Air compressor noises & questions

[Panbacca]

Ok, so a couple of things. Since it hit 100 degrees in sunny Lincoln today, I was using the a/c.

My 2003 has 78k on it right now, and I don't know if the a/c has ever been recharged.

Should this be something I need to look into? It wasn't exactly blowing as cold as I would have liked it to. I'd say after 20 minutes of driving, it finally started to cool the cabin down.

 

That is my first question.

My next question is regarding the compressor, and a noise it makes regularly.

When I first start my Pathfinder, and put it into drive, within a few seconds I can hear the compressor "noise" kick on for a split second, then turn off. Almost as if it's doing some sort of "check"... If that makes sense.

So...in summary: From park, right after putting it into drive, I hear a "sigh" that sounds like the compressor.

Does this mean anything? Does anyone else's do this? I've had it almost a year, and it's always done this...

Edited May 10, 2011 by Panbacca

[Towncivilian]

Not sure whether this is applicable, but FWIW some sort of pressure line hose had to be replaced and the system recharged about 31k ago for me. Your system might be low on refrigerant or be leaking, but I know very little about A/C. Maybe see how much Nissan will charge to recharge your system? With summer time approaching every corner shop claims to have an A/C specialist but really they probably just use the same refrigerant in a can crap you can buy and do yourself, which probably isn't the best way to go, especially if it includes stop leak stuff.

 

Also, check your in-cabin air filter and replace if clogged. That would help a little, but it sounds like you have larger issues with the compressor possibly.

 

I also hear a "sigh" frequently after first taking off. It's most audible if just creeping, not applying any throttle when going forward. It's heard after a few feet of movement. I don't think this is your compressor, as this happens even if the A/C is off. Does anybody know what this is, actually? I've always been curious. Is it ABS running a self-test?

Edited May 10, 2011 by Towncivilian

[Howie]

Sounds like you have a leak in your system and have lost pressure. I had to have my low pressure side replaced, like the other guy. See my thread for how I saved a lot of $ by having a hydraulic shop repair my line instead of buying a $125 part.

 

Best way to get started on this is invest $40 on an A/C diagnostic manifold. You can pick one up at Harbor Freight: A/C manifold (it's listed for $50 here, but you can get them for cheaper in the stores if you have one near you). Instructions on the manifold combined with the section in the shop manual will tell you whether you have a leak in the high pressure side, low pressure side, or compressor itself. If you have problems with this step, feel free to PM me.

 

You might have the fluorescent dye in your refrigerant from the factory. This will be indicated by a green sticker under your hood. If you do, you can get a UV light, shine it on your A/C hoses and see where the leak is. Get a UV light from Harbor Freight for a few bucks. If you don't have the UV dye in your refrigerant, you can add a can of the stuff with the dye in it. You'll be able to tell right away where the leak is.

 

If the leak is on the low pressure side, I recommend doing what I did and finding a shop that will fix your hose instead of buying a whole new low pressure side. See my thread for details on that.

 

Good luck!

[Panbacca]

Thanks for the advice!

I do have a harbor freight nearby, I will look into that tool.

 

It's weird. Some days the A/C works ok, some days it doesn't. I don't understand it. Guess I will just have to see if I do have a leak.

 

Towncivilian - That is when I hear my Pathfinder's "sigh". Not sure what it is, but it is within seconds of putting it into drive that I can hear it. I guess if it is normal, I won't worry about it... But I'd just like to know what it is.