Pito Chueco

Well its Summer time here in Texas so that can only mean one thing:

My AC decided to take a break. (00 Frontier V6)

Here is the scenario. I had a slow leak on the high side AC line. I replaced with a new hose and had it charged at the shop. All was well for a few months, but then I started to notice that it was blowing warm. I put a few ounces of freon in, since it was just on the "add" line on my guage, and thought all was well again.

No such luck. Basically, if I drive the truck the AC works fine until I stop and start it again. At that point, the clutch AC clutch usually doesnt kick in. After driving for a bit longer, it will intermittently start blowing then stop again.

I have confirmed my freon is fine and I have no leaks. Any other ideas? I have had pretty good luck with this truck until about 140K, now it seems as everything is going south and I am ready to drive it off a bridge.

Thanks,

Cusser

Sorry, I can't believe what you posted. Why do I state this? Yours has no freon, you have R134a; "freon" is DuPont trade name for its R-12 refrigerant.

The real way to determine if your charge is correct is to recover it, and weigh it, but that takes special equipment. So if you really think your refrigerant level is OK (maybe from a single cheapo gauge?), we need more information to help you. Post both the high and low side pressures at 1500-2000 rpm after 5 minutes of running the AC. Also post the outside ambient temperature and the temperature of the air coming out of the vents. That's the only way to get real help.

Pito Chueco

Thanks Cusser.

I have been using a cheapo gauge, so I rented a good one. Here are my readings:

It is about 95 F today. At idle when the truck is warm, I was getting 425psi on the high, and 47psi on the low.

After I let it warm up for 5 minutes, I reved up to 2000 rpm. When I did that, the high pressure climbed to over 500psi, then the compressor shut off. When I went back to idle, it kicked back on.

I suspect that I have too much pressure (too much refrigerant?)

What should the reading be?

Pito Chueco

Follow up: I spoke to a home AC person and explained my problem...said I definitly have too much refrigerant, but he didnt know what exactly I should be shooting for.

I released some and I am now at the follwoing readings at 2000 RPM:
High: 325
Low: 27

Thanks,

Cusser

OK, now we have some information. Your original pressures were WAY too high, both low and high sides. That means either you have air in your system (like system was evacuated properly before adding refrigerant) or you have too much R134a refrigerant, problem with coolingg fans/fan clutch, or a combination of all. Your newer pressures are better; but a good rule of thumb is that high side pressures should be about 2.2 times the ambient temperature, or like 220 psi on a 100 degree day. So 325 is still too high, either too much refigerant or fan/fan clutch issue compounding the problem.

http://www.napabeltshose.com/downloa...s&view=napa_hc