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MG Midget and Sprite Technical - Grinding noise

Mild grinding noise coming from the front of the engine somewhere. Reasonable to assume water pump or alternator - bearings most likely. Belt is new and correctly tensioned. Tried the WD40 to see if it goes away to determione which - no joy. Any other quick way to detemine the root cause would be most appreciated. - without removing them!
Oggers

Does the noise go away if you take the belt off?

That would likely prove alternator or water pump, but not which.
Dave O'Neill 2

Dave

That's the issue! Don't fancy removing the water pump if I can help it.
Oggers

Is this the non A-series engine we're talking about?
Dave O'Neill 2

You could spray some thin oil on one of them to see if it stops. Probably easiest to do the alternator. Mine started making a noise so I squirted some oil down the back of the pulley and it stopped. It came back after a while so I kept oiling it (only a couple of drops!) every time it did it and it seems to have stopped for the moment.

I'm not saying it will fix it but it might help diagnose which one it is.

Or maybe just removing the belt as Dave suggests and spin them by hand - might get an idea of which sounds worse.
John Payne

Try using a long screwdriver as a listening stick. Place the pointy end on the suspect item, close to the bearing, and place your ear on the handle and listen. You may be able to tell where the grinding noise is coming from. Of course, keep clothing, neck ties and hair etc well away from moving parts while doing this!
Jonathan Severn

Jonathan has the right idea. Have a quick search on amazon and you can get a mechanics stethoscope for about a fiver.
I have two - they're an absolute godsend.
Greybeard

I've just bought a cheap mechanics stethoscope. Brilliant. Wish I had bought it years ago. On my fuel injected MGB V8 I can listen to each individual injector firing. Amazing.
Mike Howlett

Alternators tend to squeak / squeal rather than grind so my money is on the pump - loose bearing can allow the impeller to touch the cylinder or block wall in some cases.
Chris at Octarine Services

This thread was discussed between 25/06/2018 and 26/06/2018

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