How to replace the coolant reservoir and radiator on Audi A4?

To carry out the task of replacement of the radiator, first raise the front of the vehicle and hold it firmly on jackstands. Take off the bottom splash cover and empty the cooling system. Secondly, remove engine covers and front bumper and in 2.0L models, position radiator support panel in service position. Detach the upper and lower transaxle cooler lines of the automatic and seal them with a cap. Have the upper and bottom radiator hose clips lifted to detach the hose to the radiator and twist them (where needed) to release the O-ring. Take out the ducts by removing the air duct fasteners of either side of the radiator. Unplug the air conditioning pressure switch and ambient temperature sensor on the driver side of radiator and position the harness aside. Disassemble the mounting fasteners of the power steering cooler and drop the cooler without unscrewing the lines where provided. Removal of air conditioning condenser mounting fasteners and rotate the condenser out of and down the radiator, careful not to kink, stretch or bend the air conditioning lines. Unscrew the two radiator mounting pins, push the pins upwards to unscrew then remove the radiator. Installation of new radiator Before fitting the new radiator, replace any damaged hose clips, radiator hoses, and O-rings. Installation is done in the same manner as it is removed. Installation Refill and bleed the system and then start the engine checking all the leaks. In the case of expansion tank, empty the cooling system by draining it until the coolant drier is removed. Removal: Before removing the tank out of the engine compartment, take out the expansion tank mounting screw, lift the tank and disconnect the coolant level sensor connector. The reservoir should be clean and clear, so wash the reservoir with soapy water, and rinse thoroughly, etc. Installation is done in the same manner as it is removed.

Genuine Audi A4 Coolant Reservoir

Coolant Tank Reservoir

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8 Coolant Reservoirs found

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Audi A4 Expansion Tank Part Number: 8K0-121-403-AC
$73.78 MSRP: $103.34
You Save: $29.56 (29%)
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Product Specifications
- Other Name: Tank; Expansion Tank, Reservoir
- Replaces: 8K0-121-403-T, 8K0-121-403-G, 8K0-121-403-H, 8K0-121-403-D, 8K0-121-403-Q
- Warranty: This genuine part is guaranteed by Audi's factory warranty.
Fits the following Vehicles:
- 2009-2016 Audi A4 | Base, Premium, Premium Plus, Prestige | 4 Cyl 2.0 L GAS
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Audi A4 Reservoir Part Number: 8D0-121-403-D
$65.45 MSRP: $91.67
You Save: $26.22 (29%)
Ships in 1-2 Business Days
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Product Specifications
- Other Name: Tank
- Warranty: This genuine part is guaranteed by Audi's factory warranty.
Fits the following Vehicles:
- 1997-2001 Audi A4 | Base | 4 Cyl 1.8 L GAS
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Audi A4 Reservoir Part Number: 8E0-121-403
$76.15 MSRP: $106.65
You Save: $30.50 (29%)
Ships in 1-2 Business Days
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Product Specifications
- Other Name: Tank
- Warranty: This genuine part is guaranteed by Audi's factory warranty.
Fits the following Vehicles:
- 2002-2009 Audi A4 | Base, Cabriolet | 4 Cyl 1.8 L GAS, 4 Cyl 2.0 L GAS, 6 Cyl 3.2 L GAS
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Audi A4 Reservoir Part Number: 8D0-121-403-L
$86.86 MSRP: $121.65
You Save: $34.79 (29%)
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Product Specifications
- Other Name: Tank
- Warranty: This genuine part is guaranteed by Audi's factory warranty.
Fits the following Vehicles:
- 1996-2001 Audi A4 | Avant, Base | 6 Cyl 2.8 L GAS
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Audi A4 Expansion Tank Part Number: 8D0-121-403-M
$106.54 MSRP: $149.21
You Save: $42.67 (29%)
Ships in 1-2 Business Days
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Product Specifications
- Other Name: Tank; Expansion Tank
- Warranty: This genuine part is guaranteed by Audi's factory warranty.
Fits the following Vehicles:
- 2000-2001 Audi A4 | Base | 6 Cyl 2.8 L GAS
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Audi A4 Expansion Tank Part Number: 8W0-121-405-L
$143.99 MSRP: $201.67
You Save: $57.68 (29%)
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Product Specifications
- Other Name: Tank; Expansion Tank, Reservoir
- Replaces: 8W0-121-405-F, 8W0-121-405-G, 8W0-121-405-E
- Warranty: This genuine part is guaranteed by Audi's factory warranty.
Fits the following Vehicles:
- 2017-2020 Audi A4 | Premium, Premium Plus, Prestige, Titanium | 4 Cyl 2.0 L GAS
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Audi A4 Expansion Tank Part Number: 8W0-121-405-K
$55.66 MSRP: $76.67
You Save: $21.01 (28%)
Ships in 1-2 Business Days
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Product Specifications
- Other Name: Tank; Expansion Tank, Reservoir
- Warranty: This genuine part is guaranteed by Audi's factory warranty.
Fits the following Vehicles:
- 2020 Audi A4 | Premium, Premium Plus, Prestige | 4 Cyl 2.0 L GAS
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Audi A4 Reservoir Part Number: 8E0-121-403-A
$59.28 MSRP: $81.65
You Save: $22.37 (28%)
Ships in 1-2 Business Days
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Product Specifications
- Other Name: Tank
- Warranty: This genuine part is guaranteed by Audi's factory warranty.
Fits the following Vehicles:
- 2002-2006 Audi A4 | Base, Cabriolet | 6 Cyl 3.0 L GAS, 6 Cyl 3.2 L GAS

Audi A4 Coolant Reservoir

The Audi A4 Coolant Reservoir ensures that the engine is not exposed to drippage of coolant, which usually drips away; this Coolant Reservoir collects the expanding coolant and releases it back to the engine when the temperature is lower. It sits between the radiator and the hard plastic, which holds the recovery loop together to prevent air flow, prevent rust, and ensure that toxic antifreeze does not touch the floor. Audi A4 has shown two designs, but both manuals bear the Coolant Reservoir name. The non-pressurized overflow type Coolant Reservoir is attached to the radiator with its pressure cap, has a plain plastic lid on the tank, and the hot coolant flows out of the radiator to the tank and back into the radiator under a vacuum as the engine cools. The pressurized expansion design of most Audi products imposes a metal-rated limit on the tank itself, constructs the reservoir of reinforced plastic, and locates it at the high point of the system to allow the interior space to accommodate the expansion of a liquid. The mechanism here is that the pressure accelerates air over the cap and air is pulled back by cooling; this prevents the appearance of bubbles since the tank is raised above the radiator. Level marks are cast on all Coolant Reservoirs to provide drivers with a reference point for topping up when the engine is cold. With or without the version, the Audi A4 Coolant Reservoir has a closed circuit that balances the engine heat and protects the environment. There have been changes in materials and the position of the cap over the years, but all Audi A4s have continued to utilize the same expansion and contraction physics to ensure a smooth drive.

Choose original equipment manufacturer Coolant Reservoir for great performance and strong durability. They use Audi's official craftsmanship and high-grade materials, and meet strict quality standards. Are you looking for quality Coolant Reservoir at a good price? Come to our online store. We carry a wide range of genuine parts for your Audi A4 and the prices are competitive. Each part comes with the manufacturer's warranty. You can install with confidence and get steady results. Over time, you'll save money and avoid hassle. Keep your maintenance simple and protect your vehicle with OEM parts. Get the quality your A4 needs now.

Audi A4 Coolant Reservoir Parts and Q&A

Reservoir
8E0-121-403
Q: How to replace the coolant reservoir and radiator on Audi A4?
A:
To carry out the task of replacement of the radiator, first raise the front of the vehicle and hold it firmly on jackstands. Take off the bottom splash cover and empty the cooling system. Secondly, remove engine covers and front bumper and in 2.0L models, position radiator support panel in service position. Detach the upper and lower transaxle cooler lines of the automatic and seal them with a cap. Have the upper and bottom radiator hose clips lifted to detach the hose to the radiator and twist them (where needed) to release the O-ring. Take out the ducts by removing the air duct fasteners of either side of the radiator. Unplug the air conditioning pressure switch and ambient temperature sensor on the driver side of radiator and position the harness aside. Disassemble the mounting fasteners of the power steering cooler and drop the cooler without unscrewing the lines where provided. Removal of air conditioning condenser mounting fasteners and rotate the condenser out of and down the radiator, careful not to kink, stretch or bend the air conditioning lines. Unscrew the two radiator mounting pins, push the pins upwards to unscrew then remove the radiator. Installation of new radiator Before fitting the new radiator, replace any damaged hose clips, radiator hoses, and O-rings. Installation is done in the same manner as it is removed. Installation Refill and bleed the system and then start the engine checking all the leaks. In the case of expansion tank, empty the cooling system by draining it until the coolant drier is removed. Removal: Before removing the tank out of the engine compartment, take out the expansion tank mounting screw, lift the tank and disconnect the coolant level sensor connector. The reservoir should be clean and clear, so wash the reservoir with soapy water, and rinse thoroughly, etc. Installation is done in the same manner as it is removed.