AC help!! - Zilvia.net Forums | Nissan 240SX (Silvia) and Z (Fairlady) Car Forum

bees · 06-05-2007, 03:10 AM

i have a 95 s14 and the ac starts out cool but then begins to warm up. after a couple minutes of warm air, i can hear the ac compressor (idle changes) go at it and then the air is cool again. it goes through this cycle in repetition and i wanna know if i can fix this problem? ive tried adding a bottle of R-134a freon through the low ac line (the one that sits lower in the engine bay next to the exhaust manifold) but nothing has changed. is this normal? how do i get the compressor to run continually and blow cool air? dont know how much is covered here on the s14's ac system, but i did search. please help! thanks!

G-spec · 06-05-2007, 06:53 AM

the compressor has to cycle like that or it'll blow the lines apart...there's a high pressure switch the dictates when to lock the compressors clutch and when to release. If the difference is that apparent when the compressors not running then your system may still be low on refridgerent.....OR could actually to over full, condensor could be shot, or the dryer, its hard to diagnose AC problems without being there with tools in hand.....best best would be to take it to a shop with a set of AC gauges and see what they say.

contranication · 06-05-2007, 09:14 AM

From what I get, I think you are saying that the compressor cycles on and off right?

This will most likely happen when your low on refrigerant, which could be due to a leak or you haven't filled it in a while.

What you need to do is hook up a gage to the low side and it should read about 35-40 psi with the compressor running. If your too high then let some out, yes by pressing the valve stem thing, but don't breathe it. If your low then add till you get to this psi. To add or remove you want the a/c off.

If your system doesnt work right after this, then you need further diagnosing.

Hope this helps

projectRDM · 06-05-2007, 09:17 AM

No it cycles on and off to maintain pressure, that's completely normal.

contranication · 06-05-2007, 01:28 PM

Well no shit it cycles to maintain pressure.

but if it blows warm air then cycles on and off he is mostly likely low on freon or he has a big leak.

The only reason why he blows hot air in between cycling is due to improper/ insufficient flow of freon otherwise pressure would remain constant in between compressor cycles and he would not have hot air blowing.

Thats why he needs to check his pressure as I am sure you already know

projectRDM · 06-05-2007, 09:51 PM

Quote:

Originally Posted by contranication

From what I get, I think you are saying that the compressor cycles on and off right?

This will most likely happen when your low on refrigerant,

Your exact words.

I'm just reading what you wrote, which says that it's low on refrigerant because it's cycling on and off. That is incorrect.

jsuh s14 · 06-05-2007, 11:14 PM

yo.. i see that your located in socal.
ill refer you to a good place for ac.. did my whole custom setup.

Gardena AC & Radiator.
great guy.. good prices, and fast/efficent work

its right next door to the sr20 store.. if youve ever heard of it.

look him up and call him.. great service

bees · 06-20-2007, 02:50 AM

thanks jsun_s14, but i wanna c if i can DIY first.

so i tried using my ac again. i used it today and it seems to work fine, but only when the vehicle is moving. once at a stop (vehicle still running), the car goes into that cycle again. any suggestions? leak maybe?

06-05-2007, 03:10 AM	#1
bees Zilvia Member Join Date: Oct 2006 Location: socal Posts: 225 Trader Rating: (8) Feedback Score: 8 reviews	AC help!! i have a 95 s14 and the ac starts out cool but then begins to warm up. after a couple minutes of warm air, i can hear the ac compressor (idle changes) go at it and then the air is cool again. it goes through this cycle in repetition and i wanna know if i can fix this problem? ive tried adding a bottle of R-134a freon through the low ac line (the one that sits lower in the engine bay next to the exhaust manifold) but nothing has changed. is this normal? how do i get the compressor to run continually and blow cool air? dont know how much is covered here on the s14's ac system, but i did search. please help! thanks!

06-05-2007, 06:53 AM	#2
G-spec Leaky Injector Join Date: May 2007 Location: Rock Hill, SC Age: 47 Posts: 146 Trader Rating: (0) Feedback Score: 0 reviews	the compressor has to cycle like that or it'll blow the lines apart...there's a high pressure switch the dictates when to lock the compressors clutch and when to release. If the difference is that apparent when the compressors not running then your system may still be low on refridgerent.....OR could actually to over full, condensor could be shot, or the dryer, its hard to diagnose AC problems without being there with tools in hand.....best best would be to take it to a shop with a set of AC gauges and see what they say. __________________ GT3076r-boosted blacktop sr20det, s13 coupe Function over Form...

06-05-2007, 09:17 AM	#4
projectRDM Post Whore! Join Date: Dec 2002 Location: Atlanta Age: 51 Posts: 13,812 Trader Rating: (12) Feedback Score: 12 reviews	No it cycles on and off to maintain pressure, that's completely normal. __________________ FORMERLY R240NA Learn what's really going on and protect your assets now before they're gone forever: www.paypalsucks.com

06-05-2007, 09:14 AM	#3
contranication Zilvia Member Join Date: Jun 2004 Location: West palm Posts: 165 Trader Rating: (0) Feedback Score: 0 reviews	From what I get, I think you are saying that the compressor cycles on and off right? This will most likely happen when your low on refrigerant, which could be due to a leak or you haven't filled it in a while. What you need to do is hook up a gage to the low side and it should read about 35-40 psi with the compressor running. If your too high then let some out, yes by pressing the valve stem thing, but don't breathe it. If your low then add till you get to this psi. To add or remove you want the a/c off. If your system doesnt work right after this, then you need further diagnosing. Hope this helps

06-05-2007, 01:28 PM	#5
contranication Zilvia Member Join Date: Jun 2004 Location: West palm Posts: 165 Trader Rating: (0) Feedback Score: 0 reviews	Well no shit it cycles to maintain pressure. but if it blows warm air then cycles on and off he is mostly likely low on freon or he has a big leak. The only reason why he blows hot air in between cycling is due to improper/ insufficient flow of freon otherwise pressure would remain constant in between compressor cycles and he would not have hot air blowing. Thats why he needs to check his pressure as I am sure you already know

06-05-2007, 11:14 PM	#7
jsuh s14 Leaky Injector Join Date: Mar 2007 Location: So Cal 818 Age: 35 Posts: 97 Trader Rating: (0) Feedback Score: 0 reviews	yo.. i see that your located in socal. ill refer you to a good place for ac.. did my whole custom setup. Gardena AC & Radiator. great guy.. good prices, and fast/efficent work its right next door to the sr20 store.. if youve ever heard of it. look him up and call him.. great service

06-20-2007, 02:50 AM	#8
bees Zilvia Member Join Date: Oct 2006 Location: socal Posts: 225 Trader Rating: (8) Feedback Score: 8 reviews	thanks jsun_s14, but i wanna c if i can DIY first. so i tried using my ac again. i used it today and it seems to work fine, but only when the vehicle is moving. once at a stop (vehicle still running), the car goes into that cycle again. any suggestions? leak maybe?