Removing Background Sound?

[brispuss]

I have an audio clip of an engine running at around idle speed. The problem is that there seems to be some slight background rhythmic sound which I believe shouldn't be there.

The main engine sound seems OK, but there is a background noise (sounds a bit like shwar shwar shwar shwar etc) which is distracting and shouldn't be there, or at least not noticeable.

How to remove the background sound from the enclosed audio clip as far as possible without effecting the main engine sound using an audio editor?

[cholla]

Sounds like the bearing in something.
The alternator for example.
Remove the drive belts or serpentine belt.
Then start the engine & run short term see if the noise disappears.
If it does then it is something the drive belts are running.
If not it is some other bearing or bushing noise.
For example if your radiator is cooled with electric fans.
If you have a manual shift transmission it could be the throwout bearing.
Too many bearings can make a similar noise to make an online diagnosis.

[brispuss]

Thanks for the comments.

Sorry, but I didn't make myself clear enough. I'm wanting to remove the background sound from this audio clip using an audio editor.

I've amended my first post to make it clearer.

[davexnet]

Do you mean this sound in the low frequencies?

[brispuss]

No.

If you play back my engine.wav, and especially when you loop the playback, you can hear a sort of low to mid frequency sound like shwaa shwaa shwaa behind the engine idling sound. That shwaa sound is the sound I would like to remove from engine.wav.