I have a '99 Frontier (3.3L V6) just had the radiator, hoses, fan clutch and 3 exterior belts replaced. Car’s not overheating anymore, BUT, now I hear intermittently a “clack” (which sounds similar to a loud compressor when it shuts on and off). Car never made this sound before the repairs mentioned above were made. I took pictures and could use help finding out what the part is called that is making the noise. I see the 3 discs on the front side of one of the belt pulleys (i think?) spinning, then they will stop, making the clack sound. It seems to me that sometimes the sound is loud and then other times it is extra loud --are there two sets of these discs and the other set is somewhere I can’t see?
Most importantly I want to know if this is something that had to do w/ the repairs the mechanic did and should he fix for free?
That is your AC compressor clutch. It has always made the sound, you just couldn’t hear it before, either because it is getting louder with age or something else made more noise in the past. The belt might be a little too tight right now too.
So to be clear, it is perfectly normal for the 3 discs to spin, and then when necessary (for whatever reason) they stop spinning (car still running), and then later they will cycle back to spinning? is the belt tight because it is brand new or is there a related tensioner that needs to be adjusted?
Lastly, is there another clutch somewhere nearby I am not seeing that is making the louder “clack” that I sometimes hear?
The A/C clutch is working as it’s supposed to, yes. I would guess (since you just had the clutch replaced), that the old one didn’t work properly, or at all. Now you’re hearing it for the first time.
Before you could hear the clacking, did the belt squeal? Did the A/C even work? Is it possible you’re just a bit more sensitive to any noises because you just had work done?
I can’t think of any other driven component mounted on the motor that would make that noise. Of course, I may be wrong, but nothing I can come up with would sound like that.
To clear up, the fan clutch was replaced, not the AC clutch. Usually, when a fan clutch is going bad, it makes a lot of noise, that could have masked the normal sound of the AC clutch engaging and disengaging.
Yes it is normal for the three discs to be spinning sometimes and sometimes not when the AC or defroster is on. If the AC is off and the HVAC control is in any position but Defrost, the the three discs should not be spinning at all.
There is a separate tensioner for the belt. The only way to get this belt off is to loosen the tensioner first, so when a new belt is installed, the tensioner has to be adjusted. Generally the belts stretch a little over time. When the new belt is installed, the tensioner is adjusted for the proper tension. As a result, it will probably be tighter than the old belt was when it was removed.
Find the longest section of the belt, then put your finger in the middle of this section. Now either push or pull with that one finger only and the belt should deflect about 1/2 to 3/4" with moderate tension. This is not an exact measurement, but it should be close. To actually adjust the tension, a scale is used, but if you can’t get at least a 1/2" with one finger, the belt may be too tight and that might make the sound louder than it should be.
If the a/c compressor clutch is noisier due to age, is there maintenance that should be performed-- should it be lubricated or something like that? When the clack is REALLY loud, it definitely sounds like something is not right, but the other times it is loud enough to hear while driving with the windows up, but it sounds in the “normal” range, nothing shocking… I would describe the extra loud noise more like a banging clack that a home hvac compressor makes when it tries to start but doesn’t get going and shuts back off. Hope that helps
I should have said the louder, banging clack is SIMILAR to a home hvac compressor, obviously not as deep and loud, but definitely more of a “wow, that’s a loud clack, what the heck is that?”