The car gets old quickly. The filling of his interior is deteriorating even faster - from seat mechanisms, their upholstery, door and ceiling trim elements to various keys, buttons, plastic levers, handles. All this, to use formal terminology, wears out: driving a car, even on quite decent roads, begins to be accompanied by extraneous noise. The motorist hears squeaks, knocks and even grunts. What is the root cause of the sad metamorphosis? It seems that the possibility of the transformation of a car into a mobile noise orchestra, first of all, is determined by the culture of its design - what is called a school. But schools, as we all understand, are different.
At the same time, the transition of the car to this state can be accelerated (slow down) actions of the owner himself, and they, the owners, are also different! One car protects, monitors its every whim, the other treats it like an enemy captured.
But back to the design school. Removing the upholstery of the old door - "Saab", for example, - you will see all kinds of levers, rods, cables, etc. The details are flimsy, and they are fixed "Just" or "very simple"! It seems that the designer took care that the mechanics did not rattle on the day the car was sold.
One of the most common causes of extraneous noise in the cabin is the loosening of the connected parts due to their vibrational wear. In moving units, wear from the relative movement of parts is added to this.
Why, for example, "itching" any decorative panel, if it is tightly, fixedly connected to the base of the body or door? In fact, both the panel and the base vibrate, and often in different ways. This means that vibrational movements occur in their contact, which wear out the material. Further - a vicious circle: more vibration - more wear, stronger noise.
Evidence of vibrational wear of some plastic parts may be characteristic dust at the points of contact, traces of mutual abrasion. Eliminate vibration movements - wear will disappear.
Vibratory movements of parts, such as the interior decorative panels of doors, can often be minimized with the help of additional fasteners, such as self-tapping screws. It happens that they do it differently: a gasket made of foam rubber, sponge rubber, latex is installed between the panel and the door - materials that dampen vibration well.
How to deal with this has already been said. There is another way, tested by experienced motorists: the panel on the inside is pasted over with an additional layer of sound insulation - even with an old blanket. It is a laborious task, but the one who decides on it will be rewarded: the knocks are almost completely silenced.
In general, when you have to fight with the noise caused by the vibration of any panel, you should not treat this as a deliberately simple, easy matter, especially if the vibration of a rigid panel is not damped by anything (i.e. not extinguished). Here, even additionally strengthening it with self-tapping screws, you can not achieve the desired results - stopping "itch" at one speed, the panel can make an even more obnoxious voice at another. The use of soft pads usually gives a positive effect.
So many times mentioning the word "vibration", it’s not a sin to say which ones we are talking about. Unfortunately, various parts in the cabin, with different sizes, weights, stiffness, etc., have corresponding "favorite" vibration frequencies to which they readily respond "itching", tapping, rustling, etc. The vibrations themselves are caused by the operation of the engine, gearbox, transmission, the rotation of the wheels, and finally, the roughness of the road. The frequency spectrum is so rich that any detail, given illegal freedom to vibrate, "my" find the frequency.
This freedom has to be limited in one way or another. Does a switch vibrate? Glue a thin strip of foam rubber to it or press it with an additional spring. Is the rod rattling inside the door? They support it with a pad of the same foam rubber... or lightly tie it with an elastic band to the door frame.
Looking under the dashboard, you will see a picture of complete chaos: wiring harnesses and individual wires, numerous electrical connectors, cables. Appliances and switches nearby. There is also a collection of ownerless bolts-nuts that got here during the assembly of the car. All this rattles, rattles, especially in winter, when the wire harnesses are hard as a stick from frost, and just like it, they hit the details of the structure. That is why many motorists literally fill the space under the instrument panel with foam rubber or latex.
By the way, amazing results are obtained by additional sound insulation of the engine compartment and at the same time the space under the dashboard. This is done with a piece of foam glued to cardboard, which is laid from the pedals up to the edge "torpedo". It is clear that such "muffler" must be securely fastened and not interfere with control.
Noise in the car interior is largely due to the properties of the materials used. Unfortunately, parts are often made of plastic, which is not resistant to wear, brittle, etc. Naturally, "loosening" a node assembled from them can happen very soon.
If the parts work at even slightly elevated temperatures, it is important that they do not warp or shrink. In fact, we see this process in any of our cars.
A special kind of noise is squeaks. The causes of a creak can be very different, but they are all united by the root cause - the movement of one part relative to another in a pressed state and the work of friction forces. Why not, for example, creak the edge of the dashboard if the door is pressed tightly against it when closed? The whole body on bumps in the road "breathes", the parts move mutually, causing a creak. It will disappear if you manage to eliminate "illegal" contact. Most often, this loosens the mounting screws and shifts the dashboard as needed.
The seat springs at the points of contact with the frame have "anti-creak" coating. But its layer is rather fragile, it wears out. And here is a script for you. You can eliminate it in different ways. One puts a plastic tube on the spring, the other winds the insulating tape, the third lubricates with graphite grease. All methods are rather frivolous - these measures do not last long.
Squeaking in swivel joints is best eliminated precisely by the periodic use of graphite grease.
Another kind of squeak is an extremely unpleasant sound that occurs when the heater fan is turned on, when the motor shaft rotates in the stator bushings without lubrication. There is only one way out - disassembling the engine, cleaning it from dirt and replenishing the lubricant.
As you can see, there are two ways to get rid of creaking - either eliminate the mutual movement of tightly pressed parts, or lubricate the rubbing parts.