92 sc300 with 1jzgte a/c issue
 

alrighty, recently (start of summer) my a/c has been barely working. if i put my hand up to the vent its defiantly colder then the outside but maybe only 10 degrees IF that. also, the fan doesnt blow all to hard when its on recycle with face/feet on.

i have a full setup to install freon and i had my uncle (whos trained in hvac) to help me over the phone to do it. i added the freon step by step, and it started to get a little better but, theres ALOT of freon already in the system so i dont see why it wont work. when i say alot, i think its around 58psi. i heard its to much, but when i started adding it, it was around 20psi. i tried stopping intermittently and it only started getting cool around 55psi.

ANOTHER thing to point out, is that at idle/stop the a/c dyes WAYYY down to the same temperature as the outside, its as if only higher rpm's made the a/c work. which makes me think it has something to do with the compressor clutch

so:

1. add more freon
2. vacuum freon/refill
3. replace condenser
4. replace compressor
5. check relays/wiring

top; 10char

Well bryan it would be beneficial to watch both side of the system. ie gauge readings for the low which you are quoting in your first post, and also for the high side. this will give you a better understanding of what's going on in the system.

Your idle problem could be a couple of things, such as a fan issue or compressor not pumping enough at idle like you had suggested earlier.

I know this post is a bit old so i'm assuming you've remedied the issue. but if you want some more help let me know.

hope this helps.

thanks, unfortunently i havnt remedied the issue yet. i think i have ice in the system. OR my in cabin air filter is clogged... cuz it bearly throws air out anyway. also, i dont have a fan on my condenser. is that normal??

ice? like frozen water? or like a can of auto store bought refrigerant? cabin filter could cause a volume problem, if you had one. I don not believe that you do though. As far as the condenser fan goes the 300's only have a fan clutch. that is belt driven. the 400 does have an electric fan.

i see, this answers alot of questions haha.

as for ice, yes.. as in air that got into the a/c lines when refilling, they collected moisture and turned to ice. i think this is the problem.. but i really dont know.

possible but only if the compressor and rest of the system is working properly. The evaporator should not get could enough to freeze up. the only reason it will is if there is a "foreign" obstruction in that area if the system, or if the expansion valve is stuck shut or nearly shut. this would cause too much of a back up of refrigerant, thus causing more of a pressure differential and more of a drastic temperature changing, thus freezing it over. this will only happen when it's running though.

i see. i also noticed that the psi is like 55lbs.. but it was below 20 when we started. and around 55s it started to actually cool.

Too much freon and it won't cool, too little and it won't cool. You should evacuate all R134a, then refill the proper amount.

Most a/c shops don't charge but $60-75 to drain/refill and troubleshoot your system to find out what may be wrong

He's right expansion valve freezes up and you have no cold air...I just replaced one actually in the mkiv.

so dump it, and refill to what amount. and if that doesnt work, replace the valve?

No, evacuate it then charge it with the proper charge amount, (this would be with a proper a/c machine). that would be the "correct" way to do it. You can charge it manually through the low side, like you're doing. But you're skipping a crucial step that way, i assume. The system needs to be pulled into a vacuum for at least 15 mins. More like 20 to 30 mins. this will get rid of noncondensibles, like air.

Although if it's a 92........wait. what r u charging it with? 134? has to be. was it ever converted correctly?

yeah 134, i believe it was converted but, im not the original owner. the car was brought from florida 2 years ago, so i can only assume that since its been in florida that the a/c was swapped over (it had about 5 different layers of different tint when my guy was taking the remainder off so he could but a new layer on)

what i dont get is why it only works when its already cool outside. think its the condensor gone bad? bc thats what im thinking. like itll actually get down to low high 60s if its already 75ish outside. but if its about 90-100 itll only get down to maybe 85-88

a/c problem
 

Im having the same problem with my 96 sc300, I empied the system using an a/c vacuum then refill with one can of 134 and small can of oil for 134 system, im just not sure if thats the correct amount because im having the same problem that Bryan does.

Where is the expansion valve located?

i was thinking about hooking up a honda civic electric fan to the condensor so at lower speeds itll still have air pass through it. i also noticed that i dont have any water droplets coming from the car?

It's in the HVAC box. Behind the dash/glovebox area. dash comes out to get at it.
that would be beneficial once your system is working properly and still isn't cooling to your liking. Still need to install a proper set of a/c gauges to properly diag what's going on. you really need to see what the high side and the low side are doing. at both idle and at performance testing rpm's. If you're running 134a in a r12 system the correct amount of 134 for that system is 1.76lbs.

Not sure what the charge amount for an actual 134 newer system is, (just did another members a/c in her sc today).