A/C Doesn't Work

[Kittamaru]

Well, for a year or so now, my A/C has not worked...

 

my mechanic said it was very low on refrigerant, and tried to top it off, but every time he did, he said the overpressure valve blew. My compressor spins up and engages, but only for a short while before stopping. I get maybe 10 seconds of cold air, then nothing.

 

I'm not even sure where to begin with this... any tips?

[5523Pathfinder]

Here is what I would do. Start your truck and turn on the A/C, let it cycle and start feeling the different hoses and lines for tempurature change. coming out the the evap, it shoudl be fairly cold all the way to the compressor. From the compressor, it should warm up, be shoudl have a temp drop on the other side of the condensor. Ive never heard of a overpressure valve. The is a pressure sensor that works if too much pressure detected or too little pressure. If you had the system serviced, find out how much refridgerant was put in. Also take a look at your sight glass on the fluid tank and see if there are any bubbles. If you notice a excessive amout of dirt collecting around any fittings, you may have a leak.

[Kittamaru]

I don't have a sight glass (least not that I can find), and my system was updated to the new specs a few years ago (new coolant and such). No leaks I can see or spot. I'll have to check the rest in the morn.

[5523Pathfinder]

So its been converted to R134a? The sytem still operates basicly the same. Just at different pressures. Check the lines and make sure nothing is unplugged or damaged. I say start with having the system recoverd to see exactly how much refridgerant is inside. IF its low, then you have a leak somewhere or the wrong amount was installed. Evacuating the system will tell you if the system is sealed. If not, you have a leak. If all ok, recharge with the correct amount.

[adamzan]

Could be the temp sensor for the compressor is not working right if it kicks off so fast.

[Kittamaru]

I have no idea how to recover the system 0o' Can you give someone who's NEVER played with the A/C at all a quick how to?

[adamzan]

You need to take to a shop that has the machine to do it.

[Kittamaru]

Ah... I don't believe my mechanic can do that (he told me he's not an A/C specialist and doesn't feel comfortable doing anything but basic maintenance on it) and the stealership would rape me for it, wouldn't it...

[nunya]

Pick up the phone, one of your local shops should have a recovery system, and be able to tell you how much to do it. (Not being smart about it, just didn't see it suggested)

[Kittamaru]

Well... problem is I'm already coming up almost $200 in the red so far this month (****** hours last two weeks resulted in a terrible paycheck) so I can't afford to have a shop do it unless they'd be willing to give me like, a month to pay it off... *sighs*

 

If anyone knows a good job in Eastern PA... let me know... please? I think I'm starting to annoy places by applying and re-applying everywhere within a 25 mile radius... ugh!

[adamzan]

If you can't afford it then roll down the windows. It's not even that hot this summer, which is almost over anyways. I've barely used mine.

[5523Pathfinder]

Yeah, to be enviormentaly friendly, you need to take it to a certified shop. YOu dont necessarily have to take it to the dealer, just someone who knows what they are doing. R134a is still damaging to the enviroment ans should be contained properly. All this stuff takes equipment, and isnt always cheap. Yep, search locally. I know quick lube places sometimes will have a certified A/C tech there. There are some shops that only do A/C work. As the old commericals went...."let your fingers do the walking!"

[blackspawn]

Well, for a year or so now, my A/C has not worked...

 

my mechanic said it was very low on refrigerant, and tried to top it off, but every time he did, he said the overpressure valve blew. My compressor spins up and engages, but only for a short while before stopping. I get maybe 10 seconds of cold air, then nothing.

 

I'm not even sure where to begin with this... any tips?

 

I'm having that exact problem that you're having when you put a can in, it comes out the over-pressure valve which is located on top of the compressor on the high side line. It looks like a screw on adapter or something. I've taking it off to see if it was stuck open but I didn't find anything maybe I need to push the inside of that valve harder to see if it is stuck open. I asked nissan part stores online but did not find that little piece. The only thing I found was the whole high line itself, that sucks!!!

[Kittamaru]

I've been using the windows Just kinda hoping I could get it fixed for next summer

 

My big thing atm, though, is I have higher priorities than my A/C - was hoping it'd be a quick do it yourself fix.

 

First on my list - my oil change, which I'm almost 200 miles overdue for... hopefully I made enough in tips this week to actually buy the oil and filter so I can do that 0o'

Then I need to get the body rust taken care of - I've stopped it spreading with regular treatments of rust prohibitors like naval jelly... but I want the holes fixed damnit, and I want them fixed right.

 

Once that's done, then I can worry about the A/C

 

*sighs* So much to do, and no money to do it with XD

[RedPath88]

I don't have a sight glass (least not that I can find), and my system was updated to the new specs a few years ago (new coolant and such). No leaks I can see or spot. I'll have to check the rest in the morn.

The sight glass is located in the Liquid Tank. Which is on the right hand side of the evaporator, forward of the radiator

 

[Tungsten]

Here is my 2c.

After weak A/C operation, I took it to a shop to flush and recharge the system. The A/C worked great until a bad smell came in from the vent duct and my A/C quit entirely. I'm thinking its a bad evaporator but might as well replace at least the high pressure line too. I have been putting this repair off for a year now because I barely use the A/C but now I'm pretty much broke after the timing belt change so its going to have to wait a little longer.

[5523Pathfinder]

Well this sheds a little light on the subject. Its possible(Possible, dont get carried away) that the shop you took it to may have done something wrong. Maybe they put the wrong refridgerant in the system. Maybe they didnt put enough oil in the system after evacuating and recharging, and burned up the compressor. Man, its hard to tell you what to do. I would (when youhave the dough) take it to a reputable shop that has a A/C machine that can detect what refridgerant is in the system before anything else is done. On the cheap, you could go to the A/C relay and jump the terminals and send power to the compressor and see if you start blowing cold. The bad smell indicates to me something may have leaked, possilby in the case, but also from the engine bay. Its free to poke around under the hood and see if anythings stands out as a leak or a break.

[Kittamaru]

Oh the compressor WORKS, and pressure builds up, and the system gets cold - but only for a few seconds, then the compressor kicks off an doens't come back on *shrugs*

 

I can't see any real leaks so I don't know if that's the case either.

 

Once I get a litle time to play around I'll see what i can see - if I get the cash to do so, I'll take her to a goo dmechanic

[Tungsten]

I found the leaks on mine, just no money or time to fix them. lol

 

1. High pressure port from A/C compressor

2. Evaporator

 

Probably have to replace all the seals along with the receiver drier of course.

 

Then recharge and enjoy!

 

This is my case so I hope it helps you.

[magregor]

This "no money" thing must be contagious!!! Gotta find a cure soon too!