smrtsmart

HI, so I have a 1990 Lexus LS400 and this morning my serpentine belt snapped. I replaced the serpentine belt and 20 minutes later the new belt snapped. I am guessing that one of the pulleys has gone bad. I originally thought that it might be the water pump, but I am not leaking any coolant anywhere. Any thoughts on how to figure out which pulley is the problem child? I'd rather not replace them all. Also, I did just replace my fan pulley bracket about a month or so ago. Also, I have a lot of tiny rubber flecks all over my pulleys now. I hope this is enough information. Thank you in advance.

RA40

iTrader: (6)

Just have to check the possible suspects. The top idler usually makes lots of noise as the bearing races loosen up. More likely the A/C, alternator or PS pulleys has seized.

smrtsmart

I know that the power steering pulley turns freely by hand as I tested it. Is the A/C pulley the one attached to the fan?

PureDrifter

iTrader: (10)

spin the pulleys to see which one is bound up...

smrtsmart

Should all of them be spinable by hand?

Lavrishevo

iTrader: (1)

For the most part, yes. Should be fairly obvious which one is worse then the others.

LScowboyLS

they should all be spinnable, however the A/C pulley can fool you, as a locked compressor could in some cases result in a snapped belt, as it has a clutch that engages whenever the A/C comes on - was the A/C or front defrost on when they snapped?

you can reach inside the A/C pulley and turn the compressor by hand, it should be somewhat hard to turn, but it should turn, you will know you are turning the compressor because you can see the middle portion inside the pulley turning, and it will be much harder to turn than the pulley itself! - a locked up A/C compressor will not turn at all.

vos

Can someone please help me? I have a 1999 Lexus Gs400 the pulley over the water pump the one with 4 screws in it is making a knocking sound. If I change it do I have to change the water pump. Hope this make sense please help

YoshiMan

No, the 1UZ-FE differs from your typical engine in the sence that the waterpump does not have either the cooling fan or anything conected to it that runs off the serpentine belt. It relys solely on the timing belt.

That thing you speak of is either the fan bracket, for models that have an engine driven fan, or the pump from the hydraulic fan.... Although i think they phased those out early on, and i am not familiar with the GS at all...

Also just giving you a heads up, you are in the LS400 forum. The guys over at the GS forum would be able to give you better details on things specific to your car. Welcome aboard.

vos

Hey thanks a bunch, I'm new to this forum the info you gave is greatly appreciated. Thanks again