hollow knocking sound when driving over bumps
 

Hey all, Im new to this forum. Im the original owner of a 2007 Mazda 3i. I love the car and since its finally paid off, I plan to drive it until the day it dies. Im slightly obsessive about the vehicle's maintenance, but only because I hope to get at least another 100K out of the vehicle. The car currently has 69K on the odometer. I will come out and say that I know very little about cars! But Im here to learn more.

Recently, I have started hearing a hollow knocking noise come from the front end when I drive over almost anything... manhole covers, large cracks in the road ETC... The car is driving fine and there is no shimmy in the steering or engine vibrations. The knocking sound seems to be over the front tires. Its starting to become annoying.

Any ideas on what this could be?

The car is driven mostly in Jersey City, North Jersey and NYC where the roads are incredibly poor. Im sure since moving here two years ago the suspension has taken a beating. I purchased the car in Las Vegas where the roadways are smooth as glass.

My intitial instinct is that I have a problem with the suspension.

Also, if anyone can point out what sort of maintenance issue I should be watching out for as the car hits 70-75K I'd appreciate input. Does anyone know how long my clutch will last driving in city traffic?

So far the car has been a dream. When I orginally purchased it back in 07 I had an issue with the AC and then another problem with the brakes a year later, but since then it has been repair free. I had a full service tune up done when the car hit 65K by a mazda dealer and they replaced spark plugs a belt or two, but they said it did not need anything else. Just trying to stay ahead of of the curve here!

check the end links.

it could be you weel baring thats what was rong with mine and i sounds like to same issue i had

first thing to check is the passenger motor mount. It's located between the engine and the coolant resevoir and is easily visible..... big silver and black thing connecting the engine to the car. The stock mounts tend to not fare well in the long run. You're looking for signs that the oil inside the mount has leaked out (dark stain around the mount or below it), signs of drying/cracking to the rubber, or of complete breakage. Even if it's completely failed the engine isn't going to fall out of the car, but it will have several more inches of travel and can thunk up and down.

If it is your PMM you can replace it for about $100 for the OEM one.... not sure how much aftermarket ones go for. You just need a floor jack and some basic tools. Two bolts, two nuts and swap it out.

Beyond that check out your suspension components. Shocks/struts should be replaced every 50-75k miles. As was noted above also check the end links/bushings.

All that said I'm betting on the mount.