TheNoble

Hey guys,

I've done some research and cannot seem to find anything definitive so I had to ask.

More often than not upon acceleration from a stop there is a deep/heavy sounding clunk noise that feels and sounds like it comes from the bottom of the car. Any idea what it could be?

Some other forums were saying shocks might be going bad? How would that make a clunk noise on acceleration?

It's not anything in the trunk that's hitting walls on acceleration or anything like that.

Thanks!

DanielFD

It sounds like its the front suspension, sadly i cant remember what the part is called, But its the part that holds the front control arms to the chassis. They are rubber parts and there are 4 of them for the 4 control arms in our cars. They are cheap parts about 30-40$ each but installing them will need special tools to "plug" them into the control arms.

DanielFD

Control Arms Bushings! Just remembered!

Yidney

Inspect your engine and tranny mounts.

megacrazy

It's very easy to inspect the front suspension. Just look at the bushings and use a pry bar to move things around. If it's that, you should be able to replicate the noise.

However, from what you're describing it sounds like the transmission mount...or engine mounts.

TheNoble

This is the first I've heard that it could be the engine or transmission mounts. Is that normal and should I be concerned about it immediately? What exactly about them would cause the clunk?

I've been driving the car for awhile now and so far nothing serious has happened, it's just annoying. I also feel like there's loss of power but that's probably just me believing that's probably just psychological.

megacrazy

Well it's pretty simple. The car starts moving, weight shifts, the mounts are bad...you get noise because the components are not supported properly. Look up videos to see what bad engine mounts look like. The transmission mount is easy to replace and cheap.

If it was suspension components it would be more road related...in other words...it would do it when turning...or going over bumps etc....so keep your ears open and poke around. Noises are sometimes hard to diagnose.

DanielFD

You guys are correct about the mounts if they are bad or incorrectly installed, but if they are the culprit you should be feeling vibration in the cabin and a louder engine rumble from your dash area when your in the car. But control arm bushings also cause this exact sound. Twice in my c230 and my clk the culrpit was bushings. When they get worn down and the front wheels switch fast from stopping motion (or stopped) to acceleration movement and the opposite there is pressure put on the bushings and causes that one clunk sound. Visual Inspection of the bushings will be easy just look to see of they are worn out or cracked.

TheNoble

That's why I'm suspect of the engine and tranny mounts. I don't really have abnormal amounts of rumble in the cabin.

Once I get a change to lift the car and look at the bushings-which might be at the end of the summer - I'll make sure those bushings aren't dead

Yidney

A bad motor or tranny mount won't necessarily cause a rumble. Things shift when under stress - like starting from a stop, then settle down when the stress goes down when the car is moving. I once had a V8 with a completely torn motor mount and the only symptom was sort of a clunk at start, and when I pressed the gas with the hood open I could watch the engine lift up and try to roll over on its side from the initial torque.

lowpost

my vote: tranny.