How do you tell if a compressor is bad (or needs new shims) or if the system is low, or if the electrics are screwed up? The compressor on mine will not kick on at all. I just bought the car, and was told by the previous owner that the AC worked, but obviously doesn't. Then she said she never really used it, which I feel she had to know considering the 100 degree weather. Is it possible there is a slow leak in the evaporator? If all the pressure leaks out, would the compressor even try to kick on? I wish I would have tried adding freon before taking the intake off for the PCV problem, but now I am thinking if the compressor is bad, that it would be much easier to get out with the intake off. Is there a way to check it without the engine running?

 

https://volvoforums.com/m_58924/tm.htm

 

Right now it would be best to wait till you get the car running again.
With it running you can just unplug the low pressure switch and jump it. Then if the compressor comes on the freon level is low.

Then if you recharge it I would recharge it with dye this way you can find out exactly where it is leaking.

 

Which terminals do you jump on that switch? It appears as if there are 3.

 

That is the high pressure switch. The low pressure switch is by the firewall and only has 2 wires.

 

I put a big can of freon with oil and leak sealer, and the compressor kicked on, although it was really noisy, like a rattle noise. It took the whole can, and it was blowing cold. I shut it off, and I could hear what sounded like air escaping out the center vents, and I could also hear it where the fresh air intake is at the cowl. I put my ear up under the dash and couldn't hear anything. Now 15 minutes later the compressor no longer kicks in, as if all the freon has escaped. Please don't tell me this is a dash removal job!!

 

Sorry but yes it is the Evaperator is leaking really bad if it is all gone in 15 minutes.
Have you seen the link about removing the dash?

 

Unfortunately yes.

 

You aren't in FLA are you?

 

No, but it gets pretty darned hot here in NC! So there is no other way to access it except for a dash removal? If I do decide to tackle this, what else should I replace while I'm in there? I guess I might as well do all the o rings and switch the compressor while I'm at it. This isn't going to be fun.

 

Sorry about having to replace the evaporator.

One option for parts source:
http://www.fcpgroton.com/VolvoAC/volvo850ac.htm

Evaporator kit: $139
Receiver/Dryer kit: $49

Don't rush, take your time and allow 2-3 days for the job. Rent a car if you must; hurrying to finish a job you've never performedpreviously is a formula for disaster.

Be sure to disconnect the negative battery cable before you remove the dash, but make sure to have the radio code (if you don't know it, ask at a dealer with your VIN# and sometimes they require photo ID) and make the car re-learn idle.

You can have a shop do this too, except they want $800 to $1,000(or more?) in labour.

I wish you the best of luck.


JPN

 

You might want to check the heater core while you have it apart.

Replace the o-rings at the heater core lines as well.

It will take you 1 to 2 days to replace the evaperator.

Once you have done about 50 of them you can do it in about 5-6 hours.

If the compressor is noisy you might want to do that as well.

 

^A local mechanic at the dealer can do it in 4. But they still charge you 10-12 hours of labor for it....

 

Are there any special tools that I will need for getting the dash out?

 

^The quick connect tools are very immportant to get the lines from the engine bay off. Those guys I hear do not like to come out.

 

Where do I get these quick connect tools? Also, one thing I forgot to mention, is when I was adding the freon, when the compressor was running the gauge was in the green, but when it would cycle off it would shoot up to red. Is that normal? I would think the pressure would be less when the compressor is off.

 

Sears. Let me look up the brand.

 

http://volvospeed.com/vs_forum/index...howtopic=83033

 

I wish I'd seen that thread that you (RedTurbo) linked to before I did my compressor replacement. Those "spring coupler" connections were a royal pain. I wonder if the brand mentioned would have been better than the cheap set I bought from Advanced Auto Parts. From my experience, I had to push, pull, tug, do a jig, yell a bit and finally sleep on it and try again in the morning to get those connections apart. The next morning they all just popped off - made me wonder if there was some sort of thermal expansion happening in the springs (it was 100+ in the evening and then down around 70 F the next morning).

Also, concerning your question about the gauge shooting up to the red when filling the system with Freon: I had the same result. I eventually started timing it so that I was filling as the compressor was running. That way it stayed in the green or yellow. It didn't seem to matter if it went red because it's only that section that was under high pressure not the entire system. Once the compressorcycled on the pressure obviously dropped back down. Anyway, I agree - it made me nervous too.

Good luck with the repairs - I've been dreading having to replace the evaporator - I'm praying that mine's already been done recently or I'll be one of the lucky 0.0001% that don't have to do that job before the car completely dies.

 

Sometimes this tool mfg called Lisle makes great tools. One of them is a Torx set that fit directly on square drive (ratchet, breaker bar, etc...).

http://www.lislecorp.com/

As to A/C disconnect tools, they don't seem to have that many selections:

http://www.lislecorp.com/tool_search...ick+disconnect

Although this does not apply to 850, one of the major reasons for A/C failure is neglect; the A/C has to be used even in winter, in order to keep the seals from drying out. You can keep the heater on and still turn the compressor on too. This is the reason why you don't find that many used cars (over 5 years old) that have operational A/C.

When it comes to A/C-related topic, my head gets heated with enthusiasm....


JPN