I need help diagnose AC issue with my 99 V70. It starts cool and eventually stop blowing cold air after about 20 minutes of driving. I am going to check the pressure this weekend.
Is there a low pressure and high pressure ports in V70?
Where should I plug pressure gauge to check the pressure?
Has anyone come across same symptoms before? and what was the cul[rit.
Thank
SS

 

That sounds like the common compressor issue where the clutch is failing. Check out this post for more information: https://volvoforums.com/m_34431/tm.htm

 

Is the fan still blowing? If it isn't it could be the evaperator is frosting up and then you hage a expansion valve problem, some signs of this is right before it stops blowing cold airit looks like fog comming out your a/c vents. Try turning the heat on and this will melt the frost away and let you know if the evap is frosting over. If the fan is blowing good the freon could be low or the clutch is worn. I'm not sure for the Volvos but usually the low is 30-50psi and high is 150-200psi. I had the same problem on a Lear jet and it was the expansion valve. I know Lears and Volvos are different but a/c systems are mostley the same on aircraft.

 

Actually, yeah, I guess clarification is needed: do you mean a) there's air blowing out but it's no longer cold or b) there's cold air but it's not blowing out (might feel like it's trickling out)?

I've had both symptoms in my 99 V70 and had to replace the compressor for the first problem (a) and the blower motor and blower motor resistor for the second (b). I'm still leaning toward the first problem because of the <30 minutes of cold air before failing. That sounds like the compressor clutch failure (which seems very common on these cars).