Last Friday, I had the rotted accumulator replaced on our red 1998 S70 at a Volvo shop. This was brought to my attention about 3 years ago. The very next day I drove the car 1-hour to my destination and everything was cool (it was close to 90-degrees outside). On my way home I noticed that the compressor was cycling more frequently. 30-minutes into the trip, the compressor was cycling about every 3 seconds and the AC was blowing hot air. The AC, by the way, was blowing cold prior to bringing the car in the shop for repair.

Some background: About 4 years ago I was told by the tech that the evaporator was leaking. I had a very slow leak and so, since then, I have been using at least 1 or 2 cans of R-134a refrigerant (from Walmart) and the AC worked fine for about a year.

With the accumulator having been replaced, is it possible that the deterioration on the evaporator has been accelerated so suddenly? I am hoping that there is another leak somewhere else caused by the installation of the accumulator. The sudden lose of refrigerant doesn't seem to have been caused by a leaking evaporator. I am trying to avoid having the evaporator replaced as I am aware of the work (and therefore expense) involved. I can live by 1 or 2 cans of R-134a every year.

Any observations, suggestions, or comments? Please?

Thanks in advance!
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Brian M. - 1998 S70GLT, 1998 S70 GTA

Thanks to all who replied, especially to Klaus for his thoughts.

Here's the UPDATE:
Well we decided to have the evaporator done since it was long overdue. We just brought the car home and everything seemed very good. The dash was tight and no squeaks, rattles, or scratches. All electronics (lights, stereo, glovebox CD changer, etc) seems to work fine. I checked the A/C lines from the firewall to the accumulator and nothing seemed to have been replaced -- they are all the original ones. It was an expensive repair. My wife and I were a little hesitant at first but everything worked fine. We now have that 'new car' scent coming through the vents. ;-)

The shop showed me the old evaporator with dye covering almost a fourth of it. He said that he blew compressed air in it and observed that it was leaking bad. He explained that originally (with leaking evaporator and rotted accumulator) the pressure in the A/C system was low. When they vacated the system, installed a new accumulator, and then filled the system with refrigerant, the greater pressure caused the leaking evaporator to give up sooner.
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Brian M. - 1998 S70GLT, 1998 S70 GTA

I have found that on these cars the rule of thumb is ,when the accumulator goes, the evaporator isn't far behind. I guess they both deteriorate at the same rate.
eEuroparts.com sells them as a kit with all the new seals. I don't know if it is cheaper that way but it does send a message.
I just wish the dash and other areas would be more easily removed to provide access to those hard to reach areas.
RK, 96 850 wagon. 98 V70XC FWD

It's not the location of the evaporator, rather the single piece for the cabin airflow. Designers could have left a way to remove a few panels to gain access, similar to the heater core.

Klaus
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The more I learn, the more I forget. So why learn?

UPDATE:
The Volvo shop used a 'sniffer' to try and locate for leaks. They determined that the new accumulator was faulty at the connections, so they replaced it with a new one. They took the car for a test drive and everything seemed fine. I arrived half an hour later to pick up the car and I immediately tried the A/C and it was blowing 'warm' air! There was an immediate lose of refrigerant and the compressor was cycling again every 2-4 seconds.

They want me to leave the car again tomorrow and they will be checking with the black light. Any ideas?
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Brian M. - 1998 S70GLT, 1998 S70 GTA

The mechanic who replaced the accumulator probably FU'ed. Very hard to prove.

Klaus
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The more I learn, the more I forget. So why learn?

Hi Klaus,

The car is in for a 3rd time now and they said that they checked everywhere for leaks. They said they found quite a bit of refrigerant inside the car and so are assuming it to be the evaporator. They are assuming that when they charged the system with refrigerant the first time they replaced the accumulator, the evaporator was affected by the pressure. Is this true or possible?

As noted on my original post, I was told about 4 years ago, that the evaporator had a slow leak and since then, I had been putting refrigerant (1 or 2 cans a year) and the A/C always worked. Is it possible that the evaporator could have given up when they charged the system with refrigerant? If it were true, I regret having the rotted accumulator replaced since the A/C worked prior to the 'repair'.

One of the owners of the shop asked if I could come down so he could try to explain things. I haven't heard anything bad about the indie shop, only good things from different people. I am going down there now and see what he has to say.
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Brian M. - 1998 S70GLT, 1998 S70 GTA

All 850 evaporators leak eventually. We all know yours did, you just put it off. It is possible, that the evap gave up the ghost during the procedure, but not likely.
What bothers me is that the first time, they found a leak at the cannister. I would suspect that part of the system is still leaking and contributing to the problem. A dye test is needed, and insist on it.
The evap can be seen, a little of it, and a black light used to check for gross leakage, under the dash.

Klaus
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The more I learn, the more I forget. So why learn?

Klaus, sorry for the delayed reply as we just returned from vacation.

The volvo tech (who also is one of the owners of the shop) said that it was the evaporator. Also, he showed me a tube coming from the firewall that goes through the ECU housing and that he discovered refrigerant coming out from it. This in turn was filling the area with freon -- the area where the accumulator was connected, and which was setting off the sniffer. I assume the tube coming out from the firewall to the ECU housing is connected to the evaporator, too?

They said they will charge for the evaporator repair minus the cost of the accumulator.

What are your thoughts?
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Brian M. - 1998 S70GLT, 1998 S70 GTA

I just have a hard time with that. The evaporator is behind the firewall. The 2 tubes that go to the evap, one in and the other one out, do go next to the ECU box, but where they go through the firewall is a seal. If the evap is leaking, the gas will stay inside of the cabin and not get to the engine bay.

If the mechanic twisted the line while removing the accumulator, he could have caused a leak at the line. Those fittings are quite stubborn to get off and the line pressure is quite high. BTW, the line goes under the ECU, not through the box - the condensation would kill the ECU.

Replacing the evaporator is a long job and is not cheap. I would get a second opinion.

Klaus
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The more I learn, the more I forget. So why learn?

Thank you for your insight, Klaus. I will try to get a 2nd opinion.

I do want to understand more of this. When I went to their shop, the tech had pulled off the plastic tube from the ECU housing (the one that connects to the radiator housing?) and said that air was coming out from the ECU housing. He said the sniffer picked up refrigerant coming out from it. Not knowing a lot about the A/C system on our car, how is this possible?

P.S. I am not sure if it is worth mentioning but the one who diagnosed that the evaporator was leaking was at a Volvo dealership 4 years ago where we used to have our cars serviced for years. We started having our cars serviced at this Volvo indie shop 2 years ago and I never mentioned to them about the leaking evaporator.

The reason why my wife and I are thinking of having the evaporator replaced anyways was because we have been putting it off for years. If the tech did make a mistake, I believe they will fix any leaks that show up when they replace the evaporator -- as long as they don't charge extra for it!
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Brian M. - 1998 S70GLT, 1998 S70 GTA

That plastic tube that goes to the ECU box is for fresh air, it helps keep the ECU cool. Don't want to fry that baby!! The air only goes through the box when driving down the road, no fans, no ac duct, etc. Any r143a found in the box is the result of a leak around the accum bottle.

As you already know, the accumulator is fairly inexpensive. When it fills up with pag oil from constant filling, by you, it robs the amount of r134a the system should contain.

Your Indie broke it, he should fix it. Any yellow dye test will confirm where it is leaking.

Klaus
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The more I learn, the more I forget. So why learn?

The tube goes to the ECU for cooling, but the plastic ECU box has another tube on its backside that goes through the firewall and ends up between the blower suction and the evaporator. It seems to use the blower motor to help get ECU cooling airflow. It is plausable an evaporoaor leak could give you a reading at the plastic tube you mentioned.

98' V70 5-spd 285k.