Air Conditioning

[stevepaa]

The line that is icing up should not be icing up...It is the low pressure line returning refrigerant from the evaporator to the compressor...This indicates a bad expansion valve...The valve looks to be stuck open and is not metering the refrigerant...

maybe sometimes, but was not the case for me. I finally replaced the temperature sensor, the cheapest part of the whole repair, and all seems to be fine now. I will know this weekend when we go for an hour drive.

The old temperature never changed resistance enough to indicate a cold situation and so the compressor never cycled.

[Jerrymcc]

maybe sometimes, but was not the case for me. I finally replaced the temperature sensor, the cheapest part of the whole repair, and all seems to be fine now. I will know this weekend when we go for an hour drive.

The old temperature never changed resistance enough to indicate a cold situation and so the compressor never cycled.

Sounds reasonable to me Steve, espescilly since it worked for you...What bothers me about this one is that he said that it started out cooling and then turned warm...If the cabin thermister were not controlling the cabin temperature, why didn't it get colder instead of warmer?...It seems to me it starts out cooling until the evaporator fills with liquid refrigerant, then the evaporative process moves along toward the compressor...With all the heat under the hood, the liquid is evaporating in the return line before it can reach the compressor...The way to check it out is to wait until the line ices up again, then check to see if the compressor is still running...

[cheapo]

he said that it started out cooling and then turned warm...

I didn't say that exactly, though I can see how you'd read it that way.

Here's a recap:
After running nice and cool for 20 minutes or so, the cabin does get stuffy, but not because the vents are blowing warm air (at least not the main dash vents/haven't checked others) but because they're not blowing or are barely blowing.

A hand placed directly in front of a vent will feel a pocket of ice cold air, but it isn't blowing (despite the fact that the fan is cranked).

If I turn off the AC and wait about a minute (leaving all other settings unchanged) the vents will begin blowing cool air, presumably because the air is moving past the iced up evaporator coil. After a few minutes, all the ice melts (I guess) and the air is about the same temp as outdoor air.

Turning the AC back on gets me about 5-10 minutes of cold air...until the evaporator ices up again. (It ices up more quickly after the first ice-up/defrost cycle.)

[Jerrymcc]

I didn't say that exactly, though I can see how you'd read it that way.

Here's a recap:
After running nice and cool for 20 minutes or so, the cabin does get stuffy, but not because the vents are blowing warm air (at least not the main dash vents/haven't checked others) but because they're not blowing or are barely blowing.

A hand placed directly in front of a vent will feel a pocket of ice cold air, but it isn't blowing (despite the fact that the fan is cranked).

If I turn off the AC and wait about a minute (leaving all other settings unchanged) the vents will begin blowing cool air, presumably because the air is moving past the iced up evaporator coil. After a few minutes, all the ice melts (I guess) and the air is about the same temp as outdoor air.

Turning the AC back on gets me about 5-10 minutes of cold air...until the evaporator ices up again. (It ices up more quickly after the first ice-up/defrost cycle.)

It does sound like the evaporator is icing up...When this happens, shut it down and observe how much water collects under the car...Normally it is not very much, but if the evaporator is icing you will get a big puddle...The icing of the low pressure line all the way out to the front of the car is not normal and I cannot see how anything that goes on inside the car can cause that to happen...

What concerns me is that if liquid refrigerant reaches the compressor, the compressor will destroy itself...Liquid cannot be compressed, and the icing pipe indicates that liquid is getting past the evaporator...I, myself, would not continue to operate it until this fault, whatever it is, is cleared up...

If this car had an orifice tube and an accumulator the liquid would collect in the accumulator before it can reach the compressor...But this car has an expansion valve and receiver/dryer and it is at the opposite end of the system...One of the jobs of the expansion valve to keep liquid from flooding the evaporator...Receiver/dryers and accumulators are not the same thing...They are mistakenly described as such, but their function and location in the system is entirely different...

[stevepaa]

those were exactly my symptoms.

I could turn the blower to full and hear it humming and still nothing out of the vents. Turn off ac and I would get cold air for quite some time as the evaporator unfroze.

[cheapo]

And you fixed it just by replacing the temp. sensor at the evaporator?
Is it possible to do that without completely removing the dash?

[stevepaa]

well, after I did everything else, it still had not changed. Just changing out this sensor fixed it.

The is a 5 minute job.
Just remove the side panel below the console. Turn the slot 1/4 turn with coin, pull out and slide backwards.
Remove two screws from panel under steering wheel. Pull down to release and then pull out.

Look up in there and you will see a green connector to a white receptacle. Disconnect green plug. Pull receptacle, which is the sensor, out.

Replace.

[cheapo]

I called Volvo of Halifax to get them to order the evaporator temperature sensor and they say "That's not something we've ever replaced. Where is it in the car exactly? There are so many sensors, unless we know the part number, we won't know which one you need."

WTH do I do?

I asked: "Suppose this car had no sensors or computers and you had no Vadis. If I describe the symptoms, what would you say, based on your long experience, was wrong?" and I got a sermon on how sensor-laden and computer-reliant these cars are, and how, if there are no error codes, it's really a guessing game, and someone (me) has to pay for those guesses, which is true, but would the guesses really be so wild that I'd just be throwing my money away?

[billr99]

I called Volvo of Halifax to get them to order the evaporator temperature sensor and they say "That's not something we've ever replaced. Where is it in the car exactly? There are so many sensors, unless we know the part number, we won't know which one you need."

WTH do I do?

I asked: "Suppose this car had no sensors or computers and you had no Vadis. If I describe the symptoms, what would you say, based on your long experience, was wrong?" and I got a sermon on how sensor-laden and computer-reliant these cars are, and how, if there are no error codes, it's really a guessing game, and someone (me) has to pay for those guesses, which is true, but would the guesses really be so wild that I'd just be throwing my money away?

And this is why I will not deal with Volvo of Halifax! Try Dunsworth's down in Northwest Cove (St. Margarets Bay). It's a bit of a poke from the city but these boys know what they are doing Volvo-wise.

Good luck,

Bill

[stevepaa]

http://www.myvolvopartsonline.com/pa...layCatalogid=0

item 39 under air conditioner evaporator and heater parts.

order it from them and install it yourself.

you do have a left hand drive car, correct?

Volvo of Halifax sounds like a bunch of morons.