Happy New Year to all i drive a 99 volvo s70 non turbo and at idle and at red light i get a buzzing sound or vibration sound can the engine mounts make this sound or should i be looking at the strut mount plate and spring seats i know the sound is behind the drivers side tire

i hear a pooping sound when i back up

Inspect the flex joint of your exhaust manifold.
Maybe it's a bearing noise? You have T-belt and S-belt idler pulleys and
water pump bearings, all in back of the passenger side wheel well.
Take a video and share the sound with us at different RPM.

Bill

ok ill try to make a video when buzzing sound happens

Does it buzz when it is not in gear? Stopping at a light in gear loads the engine a bit and can cause small vibrations.

I agree with the other poster, it is probably a heat shield somewhere.

Do you service your own car?

You could have it checked at your next service or try see where the sound comes from by looking under the car.

One way to locate a noise is to take a 4 or 5 foot piece of hose (like heater hose or garden hose) and hold it to your ear, move the other end around to find the source of the noise.

I change the hoses to my washing machine every 3 or 4 years and keep the old ones for circumstances like this.

it buzzes when its in gear and when its not in gear

Hi,

Just from the word “buzzing” usually correlates to a heat shield, in my experience.
It’s on an exhaust manifold or are near the catalytic converter or before it.

The FWD cars also have heat shielding panels on the body or firewall of the car too.
When I first saw them on the 850s.
I called them turkey roasting pans and adding on that it was really a sign of an “all out” investment in manufacturing of the car. (:-)
I did this to upset the salesman’s responses and choreography.

The salesman got it quickly that I wasn’t going to buy a car.
I was there for my entertainment while my wife went mall shopping.
Now they just get parked with dealer MSRP stickers.
It’s good as the hoods are closed as all you see today is plastic covering up vital questions.
How did they get all that in there?
Where is that buzzing sound?
I see cars going down the road with pieces hanging down under the car.
Missing some replacement clips for sure, as they don’t grow on a tree in the shops!

What’s going to happen to that wipers on headlights? Especially, if they keep using plastic headlights?
What a folly!
I guess they could still use them, if an aerodynamic shape would allowed it?
Jet fighters don’t have any but they polish the canopies.
Windshields get it bad enough already, but comprehensive insurance policies covers those
The outrageous expensive headlights are not?
The sunshine and a sandy dirt blasting will make sure you replace those lens anyway.
Now that’s a “buzz kill” that the illustrious DOT stuck consumers with.

(:-)
Have a nice New Year with more entertainment to come!

Phil