Odd thumping/knocking noise while idle

MKOO

MEMBER
2002 SUZUKI SWIFT
1.0L
3 CYL
2WD
MANUAL
49,000 MILES

Hi, recently my vehicle has developed an odd thumping/knocking noise, almost reminds me of metal hitting against metal lightly.

Dealership has verified that its nothing motor related but no real reason has been found for it.

This noise occurs only when motor is warm and rpm's are at idle level, which is something along the lines of 750-850 rpm's.

Above mentioned sound does not occur at other rpm ranges at all.

I suspect it could be some sort of engine mount, I have inspected one of the mounts and it doesn't seem worn. Other two mounts require car lifting so I haven't done that yet.

Do you have any suggestions where to start looking next? Idle rpm's under 900 bringing the noise should hint to something but I cant think of anything at all. This noise that comes most likely under the hood can be heard best while being inside the car. It cannot be heard as intensely while popping the hood up and trying to listen the engine noises in front of the car.

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1 Reply

JACOBANDNICKOLAS

MECHANIC
109,724 POSTS

Hi,

For some reason, I am not showing this model in 2002. In 2001 it shows a 1.3L engine. However, I will try to help.

I did hear the sound. It seems to be louder at the front of the engine. What I would do is remove the accessory drive belt the turns the alternator, power steering pump and so on. Once it is off, start the engine (only for a few seconds) to see if the noise is gone. If it is, then I would start checking each of the accessories to see if one appears to have a bad bearing.

Here is a link that explains different sounds that indicate engine issues. However, you mentioned the shop said the engine wasn't making the noise. Also, as far as a motor mount, if the engine is running smooth and not shaking under the hood, chances are it isn't a mount.

https://www.2carpros.com/articles/engine-noises

Let me know what you find. Also, let me know if you have other questions.

Take care,
Joe