Acceleration from 0-30 making a rumble sound...

Sime

Sime

Sime

Soldato
Joined
8 Nov 2006
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Basically I was out looknig for a new car to buy when I drove over a speed bump. The car made a really loud bang sound under the front end so in a panic I got out to have a check. Initially I thought it was a flatty and both the tyres were fine.

I got back in and started to drive off. When accelerating from 0-30ish with any sort of pressure added the car makes a really loud rumble sound (imaging the sound of when you drive over those rumble sections in the country side for sheep) as soon as I go over 30 mph the car is fine and doesnt sound or act any differance. Brakes are fine, susspension is fine.

Anyone know what the problem might be?

Car is a 2000 MK4 Astra Coupe

Thanks everyone :(
 
Sounds to me like you've knocked the exhaust & it's touching the chassis/body at low revs or on initial torquing up.
 
It does sound like something has taken a knock and is now vibrating at low revs. I've seen a similar problem with one of my parents' cars, and that was because a mechanic had forgotten to re-attach an engine cover underneath the car properly.
 
Peter Diffey said:
Are you sure it just stops at 30? Because it seems to me like the only reason the noise is stopping is because you stop accelerating!
Click to expand...

nah it stops around the 30 mark when I have to change gear in 2nd...so basically in 3rd gear and above its generally ok then and accelerates just like normal.

The car itself seems to be driving ok like the steering doesnt shake or anything. Its just a very strong vibration and noise when acclerating. Im just trying to think what could have hit the underneath when I was going over the speed bump
 
Nope as it wouldn't be torquing the engine up against the drive wheels creating the engine movement that will make the exhaust hit the chassis/wherever.
I'd look underneath & check that all the rubber holders are on for starters then secondly I would get somebody else to bite the clutch up whilst I watched the engine to see how much movement there is, May be an engine mounting is shot which is causing excessive movement, Doubtful though I'd bet it was the Exhaust fouling somewhere.
 
Going to Kiwk-Fit in the mornin so they can put it on the lift and I can see exactally whats going on under there :p
 
"It's hard to steer" along with rumbling is usually a badly worn CV joint/driveshaft, if you wind the window down can you hear any clicking if you drive slowly in a circle on full lock?
 
Well! Problem solved!

Basically went into Kwik Fit this morning. Waited 40mins for him to look under my car, say "hmmm, that all looks fine..."

He then procceded to take the car out to have a drive around and see if he could pin point the sound. He went out, ragged it came back in and said "Its gone...".

Hmmmm, fair enough! Pumped up my tyres and I was on my way! Low and behond, the sound has gone!!!! WTF!?!?
 
He probably got out half way round the test drive & stuck his foot on the tail pipe bending the exhaust down & off the chassis. :p
 
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