92 Sc400 - Air Conditioning Not Very Cold

[AppleJack]

Advanced apologies if I missed an existing post - but I search for hours and could not find anything.

My 92SC400 usually blows ice cold air. I've kept it in good use activating the AC every week for a short while even in the winter. Now, when at IDLE and A/C compressor off - the engine sounds normal. When I engage the compressor, there is a sqeak or low tone whine from the area. I've loosened the tensioner and spun the compressor pulley/bearing and it's ok as expected. I've also turned the compressor and am not sure how hard it should be. I can turn it with one hand but only about 90 degrees max since there is some stiffness to it. If feels a little spongy like it's compressing something and I hope this is a sign all is ok with the compressor.

I've replaced the idler and tensioner pulleys a few years ago and the sound is not coming from them. Is it possible the added resistance is enough to make the belt noisy somewhere else. The belt looks ok - but probably has 100, 000 km (60,000miles) on it.

Any thoughts or ideas how to trouble shoot this further? The concerning thing is that it used blow very cold air - but now takes some time to get to just a comfortable temperature....

thank you,

[AppleJack]

Well, I've changed the serpentine belt and no change.

* Compressor still comes on.

* No error codes shown

One big thing I notice and forgot to mention. When I activate the AC button, there is a soft hissing sound from the center ducts. It only lasts for about 5 seconds before fading away. I'm not sure what this could be?

Any ideas? please help - summer is here and I am frying...

thanks

[Ratatat]

the hissing is from your expansion valve, normally that shouldnt be a prob. (expansion valves have been know to wear out in general, but rare.) you just might need a small amount of freon in your system. There might be enough to get the system running, but not enough to get the pressure up to snuff for the expansion valve to work, this is the item that helps cause the heat absorbsion from your car to give you cold air. It causes freon to go from a liquid to a gaseous state, in this state is can absorb heat.

[AppleJack]

Interesting. Well, I did add 1 full can (14 oz) of refrigerant and the hissing is gone and the cold air is back. Now I'm just waiting to see how long it lasts. 1 week and still holding.

I was advised the dark dusty area around my condenser connection might be due to a slowly leaking oring. Is anyone familiar with changing the oring seal in the area. Its in bottom right area in front of the radiator. If it's not a big deal I may do it myself or pay $50 to have it done.

thanks

[eatingupblacktop]

Interesting. Well, I did add 1 full can (14 oz) of refrigerant and the hissing is gone and the cold air is back. Now I'm just waiting to see how long it lasts. 1 week and still holding.

I was advised the dark dusty area around my condenser connection might be due to a slowly leaking oring. Is anyone familiar with changing the oring seal in the area. Its in bottom right area in front of the radiator. If it's not a big deal I may do it myself or pay $50 to have it done.

thanks

Clean it off, then check it regularly.

[eatingupblacktop]

Next time you top off the refrigerant, have some dye added to make it easier to trace any leaks.

[Ratatat]

also see if the connection just needs to be snugged up a bit. There is refrigerant that has dye in it also, uv type comes to mine, just use a black lite to see it.

[jbarhorst2]

Be careful about adding only freon to a slow leak. I did that for a while to mine several years ago and toasted the compressor. As the freon leaks out you are also losing oil. Once enough of the oil is gone, there is not enough to properly lubricate the system during use.

My advice, have the cheap problem taken care of before you get a bigger one.

Tom

[DaveMcKenz]

Apple J,

Did you add r12 or was your car converted to r134? What were your low side service port pressures? Some of the consumer (r134) products contain oil and leak sealants that may be helpful to you.

Good luck

[AppleJack]

Ok, here is what has played out for me. I had the condenser seal replaced and the area cleaned up. I lucked out and acquired 1 full can of r12 with the dye and the lubricant in it. The only problem is that I did not shake the can before use and I probably only got a little bit of the oil and dye into the system. This may be a good thing since the can indicated it had enough oil to charge the full system and if filling an empty system that all subsequent cans should be only r12.

It's been 3 or 4 days - and so far so good ....