Grinding Noise in Engine

I drive a 2000 Cherokee Sport and recently I have started hearing a noise coming from my engine that sounds like rocks in a tumbler. It started about two weeks ago and I checked fluids and added what was low. It's back now and I am not sure where it is coming from. I don't see any visible leaks coming from the engine.

Has anyone had a similar problem or have any suggestions to offer?

How many miles and can you locate the source of the sound more precisely?

185,000 miles Inline 6. I wish I could, but it's hard to tell. It sounds like its coming somewhere from the center back, but I can't tell if it's coming from underneath. Someone said it could be a drive shaft problem or something related.

I did check the pulleys and belts and they all seem to be working fine. I thought it could be that since the noise occurs when the car is simply idling.

Thanks for the response!

"Rocks in a tumbler" made me think of a water pump going bad. There's also an issue (if yours is an automatic) with the bolts on the flex plate getting loose over time.

The water pump would be making noise up front.

So it makes the noise when idling and not moving? Then it's not the drive shaft.

Yeah, it makes the noise as soon as it cranks. It seems to be tied to acceleration because as the car speeds up so does the noise. Does that make sense? it's like the rocks are tumbling faster.

Interesting that you mentioned the water pump. I just had tires put on and the service guy told me my water pump was going bad. Is there something I can do to check this out?

A bad water pump sounds like water going over a bunch of pebbles in a glass jar. If that's the sound you are hearing, I'd suggest getting the new water pump. Things to look for are the noise, plus any weeping -- there's a hole in the water pump under the shaft that will start to leak when the bearings go bad. Not much at first, just might look a little damp, but more as time goes on.

A bad water pump sounds like water going over a bunch of pebbles in a glass jar. If that's the sound you are hearing, I'd suggest getting the new water pump. Things to look for are the noise, plus any weeping -- there's a hole in the water pump under the shaft that will start to leak when the bearings go bad. Not much at first, just might look a little damp, but more as time goes on.

You were right, it's definitely a water pump. I'm going to attempt to replace it this weekend, do you have any tips to pass along?

Nope, should be pretty straightforward.