does the water pump run off of the timing belt or the fan pully/serpintine belt? I recently changed the serpintine belt and now the fan pulley rocks and makes noise and I get a rocking noise coming out of the engine....ind of confused as as to what is going on, are they related or are they two seperate things going on?

G'day,

I'm assuming that you are talking about the V6?

If so, then yes, the water pump is driven by the timing-belt. It is mounted into the front of the engine block, behind the timing covers.

In regards to your noises - try running the motor without the serpentine belt - that will eliminate noises coming from it's drive train.

Noises from the timing-belt train could be: water-pump, idler pulley, tensioner pulley or faulty hydraulic tensioner.

Do a search on 'tensioner' over the last few months

soory forgot to say....it is a '99 trooper 3.5L. The mechanic I showed it to swears the water pump bearing is where the noise is from and that is also why the fan pulley has splay as well....I guess my question is does the fan pulley have anything to do with the water pump?

The fan isnt driven off the water pump. Its attached to the 'fan bracket' and thats most likely what is causing the noise. Isuzu lists 2 different ones depending on the month it was made.

BRACKET; FAN 8-97148-675-1 08-1997 to 07-1999
BRACKET; FAN 8-97231-718-0 08-1999 and LATER

If you go to myisuzuparts.com and do a search for one of those part numbers you can see an exploded diagram of what it looks like.

after discussing it with you guys and my dad, who has changed a timing belt on a couple of troopers...(every person in my family has a troopper!), I asked the mechanic I showed my car to why he thinks it is the water pump...and I also explained to him that the fan pulley and the water pump do not have anything to do with eachother...he got really bent out of shape...so I did not let him anywhere near my truck!!

Took the belt off and it turns out that the idler pulley is really worn out...

Thanks for your help...the tech guys on this site are really awsome...

just goes to show you that you should question every thng that just doesn't add up... <img src="/forums/images/graemlins/nana.gif" alt="" /> <img src="/forums/images/graemlins/butwiggle.gif" alt="" />

well got that fixed and now the fan pulley is making the same "rocking" noise. It does not sound the same as when the idler pulley and tensioner pulley were making noise though....not really sure if it is coming from the engine or what...when I rev it it disappears....

what online source do you guys use for parts....I think Ineed a fan bracket, is the pulley part of the bracket assembly or is it different?

just playing devils advocate but have you tested your fan clutch? Try spinning it 6 full rotations or more in one direction is a bad thing. i recently had this happen to my rodeo. on startup it was an intermittent kind of grinding noise.

Not exactly online but I have used St. Charles Isuzu a couple of times and have had great service and very good pricing <img src="/forums/images/graemlins/cheers.gif" alt="" /> compared to local dealers. Contact Merlin @ 800-727-8066.

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And free shipping!!