# 2000 Altima - hissing, grinding, clank sound when idle



## BillHoo (Nov 13, 2006)

2000 Altima, over 350,000 miles.

Been less than a month since I welded up the rusty flange on the cat. Last weekend. I took the car for a 500 mile trip.

Coming back, I heard a grinding, tinkling sound while idling at the light. I thought maybe my welding job had broke and the cat was hissing again.

Went under the car with engine running to see if I could feel exhaust escaping from the seem.... Nope. Seems OK!

Popped the hood and hear a hissing, grinding noise coming from the belts with occasional tinkling bell sound... maybe near the alternator. All belts seem to be moving. When stopped, all the belts seem tight. Not sure about the pulleys.

I didn't have much time last night, but I got my long handled screwdriver to "listen" for where the sound was coming from.

It was more pronounced coming from the AC compressor. I was hoping for just an idler pulley to be replaced.

I'll jack it up this week and remove the passenger wheel and splashguard to see if I can loosen the belt(s). My intent is to:
- Check the idler tension pulley to see if that is where the grinding is from (bad bearing?)
- AC Clutch pulley (bad bearing)
- AC compressor (bad compressor?)

I haven't had function AC for a few years now. I had previously tried replacing sensors around the evaporator.

I was going to replace the in-cabin air filter this spring and see if maybe there might be a mouse nest in the evaporator. When the AC stopped working the AC would sputter and spew water at the floorboard on the passenger side. I have blown out the drain hole and seen a ton of liquid come out. Also, the AC seems only work when temps are below 80F outsid3e. That's why I replaced the sensor.

I suspect a rodents nest in there. Maybe it's the AC compressor/clutch?


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## smj999smj (Jan 1, 2006)

I think the cabin filter was optional in that year. Some had it and some didn't. If it didn't, you could install one; I know on my 2003 Frontier, I had to cut a panel out on the side of the evaporator case to install the filters. If you don't have the filter, the evaporator drain probably got clogged by leaves and other debris that got into the case. 
I would take the drive belts off one at a time and start the engine to see if the noise goes away. If it does, you can check the components that are driven by that belt for the potential cause. It could be the bearing in the clutch or the compressor; most would replaced the compressor and clutch as an assembly, anyway. Hopefully, it's just an idler pulley, but it could be the water pump or even the timing chains that are making the noise.


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## BillHoo (Nov 13, 2006)

Got around to jacking up the car last night.

Cover inside the wheel well was gone. Probably from previous idler pulley and belt repair at the dealer. I never did work in this area and it was the dealer that made those repairs in 2010 when I was stuck roadside after the belt broke. I recall they charged me an arm and a leg for the tow and replacement of the idler pulley and belt.

Anyway, the 14mm bolt holding the lower tensioner pulley was a breeze to turn! I was worried it was going to be rusted solid. Same for the 14mm nut holding the idler tension pulley. Easy peasy removal.

tensioner pulley was still in great condition. Rolled smooth and fast with no noise.

Belt was also in great condition.

The AC clush pulley... not so good. Hard to turn. Made the grinding noises and tinkling sound as I tried to roll it. Also I could see little shiney flecks of metal coming out of the clutch.

With the belt removed, I started it up and it sounds pretty quiet. The remaining serpentine belt drives the Power Steering pump, Water pump, and alternator. Everything is good. 

I think I'll leave the belt off before considering repairing the clutch bearing.

It's a tight squeeze. I may be able to get a socket in there to remove the clutch. there's a YouTube out there where someone jams a flathead screwdriver into a slot on the clutch disc to immobilize it while loosening the bolt (10mm I think). They caution to remove it carefully as there are spacer washers in the spindle that could fall out and get lost easily.

Another way to get access would be to loosen the four 14mm bolts holding the AC condensor in place. This would allow the condensor to move and allow access to the clutch/pulley.

Either way, I'm not tackling this right now. 

With the loud hissing, grinding and clanking noise gone, I can hear the faint hiss of my catalytic converter. I think my weld last month is developing a few holes.

I need to bring the car for Safety Inspection in the next two weeks. Even though emissions is not part of it this year, they might gig me if they detect a leak from the cat.

It might be I just need to tighten the bolts a bit more after I put it back together last month - just settling down and need additional tighten. Or indeed the weld is not a good enough repair for the flange that was nearly rusted all the way through!

I think my strategy will be to just bring it in and hope the inspection doesn't look near the cat. If they say something, I'll react accordingly. If not, I'll leave it be until the next time I have to jack up the car.


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## BillHoo (Nov 13, 2006)

btw It passed the safety inspection somewhat easily. 

New inspector at the shop I go to. Tried to say that the car was unable to start without stepping on the gas and put it on a list of minor fails (headlights too dim, bad interior rear brake light, etc.). I came back to the shop and brought the state police inspection manual and argued that starting the car was not a fuel system fail. I won.


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