Engine noise low level Hum

[madmac187 Junior Member Find all posts View Profile Close madmac187]

Hey all posted here a good few times hailing from good old cairns. I have noticed of late on certain mornings a low level hum on my 3.4. It seems it's like an electrical motor running. Generally there between 1-2500rpm. After that it revs out and can't be heard. It will only stay when running for 10 minutes then disappear. It's not constant or on all revs. I have been told by toyota it could be water pump or alternator. Has anyone any ideas. It isn't leaking or using water and starts first turn of the key

[Tukangbaso Lurker Find all posts View Profile Close Tukangbaso]

could be alternator

[madmac187 Junior Member Find all posts View Profile Close madmac187]

could be alternator

They said either or. That sounds to me a bit like bull. They should be easily differenciated. Also, took the car to another garage, nothing odd can be found with it and have been told that nothing is wrong with water pump as there is no sound and if a problem arises you would hear it. Im thinking maybe just a little dirt on belt or something. That or they are sorely mistaken with a problem and the sound of an air con unit.

[glen_ep Addicted PP Member Find all posts View Profile Close glen_ep]

Loose extractor covers? Leak somewhere in the exhaust? Pay attention to what kind of action makes the sound change, ie, speed, RPM, gear, air con, etc...

[madmac187 Junior Member Find all posts View Profile Close madmac187]

Loose extractor covers? Leak somewhere in the exhaust? Pay attention to what kind of action makes the sound change, ie, speed, RPM, gear, air con, etc...

It's coming from timing belt, only done 45k ago by toyota. Got new quote for all seals, tensioners, idlers and water pump for 800. So think I'm going to get it done soon as soon as it changes. Would anyone have any reservations about aftermarket Parts doing this work? Watergate with 2 year warranty. Opinions please?