Right so I got a few bottles of R134a at WallMart with a gauge and all. I followed the instructions and filled with 2x 12oz of refrigerant. It was cold outside about 36F, but the engine was runnign warm.

I could see from the guage that the compressors was cycling fast at too low a pressure. Adding the 2 cans of R134a made it all come together nicely with the low pressure end not dropping to below 23psi, the lower pressure cut out of the compressor. The cycle is now about 20-30 sec at idle.

All seemed well til I started looking on the net about recharging. There seem to be a lot of people that think it is a bad idea to top up, since you do not know how much is left and thus do not know the total system fill. Mind you these are all the specialists that seem to benefit from their "advice". Their general advice was to not touch it yourself and go to a shop instead, what sort of advice is that!

Now I am concerned I have overfilled the system, something I guess will be especially problematic when the temperature starts to rise. There is however a high pressure cut out switch in the system, which I assume protects the system from blowing up. But does that mean that it will now be inefficient since it will be cycling at high pressure in/out?

So my questions. Can I diagnose if I have overfilled the system by checking the HP switch? Assuming it cuts in, should I release some refrigerant till that does not happen and should it then be fine, or is not normal for the HP switch to kick in? And what is the influence on the weather, should I be using different pressures or does warming up the system make it indifferent to the weather.

What are the risks associated with overfilling the system, is it just going to be inefficient, or can something break?

Your answers would be much appriciated.

V70 1998 90kMiles

JS,
I just got back from autozone and charged my A/C with a can and a half of gas. My system was cycling on and off every few seconds and pressure was showing below 20PSI. With one can it was still cycling off every 15 seconds or so. Taking a pan of hot water and putting the second can in it let the gas enter the A/C system much faster. Then with a thermometer, with the A/C blowing full blast only through the center vent, and on recycle, I measured the air entering the cabin to be right under 40F degrees (anywhere around 40 is okay). The cycling of the compressor was now more like every 30 seconds or more at idle...this is about right. With the car running it shouldn't cycle much at all. Checked the pressure (with car running) and it was right where it's suppose to be at about 35PSI or so, so I stopped filling. The PSI's were the same with the car off. If you get over 45PSI then you may be over-charging but then again, my understanding is that the Volvo A/C system is of a higher pressure when charged correctly than what these cans let out so it's about impossible to over-charge (unless you get the cans hot...warm is good, but hot is not). Just thought I might give you some info on how I do my re-charge. Hope mine now holds thoughout the summer.
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1998 S70 T5 Emarald Green Metallic, 2004 V70 2.5T Ruby Red, Previous Owner of Black '94 850 Turbo Wagon. My cars have been running so well lately they've got me worried.

Hi MadeinJapan,

I can see you are a regular contributor to this forum. I appriciate your feedback, it makes me feel a lot better knowing that what I did was not out of the ordinary.

V70 is a sophisticated machine, compared to my own 92 240 (V70 is wifemobile). I am sure I will be picking up a lot of good advise from this board.

Many thanks again,

Jorn

You didn't hurt it. And the cans of r134a come with oil in them, so you don't have to worry about that either.
Checking the high side pressure is most difficult, there is no fitting for that.
Relax,
Klaus
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(V♂LV♂s 1975 164, 1995 854T, 1998 V70R)

I have found cans with or without PAG oil. If you have opened up the system you might have oil only in one part or another (like with a new evaporator). If so you can mix and match cans with or without to get somewhat near the right amount at the end. This was in a real auto parts store with counterpeople, not a Wal or K mart. You can also choose the viscosity of the oil.

Well I bought the car recently for the wife and it does not look like it has ever been opened. The refil I used was without oil. No signs of leakage, so I guess I will be allright.

Thanks,

Jorn

I would leave it alone. A 28 oz charge or so is allowed in warm climates. Did the fill you put in contain any PAG oil? If not you might be short of oil. I personally would not worry about this unless the system was opened up in the past (where you definitely lost oil). You can get small cans with 1oz of refrigerant in which aome oil is dissolved.

If you're cycling off and on at 20~30 seconds I would not worry about it...this is fairly normal, especially at the temperatures you mention. Drive it and see how it does in the warm. I would not touch the high pressure side. Leave that for professionals....dangerous! Actually, the recommended fill temp is 60F or more, so you filled at lower temp, but like you said, there is a pressure release if too much gas is in there, so there really isn't any worry. Besides, the pressure in the cans (from what I understand) is not enough to over-load the A/C system (unless you're using a big metal tank), so whatever the Volvo A/C system is willing to take in from the cans will be fine (from what I understand).

I have to fill mine too. Last spring I filled mine as temp was not changing with A/C on or off in the cabin. I thought my Evap was bad but it wasn't. I'm hoping that winter cold shrunk the "O" rings and I lost coolant again. May get lucky with a fill, but my Evap for sure may be gone this time, but I hope not.
--
1998 S70 T5 Emarald Green Metallic, 2004 V70 2.5T Ruby Red, Previous Owner of Black '94 850 Turbo Wagon. My cars have been running so well lately they've got me worried.