Nissan Repair: 95 Nissian Quest, nissan cars, nissian

Question
My air cools when it is under 80 degrees outside but in AZ that isn't often.  I don't want to buy a new car for 2 years. I told the mechanic that the problem was that I drove in a 5 mile radius and hardly ever drove on the freeway. My car just won't cool in the Arizona heat but it would when it was under 80 degrees outside. So, they told me the compressor needed to be replaced and they had added freon last week when they replaced the timing belt.

So, I just had the compressor replaced today.  I pick up my car drove a steady 5 miles and it never cooled.  The blower worked better but it never cooled.  They suggest I drive it further and give it a chance.  I explained my driving pattern before and after the repair. I paid out 900 for a new compressor and it isn't blowing cold air.

How can I describe the problem to my mechanic to get the air to blow colder?  What can I assist he check now that the compressor is replaced? They added freon last week. Is it normal to add freon when the compressor is replaced?

Answer
Kim,

Have the shop check the system pressures to make sure the high and low side are where they are supposed to be.  Something like 37 on the low and 270 on the high side.  These are ballpark on my part but they are close.  If the high side never gets high and the low side does not get that low then the expansion valve is stuck.  This is probably the case and what causes it is the compressor going out.  You see, when the compressor dies it lets ground up metal circulate through the system and then it messes up the expansion valve.  This is all a guess on my part since I have experience working on Nissan cars and that is the most probable  thing.  Other causes could be the cooling fans not both coming on when the airconditioner is on.  Remember that you are running R-134 and it is not as efficient as the old R-12 so it takes longer to get the system to cool down.  Other things you can do to get the system to cool better is to tint the windows and make sure there are no air leaks.  Also, you can insulate the air box under the dash to aid in quicker cooling.  Other tricks are to spray the radiator down with the water hose after you start the car.  The cold water will aid in getting the airconditioning to cool.  I live in Las Vegas and I know what you are talking about.  I pay $35 a month for covered parking since it gets so hot.  I live seven miles from home and it just starts to get cool by the time I get home...