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Discussion Starter #1
Hey all,

I recently got myself a naturally aspirated '86 300zx auto trans, and have been doing quite a bit of repair work since then. Most recently was a new radiator and timing belt job, which included a new thermostat, water pump, cam seals, tensioner, the works. After getting it all back together and starting it up, there was a loud whine coming from the front of the engine. It increases in pitch and volume with the revs, and the "stethoscope method" (Metal rod pressed against various pumps and whatnot while listening intently to the other end) determined it was the water pump doing the whining.

Near as I can tell I'd gotten it back exactly the way it came apart. The tension on the power steering, AC, and alternator belts is right where it should be, at least I think so.

Any ideas? I greatly appreciate any help anyone can offer, I'm fresh out of ideas. Thanks!
 

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try backing the belt off some... might be too tight. nother reason why i like timing chains.. there's no way to put it on too loose. so don't just try what i say.
i'd take it to a trusted shop, for a second opinion.

or... it's a piece of crap aftermarket.
or... you got a defaulty one that has bad bearings.

don't know how yours works..
but mine is just a paddle wheel connected to a pully and flange that the fan attaches too...
the belt turns the pully, the pully turns the paddle wheels... the whine could come from the fan clutch.

how'd you put a stethascope on it when the fan was so close?
 

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Discussion Starter #3
Thanks for the response.

I actually used just a steel rod that we had laying around, and a lot of caution. I don't have a proper stethascope. The water pump was the only pump that gave me the same whine back through the rod. Everything else was quiet.

I think I'm going to take it into our friendly local Greg's Japanese Auto and see what Greg can make of it. One would hope the water pump wasn't defective, it's a genuine Nissan part purchased from a dealership.

Mine works the same way, and the fan clutch had occured to me too, but it only really goes on one way. Can't imagine that it's even possible to get it on backwards. Since the noise only started once we got it back together I assumed that the fan clutch was still good. However this would not be the first time I've been wrong.
 

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I work for a Nissan supplier. I've seen how service parts are handled. they don't go thru the "normal" production process. I didn't say it was likely, just possible. Most of the service parts on cars this old have been on a shelf somewhere for years. .. .
 

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oh yeah, definetly..

for a month or so, i worked in a nissan parts department...

i still have a shitload of outdated parts that they were just throwing away cuz they were so old..

i was lucky enough to be there for inventory while also cleaning out the gutters so to speak.
 

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Discussion Starter #9
Update:

So the whine has gotten quieter, and I'm still having no trouble with cooling, even with extensive driving (100 mile journeys). I have put off taking it into a garage to have a professional poke around underneath, I can't bring myself to pay someone else to fix it, and I lack the extra cash to pay for a diagnosis. Is there anything I could do to narrow down what's whining short of replacing the water pump? I don't have the time or money to buy a new one and tear back into it right now. From what I can gather, if it is the water pump bearing I've got quite a while before things will start going bad quickly. I also understand that if it is the bearing, the noise will change to more of a knocking before it gives out all together. Is this true?
 
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