Hi, my car has a noise when its running and cold...to me..its best described like broken marbles..its a loose clacking kinda sound...I am guessing water pump...but its not leaking or anything..can anyone back up my thoery or perhaps offer an alternate cause ? Kinda hard to get at this stuff on a 3.2..Id like to go in prepared..thx
It depends on the car, but I have heard the sound he described enough times that I would say it could be his water pump. A lot of water pumps, when they go bad, do have a higher pitched noise that could be described as a quasi-rattle. Normally, by this time, they are leaking noticeably.
Since his isn't leaking, I'm going to guess it is the compressor for the air conditioning. It may need some PAG oil in it.
It might not be the water pump. If you are handy with tools, remove your serpentine belt and start the engine. If the sound goes away, it's either the tension pulley, power steering pump or alternator. If the sound is still there, remove the AC belt. The AC clutch or tension pulley could be bad. Restart engine. If the noise is still there, it is either the water pump or tensioner pulley. If you have to change your water pump, do it right and change the belt, pulley and maybe the tensioner since everything is right there when you open her up. Also, an automotive stethescope helps find sources of noise.
Usually when a water pump goes it leaks out the 'weep' hole due to the seal going bad. I've never heard one go that gets real noisy but I won't say it's not possible. I would go with TTrepid's recommendation and try to narrow it down.
Does the noise change with engine rpm? Have you tried turning a/c on and off to see if it changes?