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Intermittent metallic noise
Posted: Thu Jul 25, 2013 3:32 am
by bizz
Hi all,
I have a worrying noise coming from the engine bay, an almost metallic grinding noise. I don't think it's rod knock, as it comes and goes regardless of engine temp.
Reading through old posts, sounds like it could be the water pump. Anybody experienced an intermittent grinding sound with failed water pumps, or does the sound hang around?
Cheers
Posted: Thu Jul 25, 2013 9:58 am
by Mike W.
My BMW water pump failures have all been leakers, not bearing failure. Might be the alt bearings too. Pop the belt off and see what they feel like. Do you have A/C? It could be that bearing too.
Posted: Thu Jul 25, 2013 7:40 pm
by bizz
Thanks,
I will pull the belt and test the bearings.
Can I run the engine for a short time with the water pump detached to see if the noise disappears? or is this generally a bad idea..
Posted: Thu Jul 25, 2013 9:35 pm
by GripGreg
I'll bet that if you get a mechanics stethoscope, it'll make a differance.
From maybe NAPA, or Pep Boys? Even Autozone, maybe.
It should pinpoint any noise. Mine works well. Now if I could just find it.
Good luck,,,,Greg
Ps,,,Here's another ole skool trick: place a longer screwdriver metal tip on the part in question & place the plastic handle to your ear. Sound travels.
A wooden handle my not conduct enough sound?
I say longer 'cause you don't have to bend too much. A sort one will work.
Posted: Thu Jul 25, 2013 11:12 pm
by Falkenberg
My '76 suffers from some alternator noise. It diminishes when I spray lots of WD40 in there, that is how I diagnosed..
Posted: Thu Jul 25, 2013 11:47 pm
by Mike W.
bizz wrote:Thanks,
I will pull the belt and test the bearings.
Can I run the engine for a short time with the water pump detached to see if the noise disappears? or is this generally a bad idea..
Not long, but a minute or two will be fine. Just make sure you put it right back on so you don't forget about it and drive away.
Posted: Fri Jul 26, 2013 8:30 pm
by Troy
I had an A/C clutch fail that way. It made a low grinding sound. I was on my way from MA to CO in '83 and had to cut the belt off. Had it fixed in San Antonio when the voltage regulator decided to quit on me too.
Posted: Sat Jul 27, 2013 1:16 am
by bizz
Solved! Loose alternator bolt was the culprit. How embarrassing...
Posted: Sat Jul 27, 2013 10:05 am
by GripGreg
No, No! Nothing wrong with solving the problem!
And, it was cheap too!
