Help with Engine Noise Diagnosis

[hot_sd]

Would appreciate some input on this. Recently the engine has started doing this. The best I can describe it is a "chugging" sound or a very pronouced idle sound. It can only be heard at idle when in an enclosed area like a garage. It gets worse when put under load - turning light on or putting it into gear. The rate changes with rpm so it is engine related I guess. It appears to be coming either the intake manifold area or around the accessories. From what I can hear it sounds like part of the engine rather than from a secondary item like a mount.

The eninge runs fine and no difference in performance during normal driving. No change in sound when hot or cold. Everything else working fine.

Any ideas?

[spy1309]

Sometimes the water pump bearing or alternator bearing can make sounds like the one you describe.

[hot_sd]

Thanks for the reply - that's what I was afraid of - I also spotted a few drops of coolant coming from the water pump area. Don't look forward to pulling out all the belts again to replace it if that's what it is. Wish I had put a new water pump in when I put in the new belts.

[hot_sd]

Turned out to be the alternator bearings - good advice - thanks