What happens when you step on the gas

What is rattling there? Noises in the car and their causes

Modern vehicles are surprisingly quiet at a moderate speed, which is why unusual noises inside the mobile pedestal are of course particularly noticeable. Before the "immobilization" is the localization of the noise source. A distinction is made between the noises of the drive, the chassis and noises that arise from the vibrations in the vehicle. The best way to "locate" a background noise is to clear out the vehicle. In addition, a co-driver helps - according to the motto "four ears hear more than two".

Can you hear the noise when the vehicle is stationary and the engine is running?

Then it cannot be related to the gearbox, the drive shafts or the non-driven axle. The brakes are eliminated as well as wind and road noise.

Does the noise increase or decrease with speed?

Then it is due to moving parts such as the crank drive, valve drive or the alternator. If it changes little, it is probably a vibration noise from a sheet metal or the exhaust system.

Can you only hear the noise when the car is rolling? Does it only happen when you step on the brakes?

Then there is imminent danger because there is obviously something wrong with the braking system. Pads worn out? Brake booster leaking? If, on the other hand, you only hear the noise under load, i.e. when accelerating, then either the gearbox or the drive is likely to have "tooth failure" or the motor is likely to have bearing damage.

Special case - and can only be heard when idling when the clutch is engaged

Here the torsion springs of the clutch pressure plate are usually slack and let the pressure plate rattle. If the noise occurs when the clutch is disengaged, the release bearing is likely to be defective. In both cases, a new clutch will soon be due, although the clutch as such is still working.

Does the noise only occur when the wheels are turned?

If there is a loud clacking noise, it is likely that a drive shaft joint is knocked out or is running dry (e.g. because a boot is leaking and the grease has disappeared). If there is a humming noise when cornering, the wheel bearing on the outside wheel is usually defective and needs to be replaced. The boundaries between noise sources from the engine and drive as well as the chassis are fluid. Some of the mysteries only occur under load or when cornering, but can be ascribed to the chassis or its suspension.

Basically, knocking and rattling noises from the chassis area are always caused by direct contact with moving parts (experts also speak of structure-borne noise). Constructively, this is achieved by "decoupling" the potential sound sources. In most cases this is done by storing the axle components in plastic. And this is where things get interesting: plastics age and wear out and can then no longer perform their function.

Does a noise occur when driving over bumps?

The source of the noise here could be the rubber mounts of the anti-roll bar or the wishbones. Sometimes the change is a matter of minutes, sometimes it becomes very time-consuming and expensive. If a clattering rattle with tire trampling is noticed on cobblestones (which does not mean extreme cobblestone stretches), the next trip should lead to a shock absorber test bench.

Does the exhaust make itself felt on bad roads?

If there are no suspension rubbers, the system starts to vibrate in such a way that the heavy damper pots hit the wagon curve from below. This is not only annoying, but in the long run it can break the pipes in the system. What this means for the budget does not need to be explained here.

Sources of noise in the interior of the vehicle are mostly easier to find, but not always easy to calm down.

Is it rattling out of the dashboard?

Badly laid cable harnesses or Bowden cables are usually the cause here, which hit the struts of the "hollow body" while driving. If you can get hold of the cables and cables in question, sheathing with foam strips will help. In previous years, the author of these lines cured an extreme case in a completely inaccessible part of the car with a good slosh of underbody protection. The stuff is so sticky that nothing moves in it and therefore can no longer rattle.

Plastic parts scraping together can be soothed with small, self-adhesive pieces of felt. Silicone spray also works wonders: when sprayed specifically at the chafing area, it causes less friction and therefore less noise for a while.

Does music come out of the speakers with whirring and booming noises?

This can happen because of poorly assembled speakers. This applies to self-installed boxes, but also to boxes that are placed in series. Here, too, foam strips and a qualitatively better fastening of the loudspeakers help.

And when the doors creak ...

Good old lubricating oil still helps against creaking and squeaking of the hinges of doors and hoods in 2018. It can come out of the spray bottle, but shouldn't get on brakes and upholstery.