Silent unit: purpose, service life and price

The bushings in your vehicle reduce vibration and shock and therefore contribute to increased driving comfort. They are located in different places of the car: exhaust, engine, suspension, etc. Their elasticity helps to reduce friction between two parts of the car.

🚗 What is a silentblock?

Word silent block was actually the registered name of the Paulstra company but has now become public domain.

A silent block (or cylinder block) is a part of your car made of rubber or polyurethane. Its main role is to make your driving more enjoyable and smoother by reducing noise, vibration and shock between different parts of the car.

Thus, the role of the silentblock is tolink between two parts of the car. Between these two bodies, it acts as a shock absorber due to its elasticity.

?? What are the types of silent blocks?

The car has several silent blocks, in different places where it is necessary to connect two parts by reducing the jolts between them. This is especially true for the suspension, exhaust system, but also your car's engine.

Quiet engine block

The role of the engine bush is to reduce vibrations generated by the engine / clutch / gearbox triple. There are several types of engine silentblock:

• The most common silent block, in which an elastic block is inserted between the two metal parts connecting the frame and the engine.
• Hydraulic silent block it works with oil and sometimes can even be electronically controlled.
• Anti-rollover silentblock : it can be in the form of a connecting rod surrounded by an elastic block on both sides, or a cylinder with a rigid part in the center that connects the two ends. The elastic part is connected to the frame or motor, and the metal support is opposite.
• Balanced silent block : Works for compression. To do this, it is positioned horizontally so that it can support the weight of the engine, which is pointing downwards. Thus, there are two silent blocks, one on the side of the distributor and the other on the opposite side. To these two silent blocks, you must add a third one, located in the middle or at the rear of the engine. The role of this third silent block is to maintain balance and prevent tipping.

Silent outlet block

Le silent exhaust unit serves to reinforce the exhaust pipe, keeping it on the chassis and thus avoiding vibrations. Exhaust bushings must be resistant to heat, which can sometimes go up to 220 ° C.

🗓️ When to change the silent block?

The durability of silent blocks depends on where they are located, on your driving style and on the stresses that can damage them. They are usually designed for a long service life. more than 100 kilometers... It is generally recommended to check the bushings when your vehicle has driven approximately 80 kilometers and then annually during a major overhaul.

However, if you see certain symptoms, such as vibrations or jerks while driving, or even jumps in speed, it's time to change the bushings and head to the nearest garage.

However, the symptoms of a faulty silent block depend on where the part is located. If it is a suspension bush, in particular, you will notice that the car has a tendency to pull to the side and that its handling is impaired.

?? How much does it cost to replace a faulty silent block?

The silent block is not a very expensive part. You will find some parts of 10€, even if the price of some silent blocks can reach up to one hundred euros. To this price you have to add the cost of labor, but the replacement of the silent block is a relatively quick intervention.

If you would like a more accurate price quote based on your car model, use our online garage comparator and compare dozens of garages near you at the best price and based on reviews from other motorists.