2021 Audi A4 Cooling System Parts

This table covers the engine coolants and antifreeze formulations specified for this cooling system. Typical signs include a rising temperature gauge, rusty or sludged coolant, or a heater that blows cold. Use the chemistry named in the notes. Mixing silicate, OAT and HOAT formulas can gel in the radiator. Read more

17 Coolant / Antifreeze parts are listed for the 2021 Audi A4, from PRESTONE, PEAK, PENTOSIN and 3 other brands. FVP MV5050GAL carries the "Popular" badge.

The Compatible With All Colors section lists 1 option from PRESTONE — grouped under the catalog's "Compatible With All Colors" designation — the notes column spells out what sets them apart. PRESTONE AF3055 is listed in this group.

In the Economy grade, FVP, PRESTONE, VALVOLINE and 1 other brand supply 4 parts: the catalog's value-priced group. A representative part number is FVP MV5050GAL.

The Premium section lists 5 options from PRESTONE and PEAK — a step above OE specification in materials, tolerances or warranty terms. PRESTONE AF2100 is listed in this group.

The Standard Replacement section lists 6 options from PENTOSIN, AISIN, PEAK and 1 other brand — built to original-equipment specification. AISIN ACE010 is listed in this group.

1 ungrouped part is not assigned to a grade, with the same engine-level match.

This table covers the hard pipes and extra hoses in the coolant circuit. Read more

3 Coolant Hose / Pipe parts are listed for the 2021 Audi A4, from REIN and ÜRO PARTS.

Listed part numbers: REIN CHP0663, REIN CHE0958 and ÜRO PARTS 06L121131PRM.

This table covers the seals at the Coolant Hose / Pipe. Typical signs include a wet housing, a drip after sitting, or fluid flung off a rotating shaft. Fix the surface the seal rides on. A new seal on a grooved shaft will leak again. Read more

4 Coolant Hose / Pipe Seal parts for the 2021 Audi A4 come from 3 brands — MAHLE / CLEVITE, AJUSA and FEL-PRO.

Listed part numbers: AJUSA 16098500, FEL-PRO 36130 and MAHLE / CLEVITE C32354, plus the other parts above.

This table covers the Coolant Hose Connector flanges. Read more

One part is listed for the 2021 Audi A4 — VAICO V105890.

This table covers the Coolant Hose Flange plugs. Typical signs include a leak at the drain or glow-plug hole, or a plug that has rounded off. Replace the crush washer and torque to the spec in the notes. Read more

One part is listed for the 2021 Audi A4 — ÜRO PARTS 357121140.

This table covers the Coolant Pipe adapters. Read more

This group shows a single part: ÜRO PARTS 06K121143PRM.

This table covers the overflow / expansion tanks that hold extra coolant. Read more

3 Coolant Reservoir parts for the 2021 Audi A4 come from 3 brands — HELLA, REIN and VAICO.

This group includes HELLA 366365681, REIN EPT0281 and VAICO V105349.

This table covers the intercoolers that cool turbo or supercharger charge air. Read more

5 Intercooler parts are listed for the 2021 Audi A4, from NISSENS, GPD, HELLA and 2 other brands. NISSENS 961466 carries the "Popular" badge.

Listed part numbers: NISSENS 961466, GPD 2711413 and HELLA 366340871, plus the other parts above.

This table covers the radiators that dump engine heat to airflow through the core. Typical signs include overheating in traffic, a wet core, or coolant that disappears with no puddle. Replace the cap if it cannot hold the rated pressure, and bleed the system after the swap. Read more

8 Radiator parts are listed for the 2021 Audi A4, from NISSENS, GPD, VEMO and 4 other brands. TYC 13665 carries the "Popular" badge.

Economy: 2 parts, from GPD and VEMO. A representative part number is GPD 13665.

The Standard Replacement section: 6 options from NISSENS, TYC, UAC and 2 other brands. TYC 13665 is listed in this group.

This group includes TYC 13665 and VEMO V10600108 and the remaining parts above.

This table covers the fan assemblies (and clutches, where listed) that pull air through the radiator. Read more

7 Radiator Fan Assembly parts for the 2021 Audi A4 come from 4 brands — VEMO, TECHPRO, GPD and 1 other brand. The "Popular" part is UAC FA50946C.

The Economy section: 4 options from VEMO and GPD. GPD 2812266 is listed in this group.

Standard Replacement: 1 part, from UAC. A representative part number is UAC FA50946C.

2 further parts sit outside the graded sections, with the same engine-level match.

Listed part numbers: UAC FA50946C, GPD 2812266 and VEMO V15011943, plus the other parts above.

This table covers the shrouds that duct air through the fan and radiator. Read more

One part is listed for the 2021 Audi A4 — SKP SK621318.

This table covers the upper, lower and connecting hoses between radiator, engine and reservoir. Typical signs include swelling, cracks, a soft spot, or a leak at a clamp. Replace adjacent aged hoses while the system is drained — they share the same heat cycle. Read more

This group shows a single part: GATES 52459.

This table covers the Radiator insulators. Read more

2 Radiator Insulator parts for the 2021 Audi A4 come from VNE.

This group includes VNE 41000073 and VNE 41000074.

This table covers the Radiator Insulator sleeves. Read more

This group shows a single part: REIN AVM0730.

This table covers the Radiator mounts. Typical signs include a clunk on takeoff, a vibration at idle, or a separated rubber insert. Support the powertrain before unbolting a mount, and torque the fasteners in the notes. Read more

This group shows a single part: REIN AVM0729.

This table covers the senders that report coolant temperature to the gauge or ECU. Typical signs include a gauge that sits on empty or overheat, or a lamp that does not match what the engine is doing. Rule out the cluster and the wiring before replacing the sender. Read more

10 Temperature Sender / Sensor parts are listed for the 2021 Audi A4, from ULTRA-POWER, VNE, GPD and 5 other brands. ULTRA-POWER 5S1608 carries the "Popular" badge.

Economy: 3 parts, from ULTRA-POWER, GPD and UNITED MOTOR PRODUCTS. A representative part number is ULTRA-POWER 5S1608.

The Standard Replacement section: 6 options from VNE, STANDARD MOTOR PRODUCTS, BECK/ARNLEY and 2 other brands. STANDARD MOTOR PRODUCTS TX275 is listed in this group.

1 ungrouped part is not assigned to a grade, with the same engine-level match.

This table covers the thermostats that open the coolant circuit at the specified temperature. Typical signs include slow warm-up, a gauge that climbs in traffic, or heat that never quite arrives. Replace the housing gasket with the thermostat and bleed the system so a trapped air pocket does not cook the new part. Read more

6 Thermostat parts for the 2021 Audi A4 come from 6 brands — VEMO, BECK/ARNLEY, MOTORAD and 3 other brands. The "Popular" part is BECK/ARNLEY 1430913.

The Economy section: 1 option from VEMO. VEMO V15992133 is listed in this group.

Standard Replacement: 4 parts, from BECK/ARNLEY, MOTORAD, AISIN and 1 other brand. A representative part number is BECK/ARNLEY 1430913.

1 further part sits outside the graded sections, with the same engine-level match.

Listed part numbers: BECK/ARNLEY 1430913, VEMO V15992133 and MOTORAD 838235, plus the other parts above.

This table covers the seals at the thermostat housing and water outlet. Typical signs include a wet housing, a drip after sitting, or fluid flung off a rotating shaft. Fix the surface the seal rides on. A new seal on a grooved shaft will leak again. Read more

3 Thermostat / Thermostat Housing / Water Outlet Seal parts are listed for the 2021 Audi A4, from AJUSA, ELRING and MAHLE / CLEVITE.

Listed part numbers: AJUSA 16502300, ELRING 453710 and MAHLE / CLEVITE C33480.

This table covers the housings and outlets the thermostat sits in. Read more

2 Thermostat Housing / Water Outlet parts for the 2021 Audi A4 come from 2 brands — GATES and MOTORAD.

Part numbers include GATES CO34954 and MOTORAD CH3116.

This table covers the pumps that circulate coolant through the block and radiator. Typical signs include coolant at the weep hole, pulley play, or a growl from the front of the engine. Replace the thermostat and refill with the specified coolant whenever the pump comes off. Read more

16 Water Pump parts for the 2021 Audi A4 come from 10 brands — PIERBURG, BECK/ARNLEY, GATES and 7 other brands. The "Popular" part is US MOTOR WORKS US8124.

The Economy section: 5 options from BECK/ARNLEY, US MOTOR WORKS, FVP and 1 other brand. US MOTOR WORKS US8124 is listed in this group.

Standard Replacement: 11 parts, from PIERBURG, GATES, FOUR SEASONS and 3 other brands. A representative part number is GATES 42209.