Ok guys, I have done some searching and havent really found the answers I am looking for. I have a 97 4runner SR5. I have noticed that my ac doesnt get verry cold. I was thinking it might just need to be re charged, but I went to put some r134 in it I found something odd.. I hooked up the fitting turned on my truck, turned on the ac of max and checked the meter.. It is in the yellow touching the red. I think is at about 65 psi.. I was told this is not right and it should be in the green, way lower. My question is should I, and can I just let pressure out of that fitting? Will that even help? Or is there something else I should look for? Thanks allot guys.

 

I've let pressure out of the low side. Although, I'm pretty sure letting that stuff out into the atmosphere is illegal. I'm no a/c expert, but too much pressure in the low side would lead me to believe that I had a malfunctioning expansion valve.

 

what is the expansion valve? where is it? can i check it?

 

The expansion valve is located "in the system".

It act's as a cushion so when pressure builds up [expansion] the system won't blow an "o-ring" or another component in the A.C. system.

You'd be better of taking it to a qualified A.C. tech. rather then trying to repair it at home.

If the expansion valve is bad, it will have to be replaced, then the system will have to be sucked down [vacuum] and recharged with 134 and appropiate refrigerant oil.

 

You bet just went through this with my wifes Jeep grand cherokee. It was cool, but not cold. I tried the easy bottle of do it yourself stuff, with the built in guage, and strangely enough there wasnt enough refrigerant to make the compressor cycle like it should, It has a pressure switch that senses low refrigerant and keeps the compressor from burning up so obviously it was low on refrig. however the guage said it was in the red too. Well turns out after taking to the shop that air in the system will do that and air doesnt cool, and you cant force more refrig on top of that. So yeah in short your going to have to take it somewhere and have them vac it out and then recharge it. Should work like a charm. Cost me 90.00 and now the air blows 42 degrees again, brrrr. Still dont think its as cold as my 4Runner though.

Matt

 

if you got those r134a bottle w/ guage, the reading could be an error.

my neighbor used one of those and it was at green area of the guage and he stopped pumpin in but his ac was NOT cold. he took it to a mech and the system was low of 12oz.

typical expansion valve. located bt high side(from compressor to cabin) and evap core(in the cabin). very important part of refrigeration system.

 

Ditto....this was what I told him in chat last night as well.
I don't suggest people do their own AC service since the costs can be very high if you break something.

 

Thanks for all the help guys, I have an oppointment monday to have the ac looked at. I have a couple friends that work there so i hope I dont get yanked.. Anyway thanks for the great advice. Id rather have it fixed right than ruin something worse..

 

I just had the same problem with my wife's 4runner. On the way to S. Padre Island the a/c seemed to be getting warmer and warmer. So I pulled over to an Autozone and bought a gauge to test the freon level. Sure enough it was low. So I added one can and it filled it to the proper level. I am positive I even heard the compressor engage but the a/c started blowing completely hot. When I tried it again the compressor seems to engage intermittently. When it egages it makes a funny noise. Maybe it's the belt but it seems to be coming from in the cabin. What else can the problem be? Thanks.

 

AC kits .com They have a forum that will answer just about anything on airconditioning.They also sell equipment and kits to convert over to 134a the right way!

 

I found out it was the high pressure switch. I was told that once that was replaced that the dryer and expansion valve would also have to be replaced and the system would have to be vacuumed and charged. Total cost including tax $489.