Knocking Noise Diagnosis Help
Discussion
About a month after MOT-ing our family estate last year we had a rattling and knocking noise coming from underneath. Our local garage took a look and told us the back box was broken and causing the noises.
FFWD to this year. We didn't bother repairing the car as we thought we'd wait for the box to fall off and thus save a few pennies whilst we waited. MOT time is coming and we'd like to sell up. I checked the back box today as it was still hanging in there. I find out that the clamp is warped and not holding the flanges together properly between the two pieces of exhaust. Easy repair, clean up and new clamp, job done.
So now the rattle has disappeared but we're now left with a knocking noise that has nothing to do with the exhaust as I've checked it thoroughly. It occurs when travelling at any speed over un-even surfaces and sounds to me at least like something jumping/ knocking up and down between two parallel surfaces. The knocking is not present when at a standstill, pulling away, under braking or just from turning the wheel.
My immediate thought is that it's the top mount / bearing on the driver's side, or the top engine mount again on the driver's side but I've got dodgy hearing on my left side and I can't really trust what direction the noise may be coming from. It could I suppose be the arb bushes or something similar but I don't think it's anything outside of those three areas because the steering has been fine the past year and there's no uneven tyre wear.
The engine mount looks easiest to do and is the cheapest but I'm not convinced it could be this so am going to leave this till last. So before I invest in some spring compressors and top mount/ bearing can anyone suggest anything that I may not have considered?
All replies appreciated.
FFWD to this year. We didn't bother repairing the car as we thought we'd wait for the box to fall off and thus save a few pennies whilst we waited. MOT time is coming and we'd like to sell up. I checked the back box today as it was still hanging in there. I find out that the clamp is warped and not holding the flanges together properly between the two pieces of exhaust. Easy repair, clean up and new clamp, job done.
So now the rattle has disappeared but we're now left with a knocking noise that has nothing to do with the exhaust as I've checked it thoroughly. It occurs when travelling at any speed over un-even surfaces and sounds to me at least like something jumping/ knocking up and down between two parallel surfaces. The knocking is not present when at a standstill, pulling away, under braking or just from turning the wheel.
My immediate thought is that it's the top mount / bearing on the driver's side, or the top engine mount again on the driver's side but I've got dodgy hearing on my left side and I can't really trust what direction the noise may be coming from. It could I suppose be the arb bushes or something similar but I don't think it's anything outside of those three areas because the steering has been fine the past year and there's no uneven tyre wear.
The engine mount looks easiest to do and is the cheapest but I'm not convinced it could be this so am going to leave this till last. So before I invest in some spring compressors and top mount/ bearing can anyone suggest anything that I may not have considered?
All replies appreciated.
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