2002 Dodge Grand Caravan eL w/3.3L 41TE and 210k miles.
This year Mini-Van and many Chrysler products have a decoupler pulley on the alternator, a one way clutch to let the alternator overrun the motor, for less stress on the drive belt and tensioner. As I've been reading, these seldom last the life of the vehicle and often need replaced.
I've had a pretty noticeable squeal from the accessory drive belt of this vehicle. Replaced the Serpentine belt, it needed it. Reduced it some, but it was still there, more of a squeak than a squeal, it is definitely NOT a slipping belt.
Replaced the pulley wheel on the tensioner (it needed it) the aftermarket replacement was metal instead of OEM plastic and every so slightly larger in diameter (like an 1/8th of in), but it seems to be working fine.
The squeak is still there. And its NOT constant, nor is horribly bad, but its noticeable every few seconds there is a squeak. It seems loudest from the alternator area. I used a short broom stick to the different accessories to my ear, I'd be damned if that doesn't actually work, its a totally different sound, but sure enough its a sound you can tell if its normal or wrong. The alternator sounds is inconsistent, even gravelly but I don't think a squeak sound carries over the broomstick.
So, is there a way to tell if I need a new alternator or just a decoupler pulley?
From what little I gather, a bad Decoupler Pulley makes a rattling sound, NOT a squeak. But the decoupler pulley has a bearing in it as well as the alternator.
I did some of the tests for the Decoupler Pulley, and it looks like its bad.
Have a helper run the engine up to 2500rpm and turn off ignition at that rpm, the alternator should continue to spin, in my case it stops with the engine. Another sign of a bad decoupler is one that makes noise as the alternator continues to spin after the motor stops. With the belt off, I can turn the alternator pulley and try to turn it the opposite direction and the alternator turns with it (from what I gather that is NOT a valid test, a new Decoupler should work well enough that you should see some decoupling trying to turn the opposite directions quickly, but a worn but still good one will resist it more, you have to stick something in the fan of the alternator to put up some resistance.).
Here's the thing, if the alternator is bad, I don't want to pay for a new decoupler just to find out I wasted that money and have to buy a new alternator that will have a new decoupler pulley on it. Anyone have a better idea how to narrow this down to decoupler or alternator?
I think this an unrelated cause, because the PS pump sounded OC, but NOT as smooth as the water pump and AC clutch or tensioners, the idle tensioner was almost silent. On first start in a cold soaked vehicle, below freezing temps, twice we have noticed a sudden loss of PS boost when trying to turn the wheel to quickly, only for a second, and there is no associated belt squeal. It is likely internal hydraulic and related to the cold. Cause it goes away right away and doesn't come back. Heck it might just be cold fluid in an older weaker pump and rack.
This year Mini-Van and many Chrysler products have a decoupler pulley on the alternator, a one way clutch to let the alternator overrun the motor, for less stress on the drive belt and tensioner. As I've been reading, these seldom last the life of the vehicle and often need replaced.
I've had a pretty noticeable squeal from the accessory drive belt of this vehicle. Replaced the Serpentine belt, it needed it. Reduced it some, but it was still there, more of a squeak than a squeal, it is definitely NOT a slipping belt.
Replaced the pulley wheel on the tensioner (it needed it) the aftermarket replacement was metal instead of OEM plastic and every so slightly larger in diameter (like an 1/8th of in), but it seems to be working fine.
The squeak is still there. And its NOT constant, nor is horribly bad, but its noticeable every few seconds there is a squeak. It seems loudest from the alternator area. I used a short broom stick to the different accessories to my ear, I'd be damned if that doesn't actually work, its a totally different sound, but sure enough its a sound you can tell if its normal or wrong. The alternator sounds is inconsistent, even gravelly but I don't think a squeak sound carries over the broomstick.
So, is there a way to tell if I need a new alternator or just a decoupler pulley?
From what little I gather, a bad Decoupler Pulley makes a rattling sound, NOT a squeak. But the decoupler pulley has a bearing in it as well as the alternator.
I did some of the tests for the Decoupler Pulley, and it looks like its bad.
Have a helper run the engine up to 2500rpm and turn off ignition at that rpm, the alternator should continue to spin, in my case it stops with the engine. Another sign of a bad decoupler is one that makes noise as the alternator continues to spin after the motor stops. With the belt off, I can turn the alternator pulley and try to turn it the opposite direction and the alternator turns with it (from what I gather that is NOT a valid test, a new Decoupler should work well enough that you should see some decoupling trying to turn the opposite directions quickly, but a worn but still good one will resist it more, you have to stick something in the fan of the alternator to put up some resistance.).
Here's the thing, if the alternator is bad, I don't want to pay for a new decoupler just to find out I wasted that money and have to buy a new alternator that will have a new decoupler pulley on it. Anyone have a better idea how to narrow this down to decoupler or alternator?
I think this an unrelated cause, because the PS pump sounded OC, but NOT as smooth as the water pump and AC clutch or tensioners, the idle tensioner was almost silent. On first start in a cold soaked vehicle, below freezing temps, twice we have noticed a sudden loss of PS boost when trying to turn the wheel to quickly, only for a second, and there is no associated belt squeal. It is likely internal hydraulic and related to the cold. Cause it goes away right away and doesn't come back. Heck it might just be cold fluid in an older weaker pump and rack.
