Once again, my freon has leaked down to a point where the AC cycles every 5 seconds and cooling at any speed is nil. There is still pressure in the system.

QUESTION:

How many V/S70 owners have had the evaporator replaced and solved all problems?

I change the cabin filter regularly so I am wondering if the evap has a leak or could it be somewhere else. The accumulator does not appear to leak, no yellow dye on the outside. I suspect the low port schrader valve 'might' be a problem, but that is not confirmed - yellow dye is present but could have been there after putting it into the system.

I really don't want to have to spend a couple of days tearing the car apart and find the evaporator is pretty good shape.

By the way, I charged the system last October and it lasted until it got hot this week.

Aaaarrrrrrgh...

Klaus
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Always willing to listen, just not able to take direction.

Have you tried spraying soapy water on the low pressure side Schrader valve?

Back when I had a '92 245 with AC problems I took it to a shop for diagnosis. The tech started out looking for leaks with an electronic sniffer, but soon gave up when he couldn't find the source of the leak.

He evacuated the system, pressurized it with nitrogen and then sprayed each component/hose with soapy water. He found a pin-hole leak in a high pressure line that the electronic sniffer failed to detect.

I realize this wouldn't work well for the V70 evaporator, but it might help you in a process of elimination. It should be straightforward to do, given that your system still has some pressure.

Good luck!

Schrader valve leaks are hard to diagnose, especially like mine that only leaked under high pressure: >60psi or so. Which means the system held enough pressure to cycle the clutch rapidly, but not enough to complete the cooling cycle.

I had the schrader valve replaced when I noticed bubbles of R134a as soon as I removed the dust cap. The dust cap may have held a slight amount of pressure, but once the valve was replaced - no more major leak. The system held pressure for 3 weeks of high 90+ heat. It need some more now, but still works at highway speed.

Klaus
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1967 220 belonging to C.A. lives on

Klaus,

Aside from the evaporator leak, I'm wondering if a small fan on the compressor will improve Volvo's AC. You've said a time or two that the compressor will cycle off if it gets too hot. Will a fan or air duct or both keep the compressor from overheating? My '99 V70 lost the lower engine cover and I'm wondering if that is causing the compressor to run hot.

David

David, I'd certainly recommend getting a new air guide, especially in NC. IPD has some direct replacements that should work good.

I have to do the breadtag fix on my compressor but nearing the end of summer I will hold off. If I have to use the AC during the fall the chances are the compressor will not get as hot as it does in the summer and should not have the Electromagnet kickout.

From what I can gather, the compressor heats up because there is too little refrigerant. It should still be cold when leaving the evaporator and makes its way to the compressor. When there is not enough R134a in the system, it will be at outside temperator which then causes the compressor to get hot.

You need to be aware of 2 things. The clutch gets harder to engage when the compressor gets warm (because of the gap) and if there is a slow leak you need to add a 12oz can to make the system cold.

Not having the air guide on the bottom of the engine will actually keep the compressor cooler, but not help the condenser do its job.

If you haven't done the bread clip fix yet, now is the time. If the return pipe from the evap is not sweating like the pipe going to the firewall - after a 10 minute trip - add some R134a. The system does not work well at idle, so a road test is needed.

Klaus
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1967 220 belonging to C.A. lives on

I replaced the evaporator at around 150k. No further AC problems except having to remove a shim from the compressor clutch. 1998 V70 320k.

I can't answer your question about the evaporator, but I was thinking there might be a way to inspect your evap before you start tearing into it? Like maybe one of those inspection cameras like they use for drains or going through spark plug holes or whatever. You might be able to thread one of those cameras in there and have a look at how it looks before you take anything apart to see if that's really the problem or not.

If you are buddies with someone with an AC shop they might be able to help too - I /think/ I have heard that you can evacuate the system and then pressurize it with plain air and listen for leaks?? not sure about that though...
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1998 V70 AWD->FWD->AWD Turbo 215k+

In answer to your real question, the AC shops are supposed to pull a vacuum and make sure the vacuum holds for 45 minutes. I doubt that any shop is going to wait for that long, most leaks will show up sooner than that.

It reached 97F today, so I broke down and added a 12oz can. Black cars get too hot. The AC worked great, but after 20 minutes the compressor shut down. I didn't check the pressure, but the compressor shut down because it didn't cycle and over heated. The cabin was warm enough so the vent temp never even turned off the recycle vent.

My MB will freeze your socks off, but I don't like how the system works. The Volvo ECC is much better, too bad the AC is over engineered and delicate.

I still haven't found something to make a puller with. I am thinking about a piece of 1/4 inch copper tube, but that might be too soft.

Klaus
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Always willing to listen, just not able to take direction.

I unscrewed the cap for the schrader valve this morning and it was bubbling!!!

With other commitments, I managed to get to the parts store and get a new valve and puller. They don't fit!!! It says "fits most cars", but I guess Volvo is not most.

Now I need to find a puller and new valve somewhere else, on Monday...

Klaus
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Always willing to listen, just not able to take direction.

You are supposed to be able to see part of it if you remove the blower resistor and look through the hole. Just doing that is a pain for a lazy guy, the glove box has to come out to drop down the kick panel.

I guess I need to do another dye test. Check the accumulator bottle and hopefully the AC drain on the garage floor???? Clean off the schrader valve and wrap it with Saran wrap, see if it baloons up? Ha, ha.

Klaus
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Always willing to listen, just not able to take direction.

Klaus, if it leaked all the old 134 out, and, if you determine it is the schrader valve and replace it I would recommend that you have an evacuation done on the system after you service it. Nothing worse than dumping a few cans of freon in there just to have lackluster performance of the AC system due to "air" being in there.

I leared that the hard way back in college when I swapped a compressor on my old 740 :-/

I appreciate your advice, but the system is not 'empty'. My intention was to remove and replace the valve, if I can ever make a suitable puller. There should be minimal air going into the system. If I were to remove any piping, I would replace the accumulator and vacuum the system to get all of the humidity out.

I just stopped by an AC shop today: $150 to replace the $5 valve. What a pain.
Of course, they would not let me borrow a valve puller :>)

Klaus
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Always willing to listen, just not able to take direction.

I was just at Harbor Freight and they sell a boroscope with a small LED screen that it perfect for checking inside the dash. I am going to pull out the cabin filter and drop the gooseneck camera right down the hole to look for dye. I wish I had the balls to do a dash pull, but the thought of doing an airbag/steering wheel R&R scares the crap out of me.