A/C issue??

[NightRiderQ45]

The temp yesterday was 102 deg here yesterday and it suppose to be very hot for the rest of the week. Well....I got in my car yesterday after being parked for over 8hrs (plus it didn't help that my car is black) and my car was reading 121 degrees and it felt like it! I notice that my A/C was blowing hot air and continued to blow how air. The A/C did get cold until I started driving and once I got to a traffic light it didn't blow cold anymore. Is this normal or is it because of very high temperature? It doesn't do this unless it's very hot outside. If I'm on the interstate, it's constantly blowing cold. What do you all think is the issue?

Before maxnix ask, I haven't done any a/c maintenance on the car since I've owned it (1/05). I don't know of any maintenance you can complete with a/c systems. I'm thinking that I might have to shoot some freon in it. My car is 11 years old so I'm thinking that if I add some freon, this should solve the problem since I'm quite sure it hasn't been recharge since coming off of the production line.

[maxnix]

Before maxnix ask, I haven't done any a/c maintenance on the car since I've owned it (1/05). I don't know of any maintenance you can complete with a/c systems. I'm thinking that I might have to shoot some freon in it. My car is 11 years old so I'm thinking that if I add some freon, this should solve the problem since I'm quite sure it hasn't been recharge since coming off of the production line.

If it needs a recharge, don't you think there is another problem which needs to be addressed? Like a leak?

As Q45tech has detailed numerous times, a fluid exchange of the AC compressor involves vacuuming the R134a and lubricant out, replacing the drier, then refilling with exactly the correct amount of R134a and the specified lubricant. Is your cabin filter new? Does your outside ambient temperature sensor work? What condition is your automotive coolant system in?

1998 TGY33 don't have the rear sun screen, do they? Do you use a fitted windshield reflector screen?

Kind of makes you wonder what your ATF temperatures are and gald you installed that auziliary ATF cooler, dossn't it? Think of all the newbies with RE5 (Y34, 3rd Gen Q45, Y50, QX56) who have not!

[goody90q45]

Top off the freon and it will be fine.

[qship96]

"top off" of refrigerant is NOT the way to do it!!!! Evacuate,leak test, refill to EXACT WEIGHT....then evaluate system performance to determine if other parts are failing{compressor becoming weak at low engine rpm but satisfactory cooling at higher rpm is typical first sign of dying compressor}

Without having the EXACT WEIGHT of refrigerant in system, diagnosis is a crap shoot at best....and the ONLY way to determine if exact weight is in system is to evac. and recharge......topping off just complicates proper system diagnosis

By the way, I just got done using Frost King air conditioning foaming cleaner in aerosol can on condensor coils{ bought at Lowes,$5.89} and Einszett Klima Cleaner expanding foam evaporator cleaner on my Q.....dropped vent temperature by 3 degrees- not bad for 15 minutes of my time and less than $20 investment. Highly recommended!!!!!

[NightRiderQ45]

Maxnix I haven't changed the cabin air filter yet but it's on my "to do" list. My automotive fluid is great. I changed that almost a year ago. My car doesn't have the rear window screen but I do use a fitted windshield screen for my car (but I forgot to put it in yesterday thus the hot temp...windows wasn't cracked either).

Qship I think you hit the nail on the head! Your statement of "{compressor becoming weak at low engine rpm but satisfactory cooling at higher rpm is typical first sign of dying compressor} is exactly what my car is doing!! When I say top it off with freon, I'm speaking of doing all of the steps that you and Maxnix stated. I've never known of any a/c shops who doesn't do that. All of my previous cars were serviced the same way.

I will have my a/c system serviced next week to see if it changes anything. If it doesn't then I'm quite sure my compressor might be dying...I mean 11yrs old, I think that's great!

Oh, please give more information about what you used to drop you temperature in the car. I'm quite sure that my car needs it. Did you just spray it on the coils or did you have to pump it into the system?

[qship96]

Spray on exterior of coils, it removes the insulating dirt/grease/tar/dead bug bodies allowing better air flow and heat exchange- good to do radiator also if it is older/dirty

My compressor became weak at idle with reduced cooling,but was cooling well at higher engine rpms.....this was at 11 years/195,000 miles-new compressor fixed the problem!

[NightRiderQ45]

Thanks for the reply. Before I confirm if it's the compressor, I will have the a/c serviced first. I glad that you have first hand experience with a faulty compressor. What I will check today is to make sure that the fans are running when the a/c is on. What could be the problem is that the freon is not getting cooled enough. The reason the AC works fine at speed is that there is enough air flow through the condenser to suck the heat off that the freon picked up. When the car is stopped there is not enough air flow.

Does my statement above make any sense?? Oh I will try you cleaning solution too. I can't beat that for $6. I wonder if they sell this product in Wally World or AAP or AZ?

[Q45tech]

At 322,000 miles and 19 years I'm on compressor number 3 but I am a stickler for as new performance.Even the oem remans don't last much over 100k whereas brand new as built in Japan seem to be ok until 150k minimum.

[NightRiderQ45]

That's great to know tech but do you have any insight of the problem that i raised earlier in the post? Qship, I googled that klima cleaner and it states to spray through the central a/c vents in the interior. If I remember correctly, I think that my central vents has a screen behind vents.
Modified by NightRiderQ45 at 1:02 PM 6/24/2009

[qship96]

Yes, after evac/recharge, but before replacing compressor due to weak cooling at idle, double check to be sure it is not an airflow problem due to bad fan clutch/worn out condensor fan/dirt blocking condensor.....if all that checks out, then it is probably the compressor becoming weak and needs replaced{ thats how I diagnosed mine....eliminate all other variables first}

When I bought my compressor from Joe in 2007, I bought a brand new genuine Infiniti part, NOT a factory rebuilt one- was rather expensive.....would have been cheaper to go to home Depot and purchase 4 home window A/C units and lower the car windows and shove one in each window and wire up an power inverter to power them!!!! Works like new though, so I am happy- I cant stand to be hot!!!!!!

Klima Cleaner is for evaporator cleaning- hose is snaked thru dashboard a/c vent to reach evaporator box.........the Frost King coil cleaner is sprayed on condensor under the hood and rinsed with garden hose

[elwesso]

IF you want to save yourself a few bucks, go buy yourself a manifold gauge set and read the pressures yourself, its easy to do and you can diagnose your own AC problems.. IF you are low on refrigerant, it should show up on the gauges..

In my opinion, you can tweak refrigerant level a little band-aid a weak compressor, but ultimately you are going to be looking at a compressor after a while..

I own a vacuum pump and manifold gauge set, so all I need is a recovery tank and I can do my own AC work...

If you take it to a shop be sure they purge the lines well and maybe pay them a little extra to keep it on the machine longer, any air in the system will cause issues with the variable displacement compressor.

[NightRiderQ45]

Thanks for the reply Wess. I will be sure to do that. I think that I might have found my problem. After turning the a/c on, ONLY one fan is running (the fan on the driver's side). I would think that both should be running at the same time right? I guess that I need a new blower motor (I guess that's the motor that turns the fan)?

Qship, I don't think that klima method will work on my car unless I take the console apart. I do have the screen right behind my center a/c vents. I confirmed that yesterday too.