Audi Expansion Tank - Meyle 8A0121403A

Product Information

The engine coolant reservoir, also known as an ‘overflow bottle’ is a crucial component of modern vehicle cooling systems. Its job is to capture the increased volume of engine coolant that is created as the coolant is heated and expands. It needs someplace to go, so a coolant line that typically runs from the radiator outlet to the top of the engine coolant reservoir will feed the reservoir, while the reservoir feeds the engine as it needs more coolant to send through the engine and back through the radiator.

Engine coolant reservoirs are typically made of plastic and can be either clear or opaque. Some performance or aftermarket overflow bottles are made of aluminum or other more durable materials.

• Fogging: Over time, due to chemical exposure, age, and heat cycles, the clear plastic used in most engine coolant reservoirs can become foggy and opaque. This can make it difficult to read the coolant level accurately.
• Leaks/ Cracking: The most common area for an engine coolant reservoir to leak is usually at a plastic seam or seal. As the bottle is run through thousands of heat cycles, from ambient temperatures below freezing to 200 degrees Fahrenheit plus, the weakest part of the reservoir, usually a seam or molded junction, can crack and fail.
• Age: Over time, due to age and exposure, the plastic and materials will become brittle and prone to cracking and other age-related failures.
• Coolant leaks: The most common failure of a bad engine coolant reservoir is a coolant leak. This can be slow or minimal, or it can be a total instant failure of the reservoir. If you notice a slow coolant leak and can diagnose it back to the overflow bottle, or coolant reservoir, it is recommended to replace it asap.
• Overheating: A bad engine coolant reservoir can reduce engine cooling system pressure, reducing the effective boiling point of the engine coolant. Depending on temperatures and conditions, this can result in engine overheating.

About Meyle

Meyle Original Parts

The MEYLE ORIGINAL range comprises over 21,000 OE-compliant spare parts for almost all current passenger cars and vans – quality-tested, robust, durable and proven a thousandfold on the roads of the world You can find the parts you need safely and without any mix-ups here and will get them in next to no time thanks to a high level of availability.

The economical alternative to almost all servicing and repairs.

All MEYLE ORIGINAL parts completely comply with the required MEYLE specifications of the vehicle manufacturers and are guaranteed to fit exactly like the original. They score points with their excellent value for money, MEYLE’s high level of quality and tried-and-tested source materials.

First choice for professionals and people with high expectations.

Especially when it comes to the IAM and demanding gearheads, MEYLE ORIGINAL spare parts are an ideal choice to carry out repair and maintenance work professionally, economically and to a high standard! Therefore, MEYLE ORIGINAL spare parts are the first choice when it comes to keeping a vehicle in good working order economically – after all, MEYLE is the ‘driver’s best friend’ and as reliable as a good friend no matter what.