Getting a noise when the AC is on.

[Empty V]

So I've had this issue for a while and have finally pinned it down, somewhat. When my AC is running and the compressor is at full blast I hear a rattling noise. When the window is down it sounds like it's coming from the driver's side front wheel well. It also seems to increase when I'm pushing the tach on the freeway. Does anyone know what this could be? I haven't inspected it yet but will check it out tonight. Damn this 100 degree weather in April!

Billy

[fueler]

ac compressor it makes a rattling noise when engaged. thats prefectly normal. by the way, there is no such thing as "compressor [is at] full blast" the compressor is either engaged, or disengaged. there is no inbetween or "full blast" haha

[fueler]

it might be louder now because its been so damn hot. monday was just ridiculous!!!

also, if u didnt know, the way to turn the ac compressor off is to run "ECON" mode. when youre in AUTO mode, the compressor is on, no matter the fan speed or the temp. Even if you're running AUTO mode at 85* hot, the compressor is engaged..... pretty stupid IMO - dont ask me why nissan did this. other than the fact that it prevents windows from fogging up on cold nights windows open with the engine idling, play with the econ / auto buttons by pressing them back and forth and you should clearly hear the compressor turning on and off

[pathfinder9035]

ac compressor it makes a rattling noise when engaged. thats prefectly normal. by the way, there is no such thing as "compressor [is at] full blast" the compressor is either engaged, or disengaged. there is no inbetween or "full blast" haha

i dont know about that. The ac compressor has a clutch. If u have it at full blast, the thing spiining in the middle is moving at the fastest rate to give u maximum cooling if not the spiining thing in the middle moves slowly.

correct me if i am wrong.

i too am experiencing a wierd noise from my ac. Except its more like a grinding bearing noise. I remember eversince i took it though mud that was as deep as the tire, that noise has always been there. I think it might be the ac clutch. When i engage the ac, the sound is almost completely gone.

[SnowSurfLax]

Ok, I'll clear up the AC issue since mine has both issues.

If it's the clutch, it will whine at specific RPM's regardless of being engaged.

If it's the compressor, it will make noise when in AUTO and not when in ECON on the climate controls.

Billy - sounds like your compressor is on its way out. The good news - it's going to cost you about $500 - 600. The even better news is that it's not worth fixing (unless it's not blowing cold) as it's going to s*** itself and whether you do it now or when it finally goes kaput, it's the same price.

Good luck!

[fueler]

well i dont know how the internals of the compressor work. all i know is mine sounds exactly the same, regardless of fan motor speed or temp setting. by "full blast" i assume you guys mean fan motor on highest setting? or do you mean 65* F (lowest setting) ?

[Empty V]

well i dont know how the internals of the compressor work. all i know is mine sounds exactly the same, regardless of fan motor speed or temp setting. by "full blast" i assume you guys mean fan motor on highest setting? or do you mean 65* F (lowest setting) ?

Well it seems to be worse when it pumping out the max amount of air and I've got the tach and putting more stress on the vehicle. And it is a grinding type of noise.

Snow, thanks for the encouragement! Is this something that is easy to replace or should I have a mechanic do it? I'm somewhat mechanically inclined and believe that mechanics aren't magicians so anything can be fixed with the proper parts and tools. Unfortunately I don't have access to a lift so I don't have the proper tools.

Billy

[fueler]

im sure it can be done, ive removed plenty of ac compressors but putting them back and charging them correctly is a bit harder, i let my mechanic do that part

ive got a junkyard compressor in mine right now, works great

[SnowSurfLax]

Exactly what fueler said. You can take it out and put it back in, but it's illegal to just vent the gases to the atmosphere (on purpose anyway) and it's hard to properly charge one back up.

Have to get the correct pressure (after vac test) and add the precise amount of oil. Given it'll only run you ~$150 to get one charged by a pro, not worth the hassle, IMHO.

As far as the compressor works, it just circulates the R134 (or whatever it is) at pressure, so I think the clutch is designed to slip when RPM's get over a certain point since pressure should be constant regardless of engine RPM's.

[fueler]

exactly what snowsurflax said. except for thepart about gases in the air being illegal. Like everything, it's only illegal if you get caught

[Buzzman]

Is this something that is easy to replace or should I have a mechanic do it? I'm somewhat mechanically inclined and believe that mechanics aren't magicians so anything can be fixed with the proper parts and tools.Billy

Proper tools is the key here.You need special equipment to properly drain and re-fill an A/C system, if you want to do it properly and legally (I suggest you do).I don't know of any DIY guys that have this equipment in their garage or basement, so you should take it to a shop that has the proper gear.Good luck.