Hi everyone,

Iīm new here and hope someone can shed some light on the problem I am encountering. I haver searched the net and none of the problem discriptions I can find match what I have going on with my 1997 V70 :-(
^
So, I got my AC regased about 7 months ago, all good. Winter came and I didnīt use the AC until about a month ago. It didnīt work. I thought it may have a leak, thatīs what my car electrician told me. He said the AC condenser wich lies deep within the dash likes to become leaky on these models. So befor I invest about 2000$ into getting it replaced (without knowing it is really the cause) I thought putting some "super seal" (AC system sealer bought from ebay) would fix my problem. So I went round to my mechanic and wanted to put the sealand into the system and then get it regased right away. The mechanic plugged his refil station into my AC system and told me it was full to the brim with 134a and he thinks I have a different problem.
He did a quick trouble shooting with his electrical fault finder. He checked all fuses (wich were all good) and then the relay for the AC compressor. He pulled the relay out and made me switch the AC on and off. Strangly the little green control lamp sort of worked and then didnīt work and there was some kind of delay after pressing the button on the dasch. It sometimes didnīt even come on at all and then once it came one (with a delay) it didnīt turn off after pressing the button. However, he short circuted the AC relay and the AC compressor snapped on right away, cold air blowing from the vents within seconds. Wow I thought, a darn 5$ relay, thatīs all! Well, it wasnīt.
I got home and repeated what the mechanic had done. Cold air came from the vents and I thought Iīd rev the engine to really get some cool air going. Having the AC compressor short circuted I reved the engine to about 4000RPM. Thatīs when I noticed a hissing noise (like from a pressure cooker) that became louder and louder. I also noticed white smoke coming from the engine bay, right where the radiator is, just under/in front of the air intake manifold. Of course I stopped the engine and the hissing and smoke stopped soon after. I could see that the pipes going to the AC compressor were now covered in fresh oil. I donīt know what 134a looks like when you spray it around the engine bay but I guess that oily stuff was 134a :-(
I also noticed that the AC compressor was running hard, the engine reves dropping quite a bit after engaging the compressor by short circuting.
What I did find out is that when I push the button on the dash (the AC button), there is now current on contact 1 of the AC compressor relay. With other words, something else is not engaging that relay and I donīt have a clue what it could be as I donīt really know how tha AC in a car works. I am just thinking the climate control unit might be faulty and because of that, it is not engaging the AC compressor relay to avoid exactly what I encountered.
So, have I now wrecked my AC completely? Are there some kind of valves that need to be opened before or whilst the compressor engages for the system to be able to circulate? I got the feeling the compressor was pushing against something and when I reved the engine the pressure got to high and blew off somewhere.
Hope this discription makes sense.

Any ideas?

Thanks heaps!

 

Hi everyone,

Just wondering if anyone has a hint for me, Iīm really puzzled with this situation.
Any idea is greatly appreciated!

Thanks again and have a happy new year.

Cheers

 

if i remember there is a pressure relief valve on the back of the compressor. the clutches were known to go bad on these. you would have power to the compressor but it wouldn't engage. if it was over charged then the valve could have popped. i would get it charged by a good shop that will evac the system, pull a vacuum and charge it with a machine that weigh's the amount going in. then try it again. good luck.

 

You likely have a bad clutch assy.

 

i forgot, the new replacement compressors don't have that relief valve anymore.

 

Hi everyone and thanks for your input. I have not gone down the path of getting the car checked out because I fear the cost for fault finding will outgrow the value of the whole car ;-(
Tony, I am not sure if it is the clutch. When I short circuit the AC compressor relay it snaps in right away and works fine. It does however make the impression as if it is running against something, it's not running freely, sorry, that's the best way for me to describe it.
Something is not open in the system so the compressor is building up huge pressure and when I give it the pedal something gives way because the pressure increases through reving the engine.
Could it be the climate control unit itself? Does the CCU actually control more then just sending power to the AC compressor relay Shen I hit the AC button on the dash?

Any ideas for DIY are greatly appreciated, it's hot here I'm Australia at the moment ;-)

Cheers everyone

 

i would recommend having someone with the propper charging station evac and charge it with the right amount then go from there.

 

I had a 960 do the same thing but the cooling fan relay wasn't letting the fan run, thus, the compressor engaged but slipped from high pressure.

 

very good point. if the fan doesn't come on w/ the a/c then the condenser doesn't cool and the pressures go sky high and the relief valve would reach it's blow off point and release freon.