Hello
My 95 volvo 850 turbo sedan ac is blowing hot air . It had no freon in the system so i bought the ac kit at advance i checked system n there was nothing in there i added about half a can and got to 50 psi when clutch started to engage and the. Couple seconds later disengaged. (Was told its called short cycling) does that for about five minutes and when the clutch dies enage the pressure reading drops down to about 25 psi right very low reading in the green part of gauge. Does this mean i should add more freon ? Or is there another problem somewhere else ?
I added some more freon during the short cycling also and now it reads in the red of the gauge thats when the clutch isnt enagage. When it does enagge it drops down to 25 psi.
Also after 5 minutes of short cycling it stops and wont enagage again . Please help dont know what to do ! I dont want to over charge and i have very little money to fix ac

 

When the clutch disengages the high side and low side will equalize. The pressure will often be off the gauge and that's OK.

You only care about the PSI reading while the clutch is engaged and it's running. Average day you want to be about 45-50 PSI. Should be real close to the red area on the gauge. You need to add more.

 

+1, Add more.

 

Ok so how much more do you think.i should add ? until the ac starts to engage again ? And then let it run for a few minutes to see what happens ? Im at the begining of the red now i.can go.further into red .
Thanks so much !

 

Also how would one know when to stop adding freon ? Label says to stop when in red when the clutch is engaged but what if it doesnt fully engage thu ? Sorry im.new to this first time recharging a ac system actually just want to make sure i do it right dont want anything to happen to my car or me .
And how long shoulf i wait for the ac to.kick on and stay on after adding freon if it starts short cycling again ?

Thanks so much !!

 

What size can did you get?
The system holds 1.63 Lb.

 

It usually will take a 12 oz can and a half. So, if you got a tall can, get a small can and start to add as directed. The thing about it is I think it's impossible to "over pressurize" it. So rotate the can as the directions say and the clutch will kick in and stay in. Then watch the pressure and stop when it's just over 45 psi.

After you service it see how long it takes before it needs serviced again. Mine leaks down in about 4 or 5 months, loses a can. The other 850 I had would lose it in 3-1/2 weeks so I replaced the evaporator. Most of it was leaking from there. A evaporator replacement is a job that you DO NOT want to do.

Also, don't waste your money on stop leak freon. It's ok to get the freon with the dye to find out where it's leaking from but the stop leak only helps seals in the joints which are rarely the problem in cars.

 

You should stop at 55 psi no matter what the clutch is doing. At 55psi you are most likely slightly overcharged. Even at 40 psi you should have enough freon in the system for the system to operate normally. You may have an additional problem to being low on freon. You might have a restricted orfice tube and you're building too much pressure on the high side and shutting down from that. This is where having gauges on both sides of the system become necessary to diagnose the problem. You might be at the point where you'll need to bring it in to have someone check it out further or if you know someone who has a manifold gauge you can borrow or who will check it for you.

 

I bought the tall can and only put about.maybe half in amd the gauge reads in the red when the clutch is not enagaged. But when it does enagage it goes down to 25 psi right in the begining of the green im going to add some more now and see what happens.

 

Don't worry about the pressure when the clutch disengages. Bring the pressure up to 45 psi or so when it's running and you'll be OK.