CarTalk.com Best of Deals Car Reviews Repair Shops Cars A-Z Radio Show

Recharging 1999 Nissan Maxima A/C

I have a '99 Maxima and when I turn on the A/C it just blows warm air. I did a little digging and it seems like it may be worth trying to recharge myself. I did see in some other forums that people think this may be a bandaid solution and may not expose larger problems. However if it is blowing without warm air many say it may be worth trying to just recharge if it fixes the problem for a while if it only costs $60-80. Do you guys think that this is the case? Also is it safe to do it yourself? I saw in my car manual a warning that said “A/C service should only be done by a certified technician with the proper equipment.” However, I have seen youtube videos of people doing it themselves and it looked fairly simple. I figure maybe some of these disclaimers are perhaps just for legal precaution. I appreciate any input. Thank you.

The first thing I’m going to ask is, do you have access to a set AC manifold gauges?

If not, take the vehicle to a certified AC service center.

Tester

1 Like

I and others say this is not a good idea . There is a reason why AC shops have to be licensed .

1 Like

It’s most likely not even worth trying until you know that it has no leaks and you know how and have the equipment to properly evacuate and fill it. Maybe it’s just low on gas but most likely you are just throwing money away by trying to fill it.

OK, it seems like leak detection may also be not for the faint of heart as well unless you know what you’re looking for as well? Is that the case? Probably worth having it taken into a technician?

No I don’t. So I’m guessing may be best to have serviced. It seems tricky as well to try to find leaks since I’m not extremely familiar with where to find them and how to remedy them.

AC techs use a refrigerant sniffer to detect leaks.

These sniffers can detect leaks as small as one ounce per year.

Tester

I suppose I could have tried it myself, but above my skill level. Took it to a shop, $100 for a recharge and dye, 2 months later dead again, $400 for a new condenser replacement and recharge. Too bad it got rear ended, could have saved $500 for probably 3 weeks of use.

I successfully recharged my vintage Toyota’s (1979 Celica) myself two years ago.
It had a leak (only one, I thought), and I had previously let a shop “top it off” with R12. That was three years ago. In one year, it wasn’t cooling anymore. I noticed a leak in the discharge hose (between compressor and condenser). I took it to an A/C shop, and the tech there made up a new hose for me.

I bought some tools (manifold gauges, vacuum pump, and fluorescent dye). After installing the hose, adding some oil, I pulled a vacuum, and checked the gauge readings two hours later. There were no leaks (for now). I added one can of R12 (from ebay about $30 each). Before adding the second can, I noticed that the low pressure gauge was indicating a vacuum. Not good. I called my friend who did the hose, and he said it’s the expansion valve. Second trip to the shop (to have the system evacuated), and purchase of a second receiver/drier. I pulled the cooling unit and installed a new OEM TXP valve on the evaporator.Thought I was home free. Nope.

Pulled a vacuum, and noticed that system would NOT hold vacuum this time! I looked all over under the hood for the dye with the U/V light. I couldn’t find any dye.
Time for another method of finding a leak. I bought a $40 leak detector similar to what Tester posted. I ran the car, and this leak detector started beeping when I opened the car door. Apparently my leak was in the evaporator unit. I pulled the evaporator unit again,
looked for dye, and found a trace amount on the electrical prongs of the pressure switch. I can only guess that with the expansion valve stuck closed, pressure had built up and escaped through the prongs of the switch. I installed a new switch

Pulled vacuum again. It held vacuum. I charged the system by weight (the cheapo Four Seasons receiver does not have a sight glass).

So, it cost me $45 for the manifold gauges, $75 for the Pittsburgh Vacuum pump from Harbor freight, $30
for the leak dye and U/V light, $100 for three cans of R12, $75 to have a new discharge hose made up, and $40 for an Elitech leak detector from Amazon. Oh and I had paid $20 for the EPA 609 test and free study guide from Esco, so I could buy the R12.

If I had to do it again, I would have a shop do it. But NO ONE wanted to work on this car without converting it to R134. And the lowest estimate I got was $1200, since the evaporator “may have to be replaced”, I was told. (It wasn’t). So I still saved money, the A/C still blows cold. And I got to keep the tools. But it was an ordeal.
So do yourself a favor, and take the easy way out with your R134 cooled Maxima - take it to a shop.

Why didn’t you just pay to have your 1979 Celica converted to R-134a . . . ?

If nothing else, it would make getting refrigerant a lot easier, and more shops would be comfortable working on the car

A 1999 Nissan has R134a refrigerant.

Tester

Yeah, I’m aware of that, Tester (Montreal Protocol, which is drummed into our heads as part of the 609 cert process). I was just giving the OP examples of what can happen during a repair (in my case having multiple faults with the A/C system).

I made my decision to DIY when everyone assumed I needed a new evaporator (and wanted megabucks to fix). One of my other cars uses R134, and never cooled as well as the R12 Celica. Yeah, I know that it gets cold probably because of the small interior, but it’s running great.
I’ve seen some prices for R134, and they seemed high to me (I expected $10 per can, due to the availability) . R12 is easily available, and the online sellers simply ask for a copy of the 609 certificate