This probably would have been answered if I searched, but since its down...

Does anyone know where the low-pressure service port is on the air conditioning system for a 98 Maxima? I bought a can of r134 refrigerant cuz my AC seems to be getting weak. Any help is appreciated.

 

Does anyone know if its the little blue cap that has the letter L on it, located on the half metal, half rubber hose than runs on the passenger's side of the engine compartment from the firewall and then to the bottom of the engine somewhere?

 

It's the blue! Blue is for low side pressure. Red is for high side pressure

 

one is on the left side of the condenser and the other is next to the power steering resovoir. the caps have L and H -high/low

 

thanks for the responses...

do I need to measure the pressure at the low side before adding any refrigerant, and if so, what should the pressure be when the system is full?

 

I dont remember the pressures but if you have a shop manual then you can get the specs. btw do you have a pressure manifold guage? are you recharging it with those drop-in bottles or are you using actual 134a tank?

 

I'm using the can from Castrol.. It comes with the hose and the valve to attach to the system.. So would it be really bad if I just emptied the whole can in there without checking the pressure?

How much does the gauge that I need cost? Sorry for so many questions

 

As for the gauge, they are relatively cheap at AutoZone. You may even be able to "rent" one from a store like that for a small deposit.
According to the FSM, low side pressure varies by ambient air temperature. 68-77 degrees (F) it should be 20-24 psi. 86 deg F will be 21-26 psi, 95 deg F=23-27 psi, and 104 deg F=24-30 psi. These are all at 50-70% relative humidity. Also, test conditions are doors closed, door window open, hood open, temp setting is Max Cold, Discharge air is face vent, Recirculation is ON, Fan speed is 4, RPM is ~1500, and operate AC for 10 minutes prior to testing.

I do know from personal experience that if you overfill the system, the clutch on the compressor will not engage due to some kind of safety thing. Basically, it will blow hot air. If this happens, just vent some pressure. This is why I bought a gauge! So, to answer your question, it could be bad to empty the entire bottle in there.
PM or email me if you need further info. Hope this helps.

Dave

 

So how did the recharge go? I have a 98 SE and I also need to add a little refrigerant. I was wondering if it was as simple as getting the bottle off the shelf at the local autoparts store and attatching the hose and adding a little or alot. Just wondering how things worked out. Or if anyone else would like to add anything it would be helpful

 

Usually,the A/C system is sealed,so under normal conditions,you shoulnd t need to recharge it. Unless...there is a leak.As far I know, the leaks are happening due to hardened or cracked seals or gaskets. Of course ,there is a chance to have a leak somewhere else.You could find it sometimes by simple visual inspection,so look for oil signs(remember,there is oil in the refrigerant,so just adding refrigerant may hurt th compressor,if there is not enough oil)
Labor for those is not cheap,and that due the machines.And always there is a charge to find the problem.
Someone in the forum said that if you overcharged the system ,may shut it off. As far I know,he s right.If there is not enough refrigerant and oil as or overcharge ,would shut off to prevent compressor($$$) damage.
To get it to your question,the LOW valve has the blue cap.You have nothing to do with the HIgh pressure.Anyway,the charge hose will fit only the low.
About pressure ,I charged one in a different by adding refrigerant & oil from a can,little by little.I did it with the engine running,and I kepth touching the pipe.Once charged,the pipe becomes cold,from warm. If you need to do this too often,you may need to fix the leak first.
Hope it works for you...it did for me.

P.S. Make sure you protect your eyes when working on the system.

 

Well I don't think I have a leak. It's just that my car is a 98 and it doesn't seem to be getting as cold as it did when I got it. Maybe its these hot TX days coupled with the leather. Either way I'll take you advise and refill it a little at a time and if it leaks out again, then I know I have a leak. Oh BTW, does the AC have to be running while you're filling it?