some $ just to have that.

In short it's not DIY friendly or cost effective. Worse is mistakes cost disasters you didn't even have to begin with so AYOR if you take this on without a strong understanding of what you are doing and with what type of equipment.

A #1 warning is don't be fooled by kits that just show it's all wonderful on a gauge it's not even close to the simple.

Also know that contamination of any sealers is going to confuse the diagnosis up to its own disaster - avoid that. Air can't be allowed in the system just hooking up hoses can spit air in if not paying attention.

Basic again: Flow when hooding anything up is higher pressure runs to the lower when thru gauges is at your control to hold or stop it and just observe.

Step 1 when it holds a vacuum perfectly is charge it to exact weight and then know system is operational at all. If more leaking is present that's the time right away to find those and repair means also starting all over with vacuum and charge up again.

Nobody wants to waste $$ or overspend just beware you can cut off your nose to spite your face and costs will skyrocket for a real fix!

I can type away or find you links for info buy you need some serious understanding of how it works first. It's just another thing that knowing 1/2 of how it works is worse than knowing nothing about it,

[tjm]

Ah, maybe I can say this better. I have an acquaintance with a shop. He has a recovery system and can put an accurate amount of coolant in. He did this last summer and the compressor started turning and he liked the readings on the gauges. Sadly, I hadn't bothered to learn the basics and couldn't tell you what readings he was seeing. Everything seemed fine but no cold air came into the cabin. We made an appointment for round 2 but he got very sick and I got busy. Last week I bought gauges and saw that the pressure was zero. Someone put dye into the system at some point and I easily found two O-rings that were leaking. I bought a kit of O-rings and replaced them. I borrowed a vacuum pump and quickly stressed one of the Schrader valves to failure. I replaced the Schrader valve and it held vacuum for an hour. I bought a new expansion valve because they seem to be weak on this car, they are cheap, and while there is no refrigerant in the system I don't see why I can't replace it and vacuum test again. The same for the dryer. I'm sorry if it strains credulity to think that I can bolt some new parts on and test for vacuum on an empty system. When the new parts are on I will probably take it back to my friend to add refrigerant but his time is valuable and I was just wondering if there is any test that can be done on the compressor now while the system is evacuated?

[Cornbinder89]

As long as compressors have the right amount of oil, and the system is charged correctly, they rarely fail. When they do fail, most times it is from running without oil, or enough oil. Compressors are cooled by the returning refrigerant, so when the system is low, less cooling takes place.
Any leak can carry oil out with the refrigerant, as it is soluble in it.
If you don't know how much oil is in the compressor after all the leaking, it would be a good time to pull the compressor, drain and re fill with the correct amount and type of oil called for. Pag oil in particular is hydroscopic, meaning it will absorb moisture from the air, so needs to be in air for the minimum time possible, measure it in, seal the system, evacuate and charge in the shortest time possible.
Beyond that, it going to take diagnosing of why things aren't cooling.

[tjm]

Thanks. Now we're getting somewhere.

So, if I do that, there is still oil in the evaporator, condensor, lines, whatever. Will the vacuum boil the water off from the remaining oil?

[Tom Greenleaf]

Quote you ">Will the vacuum boil the water off from the remaining oil?<" Cornbinder already said that PAG oil(s) are 'hygroscopic" and absorb moisture even from just air. Problem is if enough that oil remaining can go acidic and be the horror show as it circulates around and around while running. Water/air if just that simple would boil as vapor unless by chance you are at the N. Pole now and most oil remains that was left. Counting how many ounces after a failure is educated guessing. Like how much of a mess did the known "O" rings make? The Shrader leaking? Where is it located? if low in system may not make the mess.

Other items when replaced the general rule is dump out oil from old parts or ones removed that are being used again, count that and measure it. Add that much back and usually a couple oz. more oil.

Trying to be concise for you. There's no dipstick for oil level it's done once then keep track. When you can't the only way to know is flush everything and start over with the OE specified amount. Do NOT flush compressors but do spin oil thru them if off vehicle or replaced before it's allowed to work for real.

Wish oil absolutely showed it was full of moisture and I'll just say NO the vacuum will NOT pull moisture out of the remaining oil? Had some discussion on that - the old site. High bet only that moisture (it is water) could only come out of hygroscopic oil if you cooked it - a guess on my part.

OK - so just that question if you don't flush it all out you are taking a chance of shorter life of the system! Not just one or two parts it would be the horror show to avoid if known a risk.

Side note: Most all vehicles that need to much where I am AND have just catastrophic failure ask to simply disable compressor or by-pass it (kits made if a must) so it can't take out belt(s) when is blows up and would if it tried too long.

All part of the joy of A/C and how costly it can get! Scary,

[Cornbinder89]

York and some Sanden are the only ones I know of that have a dipstick for oil level. Harrison A-6 can be checked through a port on the side, but if charged, you need to only loosen, and see if oil comes out with a little refrigerant. .

[tjm]

I'm not ignoring what was said about flushing the oil and starting over again. I'm not sure how I would get it out of the evaporator but I will read up...

Not for nothing, but what really bothers me about this car is not knowing who did what to it previously. I have the specs on how much oil it needs. So if I dump out an ounce from part X and put and ounce back in, well, that's fine but only if it was done right previously (and the rest of the oil isn't acidic). The parts I've removed so far indicate that someone thought going 'all gorilla' on the bolts would somehow make the o-rings seal better. So either I don't understand how an o-ring works or there has already been some questionable work done.

[Cornbinder89]

Most nuts are steel, most tube is aluminum, will a little corrosion they can be very hard to remove, doesn't mean someone overtighten them. Since I have a hose crimper, and some fittings, I often slit the fitting nut with a hacksaw blade to separate and then replace the fitting

[Cornbinder89]

If your serious about doing A/C work a crimper is almost mandatory, along with a vacuum pump, can tapper, sniffer, and a set of gauges. A scale would be good also.
Without those things it is cheaper to let someone else do the work, than risk breaking a hard to replace part like the evaporator.
Just because stuff "should" come apart, doesn't mean it will. Often the best solution is to sacrifice the easiest to replace part to save the hard to replace part. Hose fittings fall under the easy to replace part if you have access to a crimper and fittings.
When I bought my crimper they were between $600-$700 now you can buy from Master-cool for less than $200. Even with paying what I paid, that crimper has saved me money. Of course it wouldn't if I was buying for just one job... see my point?

[tjm]

Well, I'm a crimper and a sniffer away.

Seriously, my goal is to get my son through a couple more years of college with air conditioning. If I break something it won't be first time or likely the last. Nothing burns knowledge into my brain like paying big bucks to do it right the 2nd time.

My other goal is to understand the system a little better. I hate just grunting 'cold air no workee' to the service manager and hoping for the best. I can tell you for absolute certain that there are pros in this town who will be glad to get this unit working with no concern for how much oil is in it.

I got the new expansion valve in last night and it held vacuum. Now THAT is a job for a 90 lb. kid on this car, not a guy in his 60s. I feel like I did 200 sit ups last night.

[Tom Greenleaf]

OK, if you are going to jump in I think you are aware of risks of making it more costly. Hey - space is too costly to own way to much where I am so that matters and season shorter or longer for folks specific needs and wants.

It's declining here just too costly for specialty shops I think just one I could just get part of what I'm doing done, make the mess there, finish up at my shop. Conjures the thought you should fix a known issue off season most shops don't heat enough to finish with testing how it all works get a garage super hot, vehicle and all duplicate conditions I've done hat just a couple times not really worth it but a challenge.

Here's some info always more could be added there's just so, so much to know more is unique to each vehicle then by model years too! Uggg - when it what supposed to do what the info isn't free!

Worth the read the link in there is back to here another place I'm at click > http://autoforums.carjunky.com/Autom...YSTEMS_P45460/ < that it's locked for read only.

When in doubt you should be thinking when to stop, think and minimize damage to nothing if possible so you can start again later.

Just beware of endless videos on how to do what a lot are plain wrong there's no safeguard against bad info out there! Just means you need to build your own understanding so you can sort out junk info from real.

Said already or many times just really watch you can pull a full vacuum and do anything not to allow air back in. Measure what goes in to known specification have what it takes scales can do. Once at 80% (my guess) you get cooing can slow down for the finish. Last bit doing it with a running system you do need to keep source of refrigerant warm or it wont move to higher pressure.

Other is spray water on condenser will drop system pressures in vehicles but the pressures are too low if reading them to declare much is correct just the trick to get last amounts in if necessary. Pan or bucket of warm (not hot) water is useful.

Here to help if you are up to going for it. Stop and ask if not working out as expected,

[tjm]

Very cool! Thank you. Whatever I break is 100% my fault.

The new drier was way harder to install than I expected. I'm not even big handed and it was fiddly beyond measure. The vacuum pump is running now. It looks like I'm going forward. But my a/c guy has gone home for the day and I am too tired for a DIY learning experience. Right or wrong, I'm going to leave it under vacuum for the night. If it breaks something it's on me.

[Tom Greenleaf]

Too late perhaps now but you don't need to leave pump going constantly, just check when it's a full vacuum, run again if you wish and let it sit. That should hold tight if not perfect 1st don't trust the gauges or hook ups then on to where. See, if moisture was still evaporating to vapor pressure would creep back up and go get that but point is NOT all night running you can't make the call with it running,

[tjm]

No, no, I'm not the kind of guy to abuse a borrowed pump. I turned it off after 30 minutes. I never heard of anyone leaving their system under vacuum so I was in uncharted territory. I knew I was too tired to finish and I read repeatedly that it isn't that hard to ruin a new drier. It wasn't that expensive but it wasn't something I want to do again.

[Tom Greenleaf]

OK - great. It's subject to disagreement I just hear of people leaving the pump on for endless hours. Full vacuum should be in a few minutes if a faster one or more. Hold that is what counts is proof if you believe your gauges. Could have said do it with a warm engine is a tad better.

There are charts or I'll find them here someplace. Full vacuum at sea level is 29.92 Hg. That's inches of mercury. Most gauges will just peg at 30 for me altitude counts so know that. I'm at 232 ft. above sea level doesn't show up so little. For each 1,000 ft. you can deduct 1 Hg. is full vacuum all that unless equipment is compensating or some display. Major pest for me to quick use some other type of something, even a brand gauges or pumps just where they are locking in or out pressure or vacuum.

Sorry to carry on my best stuff you can "park" hose ends and just read vacuum without a vehicle but cost more than some cars! Nice too easy to vac out gauges they also can do both R-12 and 134a start with gauge hose empty either way even when charge time comes,

[tjm]

Just a courtesy post since it doesn't seem right to disappear after getting so much free advice...

Thanks for the help. It didn't work but it reminded me how much I enjoy learning new things. I replaced the dryer and the expansion valve since it seemed reasonable at the time (system was empty). The expansion valve was brutal and I am 5' 9". I don't even want to think how tough it would be for a larger person. I replaced a couple of leaking 0-rings and a Schrader valve that broke under vacuum. It held vacuum. But by the time I had it back together enough to charge it was Saturday and my pro was home enjoying life, at least I hope so. Eager to flush money down the drain, I bought an 18 oz. can of 134a and a tap. I used the procedures in the link provided in this thread and charged it.

I think it may need a compressor but this is where DIY ends for me. I'm not a 'nobody's looking, vent to the atmosphere' kind of guy so I'm headed to my pro tomorrow. The high side doesn't get very high and the low side seems way low. At some point in the process I see the gauges start to move but the compressor slows to a halt and the belt slips. The belt IS properly tensioned.

If anyone is bored and enjoys teaching a fool I'd be glad to post a video. As I said, it's going to a pro. But I wouldn't mind learning more. My guy is really busy sometimes and he may have me replace the culprit. I provide him both income and entertainment.

[Cornbinder89]

Before you give up, replace the belt with the one called for. I have seen 7/16" (11mm) belts used on 1/2" pulleys and they will bottom out and slip regardless of tension. If it is a one serpentine belt, when was the last time it was changed? Until the compressor is turning all pressure readings are moot..

[tjm]

What the heck, a new belt isn't going to break me. I'll do it. This belt drives nothing other than the compressor and it has about 18,000 miles on it since we rebuilt the engine.

The compressor IS turning. I can see the clutch engage, the compressor turns, and very cold air comes into the cabin. Then something happens, the compressor slows, then stops, and the belt squeals. Then the compressor starts turning again and the process repeats.

I didn't get video of the compressor stopping but you can hear the belt squeal - https://vimeo.com/330307782

I have the factory service manual in front of me. It says that at 86-95 degrees F the low should range from 18-21 psi and the high from 213-242 psi. It was only 70-71 degrees when I shot the video but to me it's screaming that something is not right.

[Cornbinder89]

I never put much stock in "should be" pressures charts. The high side pressure of a properly charge system show the condensing temp of the refrigerant. the low side shows the evaporating temp.
Condensing temp will never equal ambient temp of air passing thru the condenser, but the closer you can get it the better the system will work. 134a will condense at 144 deg (242 psi) so that is roughly 50 deg over the ambient of the 95 deg stated. That's fairly poor heat rejection from the condenser.
I am much more interested in what IS happening and why. If the system isn't getting the heat out, that needs to be solved.
The pressure vs, temp charts for both R 12 and R134a are posted in the reference and resource section of this site.

Put another way, gauge readings show you what is happening in the system, charts show what you might expect under some condition the chart maker used, the 1st is of much more use than the 2nd.