Knock from engine

[MakaveliX]

Hi guys
Did some spark plugs yesterday, and been for a few drives since and everything was fine
Car is a 2002 Mercedes with 33K on the clock

Just come back and seems to be making an odd knocking noise, I think it's coming from the alternator belt as that is where the sound is loudest
No error codes, car runs fine.

https://www.youtube.com/shorts/fbTb0HhvS5c

Any ideas ?

Edited by MakaveliX on Friday 5th July 11:19

Edited by MakaveliX on Friday 5th July 11:32

[stevieturbo]

then remove the belt and try.

[MakaveliX]

Removed belt, sound stopped.

Seems as though the water pump is the culprit as it is wobbling around slightly when I try to move by hand.


How on earth can a car with 33K miles on it, have a water pump going bad.

Only solution is to replace the water pump which looks a right pain.


Coolant levels are fine, and the car runs at a normal temperature

Edited by MakaveliX on Friday 19th July 20:02

[rallye101]

MakaveliX said:

Removed belt, sound stopped.

Seems as though the water pump is the culprit as it is wobbling around slightly when I try to move by hand.


How on earth can a car with 33K miles on it, have a water pump going bad.

Only solution is to replace the water pump which looks a right pain.


Coolant levels are fine, and the car runs at a normal temperature

Edited by MakaveliX on Friday 19th July 20:02

It's 22years old!

[MakaveliX]

rallye101 said:

It's 22years old!

I know. But if the part has barely been used, I wouldn't expect it to go so soon.

[Acorn1]

MakaveliX said:

I know. But if the part has barely been used, I wouldn't expect it to go so soon.

Gaskets and sealed bearings deteriorate over time, much like us

[E-bmw]

Every time it sits for extended periods with tension on one position the bearing will be taking the tension in that one place rather than all round its bearing faces, this may explain it.

[LordLoveLength]

Acorn1 said:

MakaveliX said:

I know. But if the part has barely been used, I wouldn't expect it to go so soon.

Gaskets and sealed bearings deteriorate over time, much like us

Also antifreeze deteriorates with age - the corrosion inhibitors become less effective and things start furring up or rusting. Has it ever been changed?

[MakaveliX]

No idea on the coolant being changed. It looks healthy and the engine runs at operating temperature properly.

I will be replacing the idler pulley first, then doing a coolant change and possibly water pump too at a later date.

[Acorn1]

MakaveliX said:

No idea on the coolant being changed. It looks healthy and the engine runs at operating temperature properly.

I will be replacing the idler pulley first, then doing a coolant change and possibly water pump too at a later date.

I would change all of them when you change the pump. Otherwise your just making more work for yourself.

Easy test, put a socket extension on the pump and to your ear, you will hear if the bearing is U/S

[richhead]

also check the belt, if it has cracks in the teeth/ridges, they can make quite a noise.