AC in Hot Weather - Wear

[xmateo]

How much extra wear is incurred when the AC is running in HOT HOT weather? My 1993 J30 seems to get really bogged down when tempuratures reach over 95 degrees. Will I add extra years to the transmission and engine if I don't use the AC in extreme heat? transmission and engine are serviced regularly.

Also, the AC coolness is pretty weak. Not sure if it is worth getting recharged if I don't use it. Sounds foolish to not use, I know (but $$ is tight for a bit).

[elwesso]

AC use doesnt really put THAT much extra strain on the engine. If you have a transmission cooler you should be all set... If the engine isnt running just right, i would imagine it would get very slow and boggy.... but using the AC wont make life better or worse, unless your putting that extra strain on the cooling system, ie if its not up to par...

I love ICE COLD AC and I will always use it... NO sense in having a luxury mobile without AC.....

[Q451990]

Can't imagine not having or using A/C in AZ! I think I'd have my home phone turned off before going without it... The bogging down you mention sure sounds like a low charge to me. Didn't the 93 models use R134a refrigerant? If so a trip to AutoZone or Wal-Mart will take care of the refrigerant and a kit to put it in... use the graph in the FSM and a good thermometer to gauge the output temperature.

If it's R-12 DO NOT try one of those conversion kits. The only real conversion from R-12 to R134a is a new compressor, condensor, and evaporator.

Heath

[DAEDALUS]

93 was the first mandatory model year for R134a. The bogging only occurs with the AC on when the engine's hot, or anytime the engine's hot?

[SpecDRacing]

As stated, bogging in hot weather is a bit general of a description. The AC shouldnt cause this, even with a low charge. Make sure, if you do go to add R134 to your system, that you have ir properly checked for the amount aleardy in the system. Overcharging can lead to an underperforming AC system, loss of cool air, or even a/c component damage. Preasures in an AC system reach in the in the 180-220 PSI range depending on vehicle, so overcharging can definately damage or malfunction the system. In some cases, the system wont come on at all as the cars diagnostics will see the excessive preasure and dissengage the ac clutch.

As for power loss, you should start with the basics. Has your air filter been checked recently (Q45's are known to cake an air filter in no time, J's on the otherhand stay relatively clean for 15-20 thousand miles). Has the fuel filter been replaced? Spark Plugs? Etc. As these little things can add up to a big power loss.

If the car runs good and doesnt have the MIL on, then I'd say just keep up with your routine maintenances and it should be ok (or your mechanic will let you know). Sometimes, we find ourselves worrying that our cars are acting funny....only because we beome more aware of their characteristics. If your still worried about this, just fill us in a few blanks and we'll be glad to help.

[Q451990]

As stated, bogging in hot weather is a bit general of a description.

Now that I read the post again, I see that he did mean the car - not the A/C system. I've had A/C on cars with a low charge that seem to work fine when you pull out of the garage, but get worse the longer you drive. That's what I was thinking about when I read "bogging down."

The car will perform slower as the heat rises while the ECU tries to protect the cylinders with a richer fuel mixture. That may be the difference he's feeling....

Heath

[xmateo]

Thanks for all of your remarks. I don't have a huge power loss with the AC on. I guess I should be more descriptive. Each time I depress the accelerator (with AC on), I hear a hissing fan sound (similar to what you would hear when driving an old GM van or truck). The hotter it gets outside, the worse it [seems]. With the AC off, the sound is not there.

I've noticed lately that the belt(s) squeal a bit. I hear this when I am parking the car. Its not loud or obnoxious, just a small hum. Do I adjust or replace? What about a DIYer, how hard is it to replace belt(s) on a J30. The last time I replaced a belt, it was a serpentine belt, about 10 years ago on a Chevy.

I would love to be able to change the belts and add a new AC cartridge. What is involved? What is FSM / IR? Can I do a partial charge to avoid "overcharging". How do you measure pressure and temperature?

Ultimately, is the belt the problem?

[SpecDRacing]

If you hear a hissing sound, you should check all of your rotating parts on the front of the engine. Idler pulleys on Infiniti's are not known for their stamina. Whenever you hear belt squeel, the best thing to do is pop the hood, grab some silicone spray, and shoot just a small shot onto each belt, allowing yourself enough time between shots to see which belt is making the noise. If the squeel goes away when you spray a particular belt, then you know that belt is hard/lose and needs to be replaced. If after you spray all the belts, its time to check the pulleys. On a J-30 this can be a little difficult as there is not quite enough room in the engine bay to really get in there and listen. You may try lying on the ground and listening from there. If this is belt squeel, I'd say check the belts for cracking and loseness, then check the idler pulleys. They are common to seize up.

[maxnix]

Each time I depress the accelerator (with AC on), I hear a hissing fan sound (similar to what you would hear when driving an old GM van or truck). The hotter it gets outside, the worse it [seems]. With the AC off, the sound is not there.

Have you checked all your vacuum lines?

Squealing belts are shouting to you they require maintenance now! Don't forget the tensioners.

[xmateo]

Okay. Got the AC recharged and belts replaced. The AC seems cooler, but not as much as I expected. It still seems to take some time to "ramp up" to a cooler temp. When I had it serviced, they said it only needed ½ lb.

[maxnix]

The question you have to answer now is why? Where is the component that is leaking?

You have treated the symptom, not the problem.

[RobertsnewQ]

93 was the first mandatory model year for R134a. The bogging only occurs with the AC on when the engine's hot, or anytime the engine's hot?

My 93 (9/92 prod.) has R12, funny enough. Unless the hood sticker is wrong.

[DAEDALUS]

Sorry about that. A quick google shows 1995 is the model year for mandatory usage. 1993 is stuck in my head for some reason, perhaps that's when the law was signed. My '93 FSM confirms the use of R-12.

[maxnix]

I'll be stupid here and say the 1994 G50 used R134a also.

[xmateo]

It seems that I remember something about a high/low (voltage??) switch that changes when the AC needs to blow colder / or doesn't need to be so cool. Could something be wrong with that switch?

I will check with the mechanic on possible leaks in the system first. I can't imagine there being a major leak since the recharge only required ½ lb of pressure. Not sure how much it holds though.

[DAEDALUS]

There's only 1 clutch, it's either engaged or it isn't. Probably a variable displacement compressor though. Maybe you're thinking of the dual-pressure switch?The system probably holds around 40oz of freon.

[Q451990]

I will check with the mechanic on possible leaks in the system first. I can't imagine there being a major leak since the recharge only required ½ lb of pressure. Not sure how much it holds though.

I don't think I would worry about it... depending on how long it has been since a recharge. If you're loosing 1/2 lb in a few years you're in good shape... probably not a detectable leak.

Heath

[qship96]

keep in mind losing a half pound{8 oz] is roughly 30% of the total,correct fill-significant amount to affect cooling performance!

[xmateo]

I took the car back in today to see if the technician could see any of the die to detect a leak. Nothing. However, the high/low pressure was 220/60 PSI. I was told it should be less than 50 PSI for the low.

[Q45tech]

Like 30-35 psi low at highway speed depending on temperature.......dirty condenser, leaves between it and radiator, worn out foam surround allowing hotter air----after rad to recirculate back in front of condenser; fans not turning at speed.................AND of course an improper charge or moisture in system or incorrect oil level.

All modern AC system work the same.........a certfied and experienced MASTER AC TECH with all the test equipment.

Measuring things in a shop doesn't translate well to actually driving the car with gauges attached to monitor what's actually happening in real world.

[xmateo]

Yep. Its time to replace the AC system. Any referrals to Phoenix area resources is appreciated

[Q45tech]

Noticed today that after 25 minutes at speed the AC was still using 3 fan symbols to cool to 72F [recirculate] with 101F indicated outside.Since it has been 12 months since the R12 was last checked.

Recovered [0.95Kg] but filled to 1.1Kg a year ago..........0.15Kg [5.25 ounces] missing in 26,000 miles.Vacuumed down for 30 minutes and recharged with 1.1 Kg.

As new performance returned [41F low fan speed at idle] and 72F was maintained with 2 fan symbols.

So even 5 ounces [13.5%] is noticeable much less 8

Good to go for another 12 months.

[Q45tech]

EPA site had some numbers on ANNUAL leakage of OLDER R12 systems......thru o rings and hoses..............it normally was around 3-4 ounces per year on systems that used 2.5 pounds.............7.5%-10%.

So with R12 an annual top off is usually required as the hoses age [from heat/oxygen].

It's been 4 years [55,000 miles] since the hoses/orings were all replaced so my findings seem about right............at $25 per pound .......$8 worth is cheap.

How long will my as built 15.5 year old evaporator last is the next question?

[xmateo]

I'm pretty sure my J uses R134a. I believe the window says ozone safe or cfc free - something like that. Where in the engine bay will it confirm? Hood?

[DAEDALUS]

Yeah, there should be one or more stickers on the underside of the hood for refrigerant and emissions info, and maybe belt routing and other stuff.