The function of the insulation layer in the front compartment of the car
The underbody insulation layer of the car's front compartment (also known as the front hood insulation foam or engine compartment insulation foam) is an important component installed on the inner side of the engine hood and in the engine compartment area. Its function goes far beyond simple insulation. According to authoritative public information, its main functions can be summarized as follows:
Core Function
Insulation Protection
Prevent the high temperature (up to 200°C or more) from the engine from being transferred to the engine hood and the driver's cabin, preventing the paint on the engine hood from aging, changing color, or peeling off due to long-term high-temperature baking. The actual measurement shows that after installing the insulation foam, the surface temperature of the engine hood can be reduced from 180°C to below 120°C, and the aging speed of the car paint is reduced by about 3 times.
Reduce the increase in interior temperature caused by summer sunlight exposure, and some products can block up to 90% of the solar radiation heat.
Noise Reduction and Soundproofing
Absorb and block the mechanical noise generated by the engine operation, reduce the noise entering the vehicle, and improve the driving and riding quietness. The middle sound-absorbing foam layer has a sound absorption coefficient of 0.22–0.93 in the frequency range of 125Hz–4kHz.
Buffer the resonance between the engine hood and the engine, reducing abnormal noise during driving.
Enhance Energy Efficiency and Safety
Maintain the stable temperature of the engine compartment, improve the fuel atomization effect, reduce HC emissions by 23% during cold start, and CO emissions by 18%.
Reduce the load of the air conditioning compressor in summer, decrease the failure rate by 65%, and reduce the annual maintenance cost by approximately 800 yuan.
In winter, it helps improve the battery discharge efficiency, and the electric vehicle's winter range can increase by 12%.
Use flame-retardant materials (such as aluminum hydroxide), and when exposed to fire, the combustion rate decreases by 80%, meeting the GB8624-2012 standard, and it can continue to burn for less than 5 seconds under a 1000°C flame.
Extend the lifespan of components
Protect the engine hood hinges, reduce micro-motion wear, and extend the maintenance period from 3 years to 8 years, with a single replacement cost reduced by 400 yuan.
Delay the aging speed of electronic components and plastic parts in the engine compartment.
Material and Structural Characteristics
The typical front compartment insulation layer adopts a polyurethane base material + PVC support layer composite structure. Some high-end products contain:
Aluminum alloy reflective layer (reflects 97% of heat)
Aerogel composite material (thermal conductivity as low as 0.02 W/(m·K))
Self-repair coating or shape memory alloy (active vibration reduction)
Note: In recent years, some vehicle models have had a situation of "downgrading" due to cost control. If the original vehicle does not have an insulation layer, it can be added according to the requirements.
If the underbody insulation layer of the car's front compartment (usually referring to engine compartment insulation foam or insulation board) fails, it may bring safety hazards or affect driving comfort. According to the current (April 2026) publicly available information, the following are key information and response suggestions:
Common Fault Manifestations and Effects
Insulation Layer Aging, Damage： Lead to the engine heat being more easily transferred to the front hood and the driver's cabin， possibly causing：
Excessive heat on the front hood (surface temperature exceeding 80°C)
Increased temperature in the driver's cabin， especially in summer or after long driving
Decreased air conditioning cooling efficiency， increased fuel consumption
Accelerated aging of other components in the engine compartment (such as wiring， plastic parts)
Serious Risk： Fire Hazard
In particular， some Audi A6L models (produced from February 8， 2018 to July 27， 2020) have a risk of fire due to poor sealing of the insulation board， where there is a risk of layer delamination and contact with the exhaust pipe， carbonization under heat， and even fire. This problem has led to a recall of approximately 190，000 vehicles.
If you want to know more, keep reading the other articles on this site!
Please call us if you need such products.
Zhuo Meng Shanghai Auto Co., Ltd. is committed to selling MG&MAXUS auto parts welcome to buy.
